The Theresa Passive House: A Blueprint for High-Performance Design in Hot-Humid Climates
The Theresa Passive House, nestled in Austin's historic Clarksville neighborhood, stands as a remarkable example of how architectural preservation can harmoniously merge with modern sustainable design. This 2100 square foot residence, completed in 2020, is not merely a renovation and addition to a 1914 Craftsman bungalow; it is a meticulously engineered dwelling that embodies rigorous targets in energy efficiency, indoor air quality (IAQ), thermal comfort, embodied carbon, and responsible materials sourcing.[1] These ambitious goals were established by the Passive House Institute U.S. (Phius), a leading authority in high-performance building standards.
by Positive Energy staff. Photography by Casey Dunn
Redefining Residential Performance
A Historic Blend with Cutting-Edge Sustainability
The Theresa Passive House, nestled in Austin's historic Clarksville neighborhood, stands as a remarkable example of how architectural preservation can harmoniously merge with modern sustainable design. This 2100 square foot residence, completed in 2020, is not merely a renovation and addition to a 1914 Craftsman bungalow; it is a meticulously engineered dwelling that embodies rigorous targets in energy efficiency, indoor air quality (IAQ), thermal comfort, embodied carbon, and responsible materials sourcing.[1] These ambitious goals were established by the Passive House Institute U.S. (Phius), a leading authority in high-performance building standards.
The project achieved full Passive House certification and served as a pilot for the groundbreaking PHIUS 2018+ Source Zero standard.[1] This distinction is particularly significant as it marks the Theresa Passive House as one of the first PHIUS-certified, source-zero projects in a challenging hot and humid climate, specifically ASHRAE Climate Zone 2A.[1] The commitment to these principles has yielded exceptional energy performance, with the home consuming approximately 75% less energy than typical new constructions.[1] This impressive efficiency also earned it the highest rating by Austin Energy Green Building to date.[1] Beyond its reduced energy consumption, the Theresa Passive House functions as its own energy hub, integrating photovoltaic panels and battery backup systems. This provides unparalleled self-sufficiency and resilience, ensuring peace of mind even during extreme weather events and power outages.[1]
Forge Craft, Hugh Jefferson Randolph, and the Pursuit of Passive House Excellence
The creation of the Theresa Passive House was a deeply collaborative endeavor, bringing together the expertise of Forge Craft Architecture + Design (led by Trey Farmer, AIA), Hugh Jefferson Randolph Architects, and Studio Ferme (with Adrienne Farmer contributing to interior design).[1] The homeowners themselves, an architect and a designer, envisioned the house as more than just a personal residence. They conceived it as a "forum for learning" and a tangible "proof point" for the feasibility and benefits of Passive House construction in challenging contexts, such as a modest-sized renovation on a small, urban lot within a hot, humid climate.[1]
This deliberate approach to the project, viewing it as a public demonstration, highlights a critical trend in high-performance building: successful outcomes in challenging climates necessitate a truly integrated design process. Architects, engineers, and specialized consultants must work synergistically from the very inception of a project, rather than operating in isolation. The "proof point" aspect of the Theresa Passive House suggests a broader objective of normalizing Passive House principles in the Southern United States, actively addressing and overcoming perceived barriers like cost and climate suitability through demonstrated success. The design team's commitment to health and sustainability was evident in their financial prioritization; rather than maximizing square footage, they strategically invested in a robust building envelope, a high-performance HVAC system, and on-site solar panels.[2]
Positive Energy's Role as MEP Engineer
Positive Energy, an MEP (Mechanical, Electrical, and Plumbing) engineering firm renowned for its specialization in high-end residential architecture, was a proud partner on this project.[1] Positive Energy's fundamental mission—to transform the way homes are delivered to society by leveraging building science and human-centered design—aligns deeply with core tenets of the Passive House standard.[6] Our expertise is dedicated to engineering spaces that are not only healthy and comfortable but also inherently resilient.
For the Theresa Passive House, Positive Energy's scope of involvement was comprehensive MEP engineering.[1] This deep engagement was instrumental in ensuring the precise integration and optimal performance of the advanced mechanical systems. In a hot and humid climate like Austin, where managing moisture and achieving efficient cooling are paramount, the specialized knowledge and meticulous execution provided by an experienced MEP firm are indispensable for reaching Passive House performance benchmarks. Their involvement from design through construction ensured that the ambitious performance targets were not just theoretical but were realized in the built environment.
Passive House Goes Beyond Energy Savings
The Core Principles of Passive House
Passive House represents a building design standard rooted in extreme energy efficiency and sustainable living, engineered to slash energy consumption by up to 90% compared to conventional structures.[8] It offers a direct pathway to achieving net-zero energy buildings that are also significantly more comfortable, durable, healthy, and predictable in their performance.[10] Originating in Germany in the 1990s, the Passive House concept has undergone substantial evolution, particularly with the Passive House Institute U.S. (Phius) developing climate-specific standards, such as PHIUS+ 2015 and 2018.[3] This adaptation was crucial to make the standard practically feasible across the diverse climates of North America, including the challenging hot and humid regions like Austin.
The PHIUS standard operates on a performance-based framework, underpinned by three primary pillars: stringent limits on annual and peak heating and cooling loads, a cap on overall source energy use, and demanding airtightness requirements.[11] Compliance with these criteria is rigorously verified through energy modeling, ensuring that design intent translates into real-world performance.[12]
Continuous Insulation: Eliminating Thermal Bridges
The principle of continuous insulation dictates that a building must be completely wrapped with insulation to minimize heat flow through its entire envelope.[10] This strategy directly addresses thermal bridging, which occurs where structural elements, such as framing members, possess lower R-values than the surrounding insulation. These interruptions create pathways that allow heat to escape in cold conditions or penetrate in warm conditions, undermining the overall thermal performance of the enclosure. The application of continuous, thick insulation on the exterior of a building is fundamental to maintaining stable indoor temperatures and significantly reducing energy demand.[10]Airtight Construction: The Foundation of Performance
Passive Houses are meticulously designed for extreme airtightness, typically targeting 0.6 air changes per hour at 50 Pascals (ACH@50 Pa) or less.[10] This stringent requirement aims to prevent uncontrolled air leakage, which is a significant vector for both heat and moisture transfer. Air leaks can account for up to 40% of total heat loss even in otherwise well-insulated structures.[15] More critically, in hot-humid climates, warm, moist outdoor air leaking into cooler interior wall cavities can condense, leading to moisture accumulation, potential mold growth, and long-term durability issues within the building fabric itself.[10] Airtightness is empirically verified through a Blower Door Test, a diagnostic tool that measures the rate of air changes per hour under a controlled pressure difference.[14]High-Performance Windows: Balancing Solar Gain and Heat Loss
Windows are inherently complex components of the building envelope, tasked with managing air, water, and heat flow while also providing views and daylight.[10] Passive Houses typically employ triple-glazing and specialized low-emissivity (low-e) coatings to effectively block radiant heat transfer.[10] In a hot climate, the Solar Heat Gain Coefficient (SHGC) of windows is particularly crucial. Windows with a high SHGC are desirable on facades where passive solar heating is beneficial in winter (e.g., east and south orientations), while those with a low SHGC are essential on facades exposed to intense summer sun (e.g., west-facing windows) to prevent unwanted solar heat gain and subsequent overheating.[10]Balanced Ventilation with Heat/Energy Recovery
Given the exceptional airtightness of Passive Houses, controlled mechanical ventilation becomes indispensable to ensure a continuous supply of fresh air and to effectively manage indoor air quality.[10] Energy Recovery Ventilators (ERVs) are commonly employed for this purpose. These systems continuously pull in fresh outdoor air and exhaust stale indoor air, simultaneously transferring heat and moisture between the two airstreams.[10] This process minimizes energy loss while managing latent loads, ensuring a constant flow of fresh, filtered air without compromising the building's thermal comfort or energy efficiency.Dedicated Dehumidification
Relying on the heating/cooling system alone is insufficient to create the necessary drying potential in a building, especially when an air tight envelope and ERV create both interior and exterior latent loads that need to be handled by mechanical means. Dedicated dehumidifiers are critical to decouple the drying function from the heating and cooling systems.Right-Sizing Mechanical Systems for Efficiency
One of the significant advantages of a highly insulated and airtight Passive House envelope is the drastic reduction in heating and cooling loads, which eliminates the need for oversized HVAC systems.[10] This allows for the specification of smaller, less expensive, and inherently more efficient mechanical systems. The upfront investment in a robust building envelope can be partially offset by the savings realized from reduced mechanical equipment costs.[10] The focus shifts to precisely right-sizing and selecting systems that can efficiently handle the minimal and precise loads of the building.
Why Passive House Matters
The benefits of Passive House design extend far beyond mere energy savings, encompassing a holistic improvement in the living environment.
Comfort: Passive Houses are engineered to maintain a remarkably stable indoor temperature, eliminating drafts and cold spots that often plague conventional buildings and ensuring superior thermal comfort for occupants.[2]
Health: The meticulous control over indoor air quality, achieved through continuous mechanical ventilation and advanced filtration, significantly reduces the presence of indoor pollutants and allergens. This proactive management minimizes the risk of respiratory problems and contributes to a healthier living environment.[2]
Durability: The emphasis on high-quality building materials and exacting construction practices, particularly concerning moisture control within the building envelope, contributes to structures that are inherently more durable and capable of withstanding extreme weather conditions over their lifespan.[8]
Resilience: Perhaps one of the most compelling advantages in an era of increasing climate volatility is the inherent resilience of Passive House design. The robust building envelope and energy-efficient systems provide "passive survivability," allowing homes to maintain habitable temperatures for extended periods even during power outages or severe weather events.[1] The Theresa Passive House notably demonstrated this capability during both the extreme cold of Winter Storm Uri and intense summer heat events, as validated by research from the University of Texas.[3]
The evolution of the Passive House standard from its European origins, which primarily focused on heating loads, to the climate-specific PHIUS+ 2015 and 2018 standards for North America, represents a strategic adaptation crucial for broader market penetration. This adaptation acknowledges the unique challenges presented by diverse climates, particularly the significant cooling and dehumidification demands of hot and humid regions like Austin.[3] Without this climate-specific optimization, the standard's applicability in many parts of the United States would be severely limited. The Theresa Passive House's designation as a pilot project for PHIUS 2018+ Source Zero in a hot, humid climate underscores the importance of this ongoing evolution, positioning PHIUS as a leader in making passive building principles effective and accessible across varied environmental contexts.[1]
The relationship among the five Passive House principles is a cornerstone of their effectiveness. For instance, the extreme airtightness achieved in a Passive House fundamentally changes how the building interacts with its environment. This virtual elimination of uncontrolled air infiltration, a major pathway for heat, moisture, and pollutants, then mandates the integration of sophisticated mechanical ventilation systems to introduce fresh air and manage humidity.[10] Conversely, the superior performance of the envelope—through continuous insulation, high-performance windows, and airtight construction—allows for significantly downsized and optimized MEP systems, leading to both cost savings and increased efficiency. This highlights that envelope and mechanical systems are not independent elements but rather an interdependent entity, requiring an integrated design approach for optimal performance.
Key Performance Metrics of Theresa Passive House (vs. Typical Code-Built)
The following table provides a quantitative overview of the Theresa Passive House's performance, contrasting it with typical code-built homes to illustrate the tangible advantages of Passive House design. These metrics demonstrate the practical application of building science principles and the level of performance achievable in real-world projects.
Passive House Principles and Their Practical Application
The following table illustrates how the core principles of Passive House are translated into tangible design and construction elements, using the Theresa Passive House as a concrete example. This breakdown aims to demystify complex concepts by showing their real-world implementation and benefits.
Walls and Roofs in a Hot-Humid Climate
Understanding Wall Assemblies: The Four Control Layers in Practice
Designing a durable and high-performing building enclosure, especially in challenging climates, requires a nuanced understanding of how its various components interact with environmental loads such as rain, temperature, and humidity. Building science principles emphasize the importance of four principal control layers within a wall assembly, each addressing a critical function for long-term durability and performance.[17] These layers, listed in their order of importance for preventing building failure, are:
Water Control Layer: This is the primary defense against liquid water—whether from rain, surface water, or groundwater—from entering the building.[18] Its continuous and robust application is paramount, as a failure in this layer can lead to rapid and catastrophic system failure, including mold, decay, and corrosion.
Air Control Layer: This layer prevents uncontrolled air movement through the building envelope.[22] Air leakage is not merely an energy drain; it carries significant heat and, critically, moisture. In hot-humid climates, warm, humid outdoor air infiltrating cooler interior wall cavities can condense, leading to moisture accumulation, reduced effective R-value of insulation, and potential mold or decay.[10] A continuous, strong, and durable air barrier is essential to mitigate these risks.[18]
Thermal Control Layer: This is the insulation, designed to minimize heat transfer through conduction.[22] While often the most visible component of a high-performance wall, its effectiveness is severely compromised if the air and moisture control layers are not adequately addressed and integrated.[10]
Vapor Control Layer: This layer manages the movement of moisture vapor through building materials via diffusion.[22] Its precise placement and permeability are highly dependent on the specific climate zone and interior conditions. In hot-humid climates, the strategy often involves allowing for "inward drying" or utilizing semi-vapor permeable materials on the exterior to prevent moisture from becoming trapped and accumulating within the assembly.[22]
Theresa Passive House Wall and Roof Design: Strategies for Austin's Climate
Austin, Texas, is classified as ASHRAE Climate Zone 2A – Hot-Humid.[4] This climate presents distinct challenges for building enclosures, primarily characterized by high humidity levels and substantial cooling loads, alongside the potential for inward moisture drive caused by solar heating of exterior surfaces.[10] The Theresa Passive House's envelope design directly addresses these challenges through thoughtful material selection and assembly configuration.
Specific R-Values and Insulation Types: The Theresa Passive House is constructed with a wood frame system.[4] Its walls are designed as framing with continuous insulation, achieving an R-value of 26 and utilizing mineral wool with cavity fill as the insulation material.[4] This approach of combining cavity insulation with continuous exterior insulation is crucial for minimizing thermal bridging and achieving robust thermal performance. The roof is an unvented assembly with an R-value of 33.[4] Unvented roofs are frequently favored in hot-humid climates because they offer superior control over interior moisture and effectively prevent solar-driven moisture from entering the roof deck.[24] The floor sits above a crawlspace and is insulated to an R-value of 14.[4] For fenestration, Marvin windows were selected, featuring a Whole Window U-Value of 0.17 and a Solar Heat Gain Coefficient (SHGC) of 0.26.[4] This low SHGC is particularly vital for mitigating unwanted solar heat gain in a climate dominated by cooling needs.[10]
The Blower Door Test and Its Significance
A hallmark of the Theresa Passive House's performance is its extraordinary airtightness, measured at 0.036 ACH@50 Pa.[4] This figure is remarkably lower, indicating a far more airtight enclosure, than the PHIUS certification requirement of 0.6 ACH@50 Pa.[12] The Blower Door Test, a crucial diagnostic tool, quantifies the airflow between the interior and exterior of a structure, pinpointing areas of air leakage.[15] The test creates a controlled pressure difference, typically 50 Pascals, to simulate wind conditions, and then measures the resulting air changes per hour.[15] This extreme level of airtightness is a fundamental cornerstone of Passive House design, as it prevents significant energy loss and uncontrolled moisture movement. However, it simultaneously necessitates the integration of controlled mechanical ventilation to ensure a continuous supply of fresh air.[10] The extremely low ACH@50 achieved by the Theresa Passive House powerfully demonstrates that airtightness is not merely an energy-saving measure but a foundational prerequisite for creating a truly controlled indoor environment. For architects, this means recognizing that embracing airtightness as a design priority shifts the responsibility for air exchange from random leaks to precisely engineered mechanical systems, enabling superior indoor air quality and humidity control.Moisture Management in Unvented Roofs with Asphalt Shingles
In hot-humid climates, unvented roof assemblies, particularly those utilizing asphalt shingles, demand a specific and critical moisture management strategy: the installation of a vapor barrier between the asphalt shingles and the roof deck.[24] This is due to the nature of asphalt shingles, which, similar to traditional wood shingles, can act as a reservoir for water from dew and rain.[24] When these shingles are heated by solar radiation, the stored moisture can be driven inward through permeable roofing felts into the underlying roof deck (typically plywood or OSB), potentially leading to moisture accumulation and material degradation such as buckling.[24] The solution involves using an impermeable roofing underlayment, which functions as a vapor barrier. This layer effectively prevents this inward moisture drive, thereby controlling moisture transmission through the roof assembly and eliminating shingle buckling and moisture issues within the roof deck.[24] This detail is paramount for ensuring the long-term durability of the roof in hot, humid environments and maintaining the integrity of the roof deck.[25]
Practical Takeaways for Durable Wall Assemblies
For architects, a deep understanding of the climate-specific behavior of wall assemblies is paramount. In hot-humid climates, the primary focus shifts from preventing outward moisture drive (as is common in cold climates) to meticulously managing inward moisture drive and preventing condensation within the assembly, which occurs when humid outdoor air encounters cooler interior surfaces.[10] The Theresa Passive House serves as a compelling demonstration that robust thermal control, exemplified by its R-26 walls and R-33 roof [4], combined with exceptional air control (0.036 ACH@50 Pa [4]) and precise vapor control (such as the specific vapor barrier in its unvented roof [24]), is not only achievable but essential for ensuring both durability and high performance in such challenging climates.
The selection of materials like mineral wool for the walls and the specific unvented roof assembly reflects a sophisticated understanding of hygrothermal performance in Austin's climate. The design prioritizes assemblies that can effectively "dry" in the appropriate direction, preventing moisture accumulation within the building fabric.[4] This approach aligns with the "perfect wall" concept, which, in hot-humid climates, often implies placing the primary thermal and vapor control layers on the exterior side of the structure. This strategy helps keep the sheathing warm and minimizes the risk of condensation, or it effectively manages inward vapor drive. This illustrates that achieving high performance while maintaining durability in a challenging climate requires that "more insulation" be accompanied by "smarter assembly design."
Theresa Passive House Envelope Specifications
The following table provides a detailed overview of the Theresa Passive House's key envelope specifications, offering concrete examples of the components and performance metrics that contribute to its high-performance status in a hot-humid climate.
Positive Energy's MEP Solutions
The Imperative of Indoor Air Quality in Airtight Homes
In highly airtight Passive Houses, the focus on indoor air quality (IAQ) becomes paramount. Because natural infiltration, or uncontrolled air leakage, is virtually eliminated, pollutants can accumulate within the living space if not properly managed through mechanical means.[21]
Common indoor pollutants and their sources are diverse and pervasive in residential settings. These include combustion products from unvented stoves, furnaces, or tobacco; off-gassing from building materials like insulation, wet carpet, or pressed wood products; chemicals from furnishings and household cleaning products; and emissions from human activities such as cooking and cleaning.[21] These sources can introduce a range of contaminants, including carbon dioxide (CO2), Volatile Organic Compounds (VOCs), and fine particulate matter (PM2.5).[21]
To define and ensure "acceptable indoor air quality," the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) developed Standard 62.2, "Ventilation and Acceptable Indoor Air Quality in Residential Buildings".[27] This standard serves as the recognized benchmark for residential ventilation design, specifying minimum ventilation rates and other measures to minimize adverse health effects for occupants.27 ASHRAE 62.2 defines "Whole Building" Mechanical Ventilation using the formula: Q fan = 0.03A floor + 7.5 (BR + 1).[26] In this equation, A floor represents the conditioned floor area, serving as a proxy for material sources that might off-gas pollutants, while BR (Bedrooms) acts as a surrogate for the number of occupants and their activities. The standard also provides "Source Control" Exhaust Ventilation requirements for specific areas. For instance, kitchens require 100 cfm (cubic feet per minute) of on-demand ventilation or 5 ACH (air changes per hour) continuously, while full bathrooms require 50 cfm on-demand or 20 cfm continuously.[26] The development of ASHRAE 62.2 was instrumental in overcoming initial builder resistance to constructing airtight homes by providing a clear and accepted method for ensuring proper IAQ.[27]
Theresa Passive House's Integrated MEP System
Positive Energy's MEP engineering for the Theresa Passive House exemplifies a highly sophisticated and integrated approach to environmental control. This level of integration is particularly critical for a building that is not only located in a hot and humid climate but also boasts an exceptionally airtight envelope.[1] The comprehensive system is aptly described as the "workhorse" that enables much of the Theresa Passive House's performance.3
Variable Refrigerant Flow (VRF) Heat Pump AC: Efficient Heating and Cooling
The Theresa Passive House employs a Mitsubishi Variable Refrigerant Flow (VRF) heat pump AC unit for its primary heating and cooling needs.[3] VRF systems are highly advantageous in high-performance homes because their variable capacity allows them to precisely match the significantly reduced heating and cooling loads. Unlike oversized conventional units that cycle frequently and inefficiently, VRF systems can operate for longer durations at lower capacities, which is crucial for effective latent heat (moisture) removal.[19] This precise control enhances both energy efficiency and occupant comfort.Energy Recovery Ventilation (ERV): Delivering Fresh Air and Managing Latent Loads
A Panasonic Intellibalance 1000 ERV system is integral to delivering continuous fresh air throughout the Theresa Passive House.[3] The fundamental function of an ERV is to exchange both sensible heat and latent heat (moisture) between the incoming fresh outdoor air and the outgoing stale indoor air.[10] In a hot, humid climate, this is particularly vital: the ERV transfers moisture from the wetter incoming outdoor air to the drier exhaust air, thereby significantly reducing the latent load that the cooling system would otherwise have to handle.[19] This mechanism is crucial for maintaining excellent indoor air quality in an airtight home by continuously flushing out pollutants while simultaneously minimizing the energy penalty associated with conditioning untreated outdoor air.[10]Dedicated Dehumidification: The Key to Comfort in Humidity
Complementing the VRF and ERV systems, the Theresa Passive House incorporates a dedicated dehumidifier.[3] Even with an efficient VRF system and an ERV managing the latent load from ventilation air, a dedicated dehumidifier is often indispensable in hot, humid climates like Austin. This component allows for precise control of indoor humidity levels without the need to overcool the space to achieve dehumidification.[19] While ERVs are effective at reducing the moisture burden from incoming ventilation air, they do not fully dehumidify the entire indoor air volume.[19] The dedicated dehumidifier ensures optimal thermal comfort by maintaining desired humidity levels (typically 50-55% Relative Humidity), which is critical for occupant well-being and preventing potential mold growth within the building.[20] This focus on latent load management is a critical consideration in hot-humid climates, as a standard AC system alone is often insufficient for optimal comfort and durability in a high-performance, airtight home. A dedicated strategy for latent load management, typically involving an ERV for ventilation air and a separate dehumidifier for internal moisture, is not merely a luxury but a fundamental requirement for preventing mold, ensuring comfort, and protecting the building fabric.Hospital-Grade Air Filtration: Ensuring Clean Air (MERV Ratings Explained)
The Theresa Passive House integrates a MERV16 filtration system [3], a commitment to indoor air quality beyond typical residential standards. Air filter effectiveness is quantified by its MERV (Minimum Efficiency Reporting Value) rating, which measures a filter's ability to trap particles ranging from 0.3 to 10 microns in size.32 Higher MERV ratings indicate superior filtration capabilities.[32]
MERV 1-4: Offer minimal filtration, capturing larger particles like dust and pollen.[32]
MERV 5-8: Common in residential and commercial settings, capable of capturing mold spores, dust mites, and household lint.[32]
MERV 9-12: Provide improved IAQ, trapping finer dust, pet dander, some bacteria, and mold spores. Filters in this range are often used in hospitals, although not in surgical settings.[32]
MERV 13-16: Recommended for environments demanding high air quality, capable of capturing particles as small as 0.3 microns, including bacteria, viruses, smoke, and smog. These are frequently used in commercial buildings, hospitals, and clean rooms.[32]
MERV 17-20 (HEPA): Represent the highest level of filtration, typically used in specialized settings like surgical rooms and cleanrooms, capable of removing 99.97% of 0.3-micron particles, including viruses and combustion smoke. These are generally not suitable for standard residential HVAC systems due to significant airflow restriction, [32] but do provide superior protection against a wide spectrum of airborne contaminants, including allergens, pollutants, and even some viruses and bacteria.[32] This level of filtration offers substantial benefits, particularly in regions with high allergen counts or during public health concerns.[3] This commitment to high-level filtration signifies a growing trend where high-performance homes are not merely about energy efficiency but also about creating inherently healthier indoor environments. In airtight homes, filtration becomes the primary defense mechanism against both outdoor and indoor airborne contaminants.
Heat Pump Hot Water Heater: Energy-Efficient Domestic Hot Water
The MEP system further includes a heat pump hot water heater.[3] Heat pump water heaters are considerably more energy-efficient than traditional electric resistance models, contributing significantly to the overall low energy consumption profile of the Passive House.[14]
How Positive Energy Ensures Optimal Performance
Positive Energy's approach to the Theresa Passive House demonstrates how individual MEP components are meticulously integrated to function as a cohesive, high-performing system. The extreme airtightness of the Passive House envelope, measured at an impressive 0.036 ACH@50 Pa [4], allows the mechanical systems to operate with unparalleled precision, as uncontrolled air leakage, which would otherwise introduce unpredictable loads, is virtually eliminated.[10]
The combination of a VRF system, an ERV, and a dedicated dehumidifier represents a highly targeted strategy for hot-humid climates. This trifecta effectively addresses both sensible (temperature) and latent (humidity) loads.[19] The ERV efficiently handles the latent load introduced by incoming fresh air, while the dedicated dehumidifier precisely manages internal latent loads, preventing the AC system from overcooling the space in an attempt to remove excess moisture.[19]
A critical aspect of Positive Energy's involvement was collaboration with the means/methods team during construction to ensure design intent was met.[3] This process is essential to verify that all complex systems are installed correctly, calibrated precisely, and operate as designed to achieve the rigorous Passive House performance targets.[21] Construction phase collaboration ensures that the theoretical design performance translates into real-world operational excellence, maximizing the comfort, health, and efficiency benefits for the occupants.
Indoor Air Quality Parameters and ASHRAE 62.2 Requirements
For architects seeking to understand the intricacies of indoor air quality, the following table outlines key parameters, their significance, health implications, and how ASHRAE 62.2 provides a framework for achieving acceptable indoor air quality.
Theresa Passive House MEP System Components and Functions
This table details the specific MEP system components engineered by Positive Energy for the Theresa Passive House, highlighting their functions and benefits within the context of a high-performance home in a hot-humid climate.
Lessons from the Theresa Passive House
Passive Survivability: Performance During Extreme Weather Events
The Theresa Passive House stands as a powerful demonstration of climate resilience, a core benefit of Passive House design that extends beyond daily energy savings.[1] Its performance during extreme weather events provides compelling evidence of its robust design.
During the unprecedented Winter Storm Uri, which brought single-digit temperatures to Austin and caused widespread power outages and burst pipes in many conventional homes, the Theresa Passive House maintained an indoor temperature of approximately 47 degrees Fahrenheit after three days without power.[3] This remarkable passive survivability demonstrates a significant "cushion of time" for occupants, ensuring safety and comfort even when the grid fails.[3]
Similarly, researchers at the University of Texas (UT Austin) conducted studies on the home's ability to tolerate extreme heat, comparing its performance to a code-built house. After 12 hours on a sweltering summer day, the code-built house reached a stifling 98 degrees Fahrenheit, while the Passive House registered a much more comfortable 83 degrees.[1] This highlights the effectiveness of its robust envelope and design strategies in mitigating heat gain, even without active cooling. This performance during both extreme cold and heat showcases that high-performance homes are not just energy-efficient but also robust climate adaptation tools, shifting the value proposition from purely operational cost savings to essential safety and quality of life benefits in an era of increasing climate volatility. Further enhancing its resilience, the home operates as its own energy hub, generating electricity through photovoltaic panels and utilizing battery backup to provide full backup power and self-sufficiency during grid outages.[1]
Source Zero Certification: Producing More Energy Than Consumed
A crowning achievement for the Theresa Passive House is its PHIUS 2018+ Source Zero certification.[1] This designation signifies that the building produces more energy than it consumes on an annual basis, specifically accounting for "source energy".[1] Source energy is a more comprehensive metric than site energy, as it includes all energy consumed from generation at the power plant through transmission and delivery to the building, providing a more accurate measure of environmental impact.[11]
As the only PHIUS-certified, source-zero project in the Southern United States, the Theresa Passive House sets a new benchmark for energy efficiency and serves as a pioneering model for climate action in residential construction.[1] This achievement underscores that true sustainability in building extends beyond merely reducing energy consumption. It involves actively contributing to the energy grid's decarbonization by producing clean, renewable energy. For architects, aiming for Source Zero means integrating on-site renewables, such as photovoltaic panels and battery storage, as an intrinsic part of the design, working in tandem with the super-efficient envelope and MEP systems. This elevates the goal from simply "doing less harm" to "actively doing good" for the environment and the grid, establishing a higher standard for future projects.
The Theresa Passive House as a Case Study for Future Builds and Community Education
The homeowners of the Theresa Passive House actively embraced its role as a "proof point" and a learning opportunity. They engaged extensively with the community, hosting events for product companies and welcoming students from the University of Texas at Austin to visit, openly sharing data and designs as a living case study.[1] This commitment to knowledge dissemination has been instrumental in demystifying Passive House principles and showcasing their practical application.
The impact extends beyond this single project. Trey Farmer of Forge Craft is actively applying Passive House principles to affordable multifamily housing projects, demonstrating the scalability and broader applicability of these crucial benefits to a wider range of communities.[3] The project's excellence and influence have been widely recognized, garnering numerous accolades, including the prestigious 2024 AIA Housing Award, PHIUS' Passive Project of the Year – Retrofit, and Austin Green Awards.[1] These awards underscore its significant impact and recognition within the architectural and building science industries, further cementing its status as an inspiring blueprint for future high-performance construction.
Empowering Architects for High-Performance Futures
The Theresa Passive House stands as a compelling testament to the transformative potential of high-performance building design, particularly in challenging hot and humid climates. Its success demonstrates that achieving superior energy efficiency, indoor air quality, thermal comfort, and resilience is not merely a collection of disparate technologies but an integrated science.
For architects seeking to design durable, healthy, and efficient homes, several key principles emerge from this project:
Prioritize the Building Envelope: A robust, continuous, and airtight building envelope—encompassing walls, roofs, and high-performance windows—is the fundamental prerequisite for energy efficiency, effective moisture control, and consistent thermal comfort. This demands a meticulous understanding and implementation of all four control layers: water, air, vapor, and thermal, with careful consideration of their climate-specific interactions.
Embrace Controlled Mechanical Ventilation: In highly airtight structures like Passive Houses, mechanical ventilation with energy recovery (ERV) is not optional; it is essential for maintaining superior indoor air quality and effectively managing latent loads. This controlled approach ensures a continuous supply of fresh, filtered air while preserving energy efficiency.
Right-Size and Integrate MEP Systems: The inherent efficiency of the high-performance envelope allows for significantly smaller, more efficient mechanical systems, such as Variable Refrigerant Flow (VRF) heat pumps. Furthermore, in hot and humid climates, dedicated dehumidification is crucial for achieving optimal comfort and preventing moisture-related durability issues, as it addresses latent loads precisely without overcooling.
Invest in Advanced Air Filtration: Implementing high-MERV filtration is vital for ensuring a healthy indoor environment. This protects occupants from a wide range of airborne pollutants, allergens, and even some pathogens, a benefit that has gained increasing importance in public health considerations.
Design for Resilience: Beyond the immediate benefits of energy savings, architects must consider passive survivability and active energy independence (through integrated photovoltaics and battery storage). These features are critical for ensuring occupant safety and comfort during increasingly frequent extreme weather events and power outages, making homes truly future-proof.
The profound success of the Theresa Passive House is a powerful endorsement of the value of an integrated design process. This project clearly illustrates that when architects, building science consultants, and MEP engineers collaborate from the earliest stages of conception, the full potential of high-performance design can be unlocked. Positive Energy's pivotal role as MEP Engineer and Commissioning Agent was indispensable in translating the ambitious performance targets into a functional, resilient, and healthy home. Their specialized expertise in climate-specific MEP solutions, particularly tailored for hot and humid environments, underscores the critical contribution of specialized engineering in achieving Passive House certification and pushing beyond it to Source Zero. For architects, partnering with experienced MEP engineers and building science consultants is not just about achieving compliance; it is about empowering the creation of homes that are healthier, more comfortable, more durable, and genuinely climate-resilient for their occupants, setting an inspiring blueprint for the future of residential architecture.
Works cited
Theresa Passive - Forge Craft Architecture, accessed May 28, 2025, https://forgexcraft.com/portfolio/theresa-passive/
Theresa Passive House by Forge Craft Architecture + Design ..., accessed May 28, 2025, https://architizer.com/projects/theresa-passive/
There Will Come Soft Rains - Texas Architect Magazine, accessed May 28, 2025, https://magazine.texasarchitects.org/2022/11/07/there-will-come-soft-rains/
Theresa Passive House | Phius, accessed May 28, 2025, https://www.phius.org/certified-project-database/theresa-passive-house
Theresa Passive House | The American Institute of Architects, accessed May 28, 2025, https://www.aia.org/design-excellence/award-winners/theresa-passive-house
Passive House — Positive Energy, accessed May 28, 2025, https://positiveenergy.pro/passive-house
Positive Energy | Building Science Focused MEP Engineering, accessed May 28, 2025, https://positiveenergy.pro/
MEP Design for Passive Houses: Tips and Considerations - Innodez, accessed May 28, 2025, https://innodez.com/mep-design-for-passive-houses-tips-and-considerations/
Phius Market Penetration in the US: A Comparative Analysis with Typical Code-Built Houses, accessed May 28, 2025, https://positiveenergy.pro/building-science-blog/2025/5/26/phius-market-penetration-in-the-us-a-comparative-analysis-with-typical-code-built-houses
Passive Building Design Guide - Phius, accessed May 28, 2025, https://www.phius.org/sites/default/files/2022-04/phius-commercial-construction-design-guide.pdf
Passive Building on the Rise - ASHRAE, accessed May 28, 2025, https://www.ashrae.org/technical-resources/high-performing-buildings/passive-building-on-the-rise
www.phius.org, accessed May 28, 2025, https://www.phius.org/sites/default/files/2022-04/Phius%202021%20Standard%20Setting%20Documentation%20v1.1.pdf
www.ashrae.org, accessed May 28, 2025, https://www.ashrae.org/technical-resources/high-performing-buildings/passive-building-on-the-rise#:~:text=These%20form%20the%20main%20passive,recovery%20ventilation%20(Figure%201).
BSD-025: The Passive House (Passivhaus) Standard—A comparison to other cold climate low-energy houses | buildingscience.com, accessed May 28, 2025, https://buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard
Passive House and Blower Door Test - Rothoblaas, accessed May 28, 2025, https://www.rothoblaas.com/blog/passive-house-e-blower-door-test
All About Blower Door Test Equiment and Results - Prosoco, accessed May 28, 2025, https://prosoco.com/blower-door-tests-learn-the-basics-now/
PASSIVE HOUSE WALL ASSEMBLY PERFORMANCE – A CASE STUDY - RDH Building Science, accessed May 28, 2025, https://www.rdh.com/wp-content/uploads/2017/11/CCBST-2017-Passive-House-Wall-Assembly-Performance.pdf
Moisture-Related Durability of In-Service High-R Wall Assemblies in Pacific Northwest Climates - RDH Building Science, accessed May 28, 2025, https://www.rdh.com/wp-content/uploads/2017/10/Smegal-Durability-High-R-Walls-Pacific-NW-1.pdf
HVAC, ERV, and Dehumidifier in new coastal home : r/buildingscience - Reddit, accessed May 28, 2025, https://www.reddit.com/r/buildingscience/comments/1b4r6yx/hvac_erv_and_dehumidifier_in_new_coastal_home/
Expanding Passive House ERV & HVAC Options - EkoBuilt, accessed May 28, 2025, https://ekobuilt.com/blog/expanding-passive-house-erv-hvac-options/
Indoor Air Quality in Passivhaus Dwellings: A Literature Review - PMC, accessed May 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7369996/
BSI-120: Understanding Walls\* | buildingscience.com, accessed May 28, 2025, https://buildingscience.com/documents/building-science-insights-newsletters/bsi-120-understanding-walls
Moisture Control For Buildings, accessed May 28, 2025, https://buildingscience.com/sites/default/files/migrate/pdf/PA_Moisture_Control_ASHRAE_Lstiburek.pdf
buildingscience.com, accessed May 28, 2025, https://buildingscience.com/sites/default/files/document/rr-0306_unvented_roof_hh_shingle_rev.pdf
buildingscience.com, accessed May 28, 2025, https://buildingscience.com/sites/default/files/migrate/pdf/RR-0108_Unvented_Roof_Systems.pdf
The Inside Story: A Guide to Indoor Air Quality | CPSC.gov, accessed May 28, 2025, https://www.cpsc.gov/Safety-Education/Safety-Guides/Home/The-Inside-Story-A-Guide-to-Indoor-Air-Quality
www.energy.gov, accessed May 28, 2025, https://www.energy.gov/sites/prod/files/2014/12/f19/ba_innovations_2014_ASHRAE%2062_2.pdf
Standards 62.1 & 62.2 - ASHRAE, accessed May 28, 2025, https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2
Read-Only Versions of ASHRAE Standards, accessed May 28, 2025, https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards
ASHRAE 62.2 - Air King Indoor Air Quality Standards, accessed May 28, 2025, https://www.airkinglimited.com/ashrae-62-2/
Ventilating dehumidifier vs ERV + dehumidifier for hot humid climate - GreenBuildingAdvisor, accessed May 28, 2025, https://www.greenbuildingadvisor.com/question/ventilating-dehumidifier-vs-erv-dehumidifier-for-hot-humid-climate
A Quick Guide to MERV Ratings for Better Indoor Air Quality - RectorSeal, accessed May 28, 2025, https://rectorseal.com/blog/merv-ratings-dust-free
What MERV Rating Do I Need For My Home HVAC System? - Filti, accessed May 28, 2025, https://filti.com/what-merv-rating-do-i-need/
What is a MERV rating? | US EPA, accessed May 28, 2025, https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating
Choose the Air Filter That's Right for Your San Antonio Home | Aramendia Service Experts, accessed May 28, 2025, https://www.aramendia.com/blog/which-air-filter-is-right-for-you-2/
Phius Market Penetration in the US: A Comparative Analysis with Typical Code-Built Houses
The adoption of Phius passive building standards in the United States, while demonstrating a robust upward trend, currently constitutes a small fraction of the overall construction market, which is predominantly characterized by buildings constructed to meet minimum code requirements. Phius certified buildings offer substantial advantages over typical code-built houses, most notably in their superior energy efficiency, which translates to significant reductions in operational energy consumption and associated costs. Furthermore, these high-performance buildings provide enhanced indoor air quality, increased durability, and a greater level of resilience against extreme weather events and power outages. The number of Phius certified projects and the total square footage of these projects have been steadily increasing across the US, reflecting a growing interest in and adoption of these advanced building principles. Moreover, the integration of Phius standards into the energy codes of several states and municipalities indicates a growing recognition of their value in achieving ambitious energy efficiency and sustainability goals. This report aims to provide a comprehensive, data-driven analysis of the current market penetration of Phius standards within the US construction sector, offering a comparative perspective against conventional code-compliant building practices and assessing the implications for the future of sustainable building in the nation.
By Positive Energy staff
The adoption of Phius passive building standards in the United States, while demonstrating a robust upward trend, currently constitutes a small fraction of the overall construction market, which is predominantly characterized by buildings constructed to meet minimum code requirements. Phius certified buildings offer substantial advantages over typical code-built houses, most notably in their superior energy efficiency, which translates to significant reductions in operational energy consumption and associated costs. Furthermore, these high-performance buildings provide enhanced indoor air quality, increased durability, and a greater level of resilience against extreme weather events and power outages. The number of Phius certified projects and the total square footage of these projects have been steadily increasing across the US, reflecting a growing interest in and adoption of these advanced building principles. Moreover, the integration of Phius standards into the energy codes of several states and municipalities indicates a growing recognition of their value in achieving ambitious energy efficiency and sustainability goals. This report aims to provide a comprehensive, data-driven analysis of the current market penetration of Phius standards within the US construction sector, offering a comparative perspective against conventional code-compliant building practices and assessing the implications for the future of sustainable building in the nation.
Introduction to Phius Passive Building Standards
Phius, or Passive House Institute US, stands as the leading certification program for passive building design and construction in North America 1. Its primary mission is to drive the adoption of passive and net-zero energy buildings into the mainstream of the construction industry 4. Phius achieves this by offering rigorous certification programs for building projects, for products and components used in these buildings, and for the professionals who design and deliver them 4. The core concept of passive building, as championed by Phius, revolves around five fundamental principles that work synergistically to create highly energy-efficient, comfortable, and healthy structures 5. These principles include the use of continuous insulation throughout the entire building envelope to minimize thermal bridging, the creation of an extremely airtight building envelope to prevent uncontrolled air leakage, the employment of high-performance windows and doors that effectively manage solar heat gain, the implementation of balanced heat- and moisture-recovery ventilation to ensure excellent indoor air quality, and the resulting ability to utilize a minimal space conditioning system due to the significantly reduced heating and cooling demands 5.
Phius offers several distinct certification programs tailored to different needs and project goals. Phius CORE represents the organization's legacy certification, focusing on optimizing the balance between passive and active conservation strategies to achieve superior energy performance and high-quality construction 8. This program provides flexibility through both a performance-based compliance path suitable for all building types and a limited-scope prescriptive path designed for single-family homes and townhouses 8. Building upon the foundation of Phius CORE, Phius ZERO sets its sights on achieving net-zero source energy consumption on an annual basis 8. This ambitious standard mandates the use of renewable energy sources, either on-site or off-site, to offset the building's energy needs and explicitly prohibits the use of fossil fuels for combustion within the building 8. Recognizing the critical need to address the existing building stock, Phius REVIVE 2024 offers a pioneering framework for deep energy retrofits 8. This standard prioritizes not only significant decarbonization but also the enhancement of resilience in existing buildings, ensuring they can better withstand the impacts of climate change 8. A key differentiator of the Phius approach is its commitment to climate-specific standards 1. Phius recognizes that optimal energy efficiency and cost-effectiveness require design strategies that are carefully tailored to the unique climate conditions of different regions across North America 1. By taking into account factors such as local temperature extremes, humidity levels, solar radiation, and energy costs, Phius standards guide builders toward solutions that are both high-performing and economically sound 1.
The Landscape of US Residential and Commercial Building Codes
The regulatory framework governing building construction in the United States is characterized by a decentralized system where the primary authority for adopting and enforcing building codes rests with state and local jurisdictions 11. Unlike some other nations, the US does not have a single, comprehensive national building code that applies uniformly across all regions, with the notable exception of manufactured housing, which is subject to federal standards 11. Instead, most states and municipalities choose to adopt and adapt model building codes developed and maintained by organizations such as the International Code Council (ICC) and the National Fire Protection Association (NFPA) 11. These model codes provide a set of minimum standards for various aspects of building design, construction, alteration, materials, maintenance, and performance, with the overarching goal of protecting public health, safety, and general welfare 11.
In recent decades, energy efficiency has become an increasingly important consideration in building codes. Many jurisdictions have incorporated energy efficiency requirements into their local codes, often based on model energy codes such as the International Energy Conservation Code (IECC) 14. The IECC sets minimum standards for the energy-efficient design of buildings, addressing aspects like insulation, building envelope tightness, heating and cooling system efficiency, and lighting 15. The typical energy performance of houses built to meet these minimum code requirements can be assessed using the Home Energy Rating System (HERS) Index 16. On this index, a "Reference Home," representing a standard house built to the specifications of a model energy code, receives a score of 100 16. Lower HERS scores indicate better energy performance, with very efficient homes often achieving scores of 60 or below 16. For comparison, homes that earn the ENERGY STAR certification, a widely recognized standard for energy efficiency, are required to be at least 15 percent more energy-efficient than homes built to the current code, and they typically achieve efficiencies that are 20 to 30 percent better than standard new homes 14. Some jurisdictions have adopted more stringent energy codes or offer incentives for building beyond the minimum requirements, leading to homes that can be up to 44 percent more energy-efficient than those built to older code versions 17.
The construction characteristics of houses built to code are defined by the minimum standards outlined in these regulations 12. Codes specify minimum levels of insulation for walls, roofs, and foundations, as well as requirements for window performance and ventilation 12. While some level of airtightness is often mandated, the requirements are typically less stringent than those of passive building standards like Phius 19. It is important to recognize that the primary focus of building codes is to ensure the fundamental safety, health, and structural durability of buildings 12. Energy efficiency is an important but often secondary consideration, aiming to set a baseline level of performance rather than pushing for ultra-low energy consumption 12. Consequently, a building that is described as being "up to code" meets the minimum legal standards for construction but may not necessarily represent a high-performance building in terms of energy efficiency or overall sustainability 18.
Quantifying Phius Market Penetration in the US
Assessing the current market penetration of Phius passive building standards in the US requires an examination of the available data on certified projects and a comparison with the overall construction activity in the country. While the precise figures may vary across different sources and reporting periods, the general trend indicates a growing, albeit still relatively small, presence of Phius certified buildings in the US construction landscape. As of various reporting dates, Phius has certified over 640 projects across the United States, encompassing more than 7.4 million square feet of building area 20. More recent data suggests that the total certified square footage has surpassed 11.2 million 3, with 416 projects certified in total as of 2023 21. The rate of certification has also been increasing, with 58 projects earning Phius certification in 2023 alone, compared to 39 in the previous year 22
Breaking down these figures further reveals the distribution across different building types. In the residential sector, Phius has certified over 3,300 individual housing units, with more than 7,000 units having achieved either full certification or pre-certification status 1. While one report from September 2023 indicated that only 224 single-family homes had been certified with Phius 26, other data suggests that single-family homes constitute a larger proportion of the overall Phius project portfolio, potentially around 60.8% 20. This discrepancy may be due to differences in reporting periods or the inclusion of pre-certified projects. The multifamily sector has also seen significant growth in Phius adoption, with over 175 multifamily projects certified as of 2023 27. In the commercial building sector, as of July 2024, there were 454 certified PHIUS buildings 28. It is important to note that the relationship between the total number of certified "projects" and "buildings" may vary depending on the source and the way data is categorized.
Phius certified projects can be found in 42 states and provinces across North America, demonstrating a broad geographical reach 1. Notably, several states and municipalities have formally recognized the value of Phius standards by incorporating them into their energy codes. These include Massachusetts, New York, Illinois, and Washington at the state level, as well as Boulder, Denver, and Chicago at the municipal level 20. This regulatory inclusion is a significant driver for increased adoption in these regions. The growth trend in Phius certifications has been substantial in recent years 1. In 2023, there was a remarkable 49% increase in the number of projects achieving final certification, and the total square footage of certified projects grew by over 52% compared to the previous year 21.
To understand the market penetration of Phius relative to typical construction, it is crucial to compare the number of certified projects with the overall volume of building permits issued in the US. In January 2025, the total number of building permits authorized for privately-owned housing units in the US was at a seasonally adjusted annual rate of approximately 1.473 million to 1.483 million 33. This figure includes around 993,000 to 996,000 single-family permits and approximately 355,000 to 427,000 permits for units in buildings with five or more units 34. While comprehensive national data on total commercial building permits for 2024 is less readily available in the provided snippets, localized data and the number of certified PHIUS commercial buildings (454 as of July 2024) suggest significant activity in this sector as well 28.
The sheer scale of overall building permit numbers in the millions annually, when compared to the hundreds of Phius certified projects, clearly indicates that Phius currently represents a very small fraction of the total US construction market. However, the consistent and substantial year-over-year growth in Phius certifications signifies an increasing interest and adoption of these high-performance building standards.
Table 1: Phius Certified Projects in the US: Key Statistics and Growth Trends Note: Data represents various reporting periods as specified by noted sources.
Phius Certified Buildings vs. Code-Built Houses: A Detailed Comparison
Phius certified buildings offer a compelling alternative to typical code-built houses across several critical performance metrics, most notably in energy efficiency. Studies and real-world data consistently demonstrate that Phius buildings consume significantly less energy for heating and cooling. Savings in the range of 40-60% are commonly reported 5, with some sources indicating even more substantial reductions, up to 75-95% compared to standard homes built to energy codes 42. The PHIUS+ 2015 standard, specifically designed for North American climates, claims an impressive 86% less energy for heating and 46% less for cooling when compared to a building compliant with the 2009 International Energy Conservation Code (IECC) 43. Overall, Phius certified buildings are reported to perform up to 85% better than conventional buildings in terms of energy consumption 6. While specific HERS Index scores for Phius projects aren't consistently provided in the snippets, the magnitude of these energy savings strongly suggests that Phius buildings would achieve significantly lower scores than a code-built reference home (HERS 100) and likely fall well into the range considered very energy efficient (HERS below 60) 16.
The perception of higher upfront construction costs often associated with passive house construction is being increasingly challenged by data from Phius certified projects. Many reports indicate that Phius projects can be built with minimal to no additional upfront costs compared to code-compliant buildings 5. While some estimates do suggest a cost premium, such as 3-5% for single-family homes and 0-3% for multifamily projects over an ENERGY STAR baseline 6, or even a higher range of 7-15% in some cases 44, these figures can vary depending on factors like project size, location, design complexity, and the experience of the construction team. Notably, larger multifamily and commercial projects often benefit from economies of scale, which can effectively reduce or eliminate any initial cost difference 6.
Indoor environmental quality is a paramount concern in Phius certified buildings. Achieving certification requires superb indoor air quality, which is ensured through a combination of an extremely airtight building envelope and a balanced heat- and moisture-recovery ventilation system 5. This system continuously supplies fresh, filtered air while expelling stale air and recovering energy, leading to a comfortable and healthy indoor environment free from drafts and with very stable temperatures 6. The airtightness of Phius buildings also plays a crucial role in preventing moisture problems like condensation and mold growth, further contributing to improved indoor air quality 6. Moreover, Phius certification incorporates the U.S. EPA Indoor airPLUS protocol, adding an extra layer of assurance for comprehensive indoor air quality protection 1.
Durability and resilience are also key advantages of Phius certified buildings. The holistic design approach and the meticulous attention to detail in the construction of the building enclosure ensure long-term durability 1. The robust and highly insulated building envelope makes Phius buildings significantly more resilient in the face of natural disasters and extreme weather events, including wildfires and extreme heat or cold 5. Their ability to maintain comfortable and safe indoor temperatures for extended periods during power outages is a particularly valuable aspect of their resilience 5. Furthermore, the rigorous quality control processes inherent in the Phius certification process ensure a high level of safety and performance for both the building and its occupants 5.
Table 2: Comparison of Phius Certified Buildings and Typical Code-Built Houses
Factors Influencing Phius Market Adoption
The adoption of Phius passive building standards in the US is influenced by a variety of factors, both driving its growth and presenting potential barriers to wider market penetration. Several key drivers are contributing to the increasing interest in and implementation of Phius standards. The growing inclusion of Phius standards within state and local energy codes and their recognition as an alternative compliance pathway in regions like Massachusetts, New York, Washington, Denver, Boulder, and Chicago is a significant catalyst 20. This regulatory endorsement not only legitimizes passive building practices but also creates a more favorable environment for their adoption. There is an increasing awareness among building owners, occupants, and industry professionals regarding the importance of energy efficiency, thermal comfort, and healthy indoor environments 23. Phius certified buildings directly address these concerns by delivering superior performance in these areas. The escalating focus on decarbonization and the urgent need for climate-resilient buildings are also driving the adoption of high-performance standards like Phius, which offers a proven pathway to significant reductions in operational carbon emissions and enhanced resilience against extreme weather events 3.
The availability of comprehensive training and professional certification programs offered by Phius plays a crucial role in expanding the pool of qualified professionals who can design, build, and verify passive buildings 3. This growing expertise within the industry is essential for meeting the increasing demand for Phius certified projects. The potential for substantial long-term cost savings due to the significantly reduced energy consumption of Phius buildings is another compelling driver for their adoption, making them an increasingly attractive investment for building owners who prioritize lifecycle costs 5. The alignment of Phius certification with other recognized green building standards, such as DOE Zero Energy Ready Home, EPA Indoor airPLUS, and ENERGY STAR, can streamline the certification process and enhance the market appeal of Phius projects 1. Finally, the availability of financial incentives and the inclusion of Phius standards in Qualified Allocation Plans in some states can help to offset any perceived initial cost premiums and further encourage developers to pursue passive building 23.
Despite these positive drivers, several potential barriers may hinder the widespread adoption of Phius standards. One persistent challenge is the perception among some developers and builders that passive house construction entails significantly higher upfront costs 46. While data suggests that this is not always the case, this perception can create resistance. Overcoming this barrier requires clear communication and wider dissemination of accurate cost data from successful Phius projects. Another hurdle is the lack of familiarity with passive building principles and the specific requirements of Phius certification within the broader construction industry 19. Increased education and outreach efforts are needed to raise awareness and build capacity within the industry. In some regions of the US, the availability and cost of specialized materials and components required for passive house construction may also pose a challenge 46. Furthermore, the deeply ingrained building codes and traditional construction practices in the US can sometimes create inertia and slow the adoption of more advanced standards 55. Finally, the successful implementation of passive building techniques often requires adjustments to traditional construction workflows and may necessitate investment in training the existing workforce 56.
The increasing integration of Phius standards into building codes and incentive programs provides a powerful mechanism for driving market adoption. By formally recognizing and supporting passive building practices through regulatory frameworks, jurisdictions are signaling their commitment to high-performance construction and creating a more level playing field for developers and builders who choose to pursue these standards. This top-down approach can effectively overcome some of the initial resistance associated with unfamiliarity or perceived cost risks, leading to a more significant impact on the overall market penetration of Phius.
Conversely, the persistent perception of higher upfront costs, even when not consistently supported by data, remains a significant obstacle to wider adoption. Economic considerations are paramount in the construction industry, and if developers and builders are not convinced of the financial viability of Phius construction, they may be hesitant to embrace it. Addressing this barrier requires a concerted effort to provide clear, transparent, and compelling data that demonstrates the economic advantages of Phius, including reduced energy bills, lower maintenance costs, and potentially higher property values, thereby making it a more attractive and ultimately more popular choice.
Future Outlook
In conclusion, the market penetration of Phius passive building standards in the United States, while still representing a small segment of the overall construction market, is marked by significant and accelerating growth. This upward trend underscores the increasing recognition of the substantial benefits offered by Phius certified buildings, particularly in terms of energy efficiency, indoor air quality, durability, and resilience. As energy efficiency mandates become more stringent, concerns about climate change intensify, and the demand for healthier and more resilient buildings continues to rise, the importance of Phius standards will likely grow. The future potential for wider adoption is considerable, fueled by the increasing integration of Phius into building codes and incentive programs, the growing awareness among industry professionals and the public, and the compelling evidence of long-term cost savings and enhanced building performance. Phius is increasingly positioned as a key solution for achieving a zero-carbon built environment in the United States and has the potential to transition from a niche market to a more mainstream construction standard as its advantages become more widely understood and the remaining barriers to adoption are effectively addressed. The growing network of Phius certified professionals across the US is a critical factor in this positive outlook, providing the necessary expertise and capacity to support the continued expansion of passive building practices in the years to come.
Works Cited
1. Project Certification Overview - Phius, accessed March 13, 2025, https://www.phius.org/certifications/projects/project-certification-overview
2. PHIUS+ Certification Takes You One Step Closer Toward NGBS Green, accessed March 13, 2025, https://www.ngbs.com/documents/18-passive-house-certification-takes-you-one-step-closer-towards-ngbs-green.pdf
3. Phius | Phius Zero is the goal. Phius is the means., accessed March 13, 2025, https://www.phius.org/
4. Phius Certifications, accessed March 13, 2025, https://www.phius.org/certifications
5. What is Passive Building - Phius, accessed March 13, 2025, https://www.phius.org/passive-building/what-passive-building
6. Passive Building FAQs | Phius Passive House FAQs, accessed March 13, 2025, https://www.phius.org/passive-building/what-passive-building/passive-building-faqs
7. Phius CORE Standard Specifications, accessed March 13, 2025, https://www.phius.org/phius-core-standard-specifications
8. Phius Standards, accessed March 13, 2025, https://www.phius.org/standards
9. Decarbonization & Resilience: New Phius Retrofit Standard Open for Public Comment, accessed March 13, 2025, https://www.phius.org/decarbonization-resilience-new-phius-retrofit-standard-open-public-comment
10. The Phius Difference, accessed March 13, 2025, https://www.phius.org/phius-difference
11. Building Codes, Standards, and Regulations: Frequently Asked Questions | Congress.gov, accessed March 13, 2025, https://crsreports.congress.gov/product/pdf/R/R47665
12. Home Construction: What House Codes Are and Why They Matter - AEI Inspections, accessed March 13, 2025, https://aeiinspections.com/home-construction-house-codes-why-matter/
13. Housing and building codes - Local Housing Solutions, accessed March 13, 2025, https://localhousingsolutions.org/housing-policy-library/housing-and-building-codes/
14. Local Residential Energy Efficiency | US EPA, accessed March 13, 2025, https://www.epa.gov/statelocalenergy/local-residential-energy-efficiency
15. Residential Buildings Factsheet - Center for Sustainable Systems - University of Michigan, accessed March 13, 2025, https://css.umich.edu/publications/factsheets/built-environment/residential-buildings-factsheet
16. A Look at the Most Common Home Energy Rating Systems - Rise, accessed March 13, 2025, https://www.buildwithrise.com/stories/a-look-at-the-most-common-home-energy-rating-systems
17. How Energy Codes Make Homes More Efficient - IMT - Institute for Market Transformation, accessed March 13, 2025, https://imt.org/resources/how-energy-codes-make-homes-more-efficient/
18. What does building “to code” really mean? - Charlotte - Cluck Design, accessed March 13, 2025, https://www.cluckdesign.com/cluck_news/what-does-building-to-code-really-mean/
19. What is a Passive House? | TBDA - Tom-Bassett-Dilley Architects, accessed March 13, 2025, https://tbdarchitects.com/what-is-passive-house/
20. Building the Case for Passive House Standards - Multi-Housing News, accessed March 13, 2025, https://www.multihousingnews.com/making-the-case-for-passive-house-standards/
21. Phius 2023 Annual Report, accessed March 13, 2025, https://www.phius.org/sites/default/files/2024-08/Phius%202023%20Annual%20Report.pdf
22. Taking Stock of 2023, Looking Ahead to 2024 - Phius, accessed March 13, 2025, https://www.phius.org/taking-stock-2023-looking-ahead-2024
23. Passive House Adoption & Codification a Growing Building Trend in 2024 - PRWeb, accessed March 13, 2025, https://www.prweb.com/releases/passive-house-adoption--codification-a-growing-building-trend-in-2024-302046431.html
24. Phius Project Certification, accessed March 13, 2025, https://www.phius.org/certifications/projects
25. North Carolina Housing Finance Agency Attn: Tara Hall 3508 Bush St Raleigh, North Carolina 27609 August 15, 2024 RE: 2025 North, accessed March 13, 2025, https://www.nchfa.com/sites/default/files/2024-09/PhiusAllianceNorthCarolina8.15.24.pdf
26. Project One - Cross Construction, accessed March 13, 2025, https://www.buildwithcross.com/project-one
27. Methodology & Modeling Parameters - The Passive House Network, accessed March 13, 2025, https://passivehousenetwork.org/wp-content/uploads/2023/10/PHN-RDH-Comparison-Study-Methodology-Report.pdf
28. Commercial Buildings Factsheet - Center for Sustainable Systems - University of Michigan, accessed March 13, 2025, https://css.umich.edu/publications/factsheets/built-environment/commercial-buildings-factsheet
29. Certified Project Database | Phius, accessed March 13, 2025, https://www.phius.org/certified-project-database
30. Energy Codes - Phius, accessed March 13, 2025, https://www.phius.org/resources/policy-work/energy-codes
31. Measuring Passive House Energy Performance - GreenBuildingAdvisor, accessed March 13, 2025, https://www.greenbuildingadvisor.com/article/measuring-passive-house-energy-performance
32. Refocusing the Mission, Revamped Website, and Retrofits: Phius 2022 Year in Review, accessed March 13, 2025, https://www.phius.org/refocusing-mission-revamped-website-and-retrofits-phius-2022-year-review
33. US Building Permits Monthly Trends: New Residential Construction - YCharts, accessed March 13, 2025, https://ycharts.com/indicators/us_building_permits
34. United States Building Permits - Trading Economics, accessed March 13, 2025, https://tradingeconomics.com/united-states/building-permits
35. United States Residential Building Permits | Moody's Analytics, accessed March 13, 2025, https://www.economy.com/united-states/residential-building-permits
36. New Residential Construction Press Release - U.S. Census Bureau, accessed March 13, 2025, https://www.census.gov/construction/nrc/current/index.html
37. Building Permits Inch Up 0.1% in January - dshort - Advisor Perspectives, accessed March 13, 2025, https://www.advisorperspectives.com/dshort/updates/2025/02/19/building-permits-inch-up-january-2025
38. U.S. Construction Industry Data [Updated March 2025 ], accessed March 13, 2025, https://constructioncoverage.com/data/us-construction-spending
39. New Privately-Owned Housing Units Authorized in Permit-Issuing Places: Total Units (PERMIT) | FRED, accessed March 13, 2025, https://fred.stlouisfed.org/series/PERMIT
40. Cleveland, Ohio Sees Record $3.11 Billion in Commercial Construction Permits in 2024, accessed March 13, 2025, https://www.constructconnect.com/construction-economic-news/cleveland-ohio-sees-record-3.11-billion-in-commercial-construction-permits-in-2024
41. UPDATED: 2024 commercial building permit interactive map - Business Record, accessed March 13, 2025, https://www.businessrecord.com/2024-commercial-building-permit-interactive-map/
42. Achieving Net-Zero Living: Passive House Standards That Are On The Rise - Oknoplast USA, accessed March 13, 2025, https://oknoplast.us/achieving-net-zero-living-passive-house-standards-that-are-on-the-rise/
43. Passive House Institute US (PHIUS) - BetterBuiltNW, accessed March 13, 2025, https://betterbuiltnw.com/bpa-multi-family/passive-house-institute-us
44. 6 Estimates of Passive House Cost | Rob Freeman, accessed March 13, 2025, https://robfreeman.com/6-estimates-passive-house-cost/
45. Cost Data - Phius, accessed March 13, 2025, https://www.phius.org/resources/policy-work/cost-data
46. No longer a niche, Passive House standards becoming a solution for highly efficient affordable housing - Canary Media, accessed March 13, 2025, https://www.canarymedia.com/articles/enn/no-longer-a-niche-passive-house-standards-becoming-a-solution-for-highly-efficient-affordable-housing
47. Deep Dive on Phius (for Professionals) - Michigan Net Zero Homes, accessed March 13, 2025, https://minetzero.com/deep-dive-on-phius-for-professionals/
48. Passive house design builds climate resilience, manages costs, accessed March 13, 2025, https://www.poah.org/news/passive-house-design-builds-climate-resilience-manages-costs
49. Achieve Phius CORE REVIVE 2021, accessed March 13, 2025, https://www.phius.org/achieve-phius-core-revive-2021
50. Building a Passive House vs Conventional Home | Energy Efficient Homes - Carmel Building & Design, accessed March 13, 2025, https://www.carmelbuilding.com/2023/08/14/building-a-passive-house-vs-conventional-home-energy-efficient-homes/
51. Passive House Murder Mystery Part IV: Phius Goes Mainstream, accessed March 13, 2025, https://www.phius.org/passive-house-murder-mystery-part-iv-phius-goes-mainstream
52. Guide to Passive House | Northeast Energy Efficiency Partnerships, accessed March 13, 2025, https://neep.org/guide-passive-house
53. Understanding passive house standards: A guide for American Homeowners, accessed March 13, 2025, https://oknoplast.us/understanding-passive-house-standards-a-guide-for-american-homeowners/
54. Zooming In on Phius, an Increasingly Popular Passive Building Certification, accessed March 13, 2025, https://www.multihousingnews.com/zooming-in-on-phius-an-increasingly-popular-passive-building-certification/
55. Passive Homes: What Are They and Why Is the U.S. Behind in Building Them? - Azure Road, accessed March 13, 2025, https://www.azureroad.io/passive-homes-what-are-they-and-why-is-the-u-s-behind-in-building-them/
56. 018115-passive house requirements-PHIUS 2021 - Kalin Associates, accessed March 13, 2025, https://kalinassociates.com/wp-content/uploads/2022/01/018115-passive-house-requirements-PHIUS-2021.docx
The Fine Homebuilding Interview: Kristof Irwin
By Aaron Fagan, Kristof Irwin, originally published in The Fine Homebuilding Magazine, Issue 300 - July 2021
By Aaron Fagan, Kristof Irwin, originally published in The Fine Homebuilding Magazine, Issue 300 - July 2021
A professional engineer offers a consilient view of building science that prioritizes human thriving.
Synopsis: In the fourth installment of the Fine Homebuilding interview series, Aaron Fagan interviews Kristof Irwin, an engineer who wants us all to rethink what it means to live indoors. By focusing on human thriving, Irwin says, and viewing our indoor environment as greatly involving human health, we can cultivate a new relationship with our homes and all that they embody.
A principal of Positive Energy in Austin, Texas, professional engineer Kristof Irwin has an expanded view of building science. He asserts that any definition of the discipline is incomplete without accounting not only for the house as a system, but also for the fact that a home operates as a node in a larger societal and planetary system.
“The paradigm needs to change,” Irwin said during our interview. “Fundamentally, homes should be about human thriving.” And he believes this is an attainable goal—one that isn’t reliant on unrealized technologies of the future. The building industry needs to undergo a cultural shift, he says, and all of us need to cultivate a new relationship to our homes and all that they embody.
According to Irwin, we have the tools we need already to create long-lasting, healthy homes. He asks us to consider this question: Is it time to stop focusing on doing things better and start focusing on doing better things?
AF: How would you describe the focus of your building-science practice and work as an engineer from a cultural point of view?
KI: I really want people to rethink what it means to live indoors. We view an indoor environment as though it’s merely visual, spatial, and economic. When I say we, I mean those within the architecture, engineering, and construction professions. As a result, homeowners and developers are complicit in that view. However, from a very pragmatic standpoint, when we talk about actually being in your home, what we really mean is you are in the air contained by your home, and that means being in a highly immersive tactile situation where visual, spatial, and economic concerns must be secondary to human health.
For example, phthalates are a class of chemical plasticizers used in myriad building products. Even if you put indoor breathing aside, we can still get a substantial transdermal uptake of these chemicals, which are now being linked to a wide variety of health concerns.
That is one of many facts we are going to have to confront in the building industry regarding the health of our built environments. The paradigm needs to change. Fundamentally, homes should be about human thriving. We cannot put the very systems upon which we provide energy and resources for our homes, which are in natural ecosystems, out of that view. In thermodynamics, for example, you define a boundary, and what we tend to do is define the boundary around the home or the lot. That myopia is inappropriate and damaging.
I’ve been rethinking what it means to practice building science, which has been conventionally described as systems theory applied to buildings based on the physical sciences. That last piece is very important; typically, it’s the classic sciences like thermodynamics, hygrothermal dynamics, or, more broadly, physics, chemistry, biology, geology, and engineering disciplines. However, what’s critical to systems thinking is accurate, timely feedback. That principle is huge for the role Fine Homebuilding plays in the culture of home building. One of the most crucial developments for the steam engine was the centrifugal governor. It provided accurate timely feedback of the pressure buildup, which turned it from a grenade to an engine. Culture change is complicated because the very systems we rely on for accurate timely feedback to our society are working through implicit biases.
Where building science is concerned, the elephant in the room, the “emperor has no clothes” reality, is that there are essentially no compelling constraints to keep us from making fantastic buildings. And I mean multiple simultaneous dimensions of quality. These buildings could last 500 years, they could provide flawless air quality, and they could help improve sleep, life expectancy, cognition, and emotional regulation. We know how to design environments to promote human thriving, but we don’t do it.
AF: Why don’t we do it?
KI: Well, it’s not because we are waiting for some invention of appropriate materials. or technologies. It’s because society is not asking us for those outcomes. Society is stuck in outmoded visual, spatial, and economic ideas. Something is wrong with the system when builders and developers see the houses they build as an economic asset for themselves.
So, my point of view is that systems thinking is important, but that it’s incomplete without social science. It needs to include behavioral psychology. We are offering food for thought here.
Fine Homebuilding offers nutrients to this ecosystem, but the ecosystem needs to recognize these as nutrients and consume them. The field of building science has been offering food and society is saying, “I’m not hungry.” I think building science should be using architecture, engineering, and systems thinking to design and build beautiful buildings that achieve practical outcomes. And when I say systems thinking, I mean an expanded view.
AF: There is no sense in talking about window flashing and vapor control if we don’t know why we are doing what we are doing.
KI: Exactly. If someone says “vapor permeance” to me one more time, I think I’ll explode. It’s as if we have a group of architects and builders at a job site and there is a huge pile of dirt we need to load into a truck, and we are lost in conversation about the shovels on the ground. Does it have a long or short handle? Is it flat or pointed? Hickory or ash? What we need to do is pick up the shovel closest to us and get to work. People need to recognize that the dominant pollutant-source exposure in our society is the air breathed in the home. We breathe 30 lb. of air per day, and that’s if we’re not exercising. Where does it go? It goes into our blood. It quickly crosses from outside of me into something I call me. Those pollutant particles go from the air around us into our blood and they have myriad health effects. Covid-19 has gone a long way toward making the invisible substantive. We are really at a point in our societal evolution where homes can be an essential part of the solution to the challenges we face. The climate solution in particular. But we need to prioritize human thriving in the homes we build.
AF: Health risks appear inextricably linked to other risks.
KI: One of the most hopeful things I’ve learned recently is that firms like BlackRock—with nearly $9 trillion in assets under management—are recognizing the enormity of these environmental issues. Larry Fink, BlackRock’s CEO,wrote in his January 2020 annual letter that “climate risk is investment risk.” So, what we have is an extremely powerful system of systems—I’m talking about the financial and banking sector—and they are urgently calling for transparency regarding climate risk. Banks are cleansing their balance sheets of investments that they view as exposed to climate risk, because if they don’t know where the risks are, how can they make decisions for their investors? This has already happened in Europe. It’s happening in Asia. The financial and banking sector says it’s urgent for companies to disclose these risks. Now apply that to the building industry.
AF: That’s the paradigm shift. That will have cascading implications.
KI: That’s exactly right. Think about the way we generate and deliver electricity to our homes. Utility companies are still using outdated science from the ’80s and ’90s. That’s a major source of distortion. A report with detailed modeling was released last December by a group called Vibrant Clean Energy in Boulder, Colo. It will require a major investment to bring it to scale, but if we invest in clean-energy renewables and distributed storage, this model shows that we can save close to half a trillion dollars in the next 30 years. But we need to think differently and go away from traditional practices.
However, the inertia of traditional practices is significant. We have generations of mostly men in the construction industry who would have to face a lot of pain. It means developing a huge amount of humility in order to really get new momentum behind this transition. They need to say to themselves, “My actions and decisions over the course of my life and my career—including the ones I’m making today—are actually part of the problem.” I say this to myself, and it’s hard. It’s not easy, but I know it’s the truth.
I can face that truth, and it’s not comfortable. One of the most important changes the building industry needs to make is that its systems exploit the environment, exploit labor, and promote a host of other unjust practices. We can’t shy away from the negative emotions that conjures. That’s feedback. As we stated before, systems require accurate timely feedback.
I think there is no other reality than the fact that the climate is weirding. Humans need to radically—and I mean unrealistically fast—change their behavior. That’s really hard, and it’s going to be challenging. But what’s happening right now is that we’re not even admitting that we need to do that wholeheartedly and with unified voice. That last piece, “with unified voice,” means there is no way around the fact that—grudgingly, over time—every-one will have to stop the party, go through the hangover, face reality, hit bottom, and say, “Yes, this is real. It’s happening, and we need to deal with it.”
There is a subtle form of optimism in there in the sense that there is no other forward. There’s no other future than gradually people will come to face this reality and accept it. When that happens, powerful change can happen rapidly.
AF: How would you reframe our definition of building science?
KI: I really see that building science needs to expand its purview and its understanding of systems. And I see it in three main areas: planetary systems, human systems, and digital systems. We’ve talked a lot about planetary systems. The good news there is that climate risk is investment risk. Planetary systems are about how we avail ourselves, our families, and our entire society and economy of energy and resources harvested from the planet.
An example of a human system would be that I am an engineer, and I work with architects, builders, contractors, consultants, code officials, inspectors, appraisers,underwriters, bankers, insurers, legislators,commissioners, lobbyists, industry associations, and media outlets including magazines, podcasters, bloggers, and influencers. Every human interaction has an impact.
What my local HVAC distributor chooses to carry, for example, impacts my ability to design, which impacts my installing contractor’s ability to move into the future. What I’m driving at is this expanded building-science systems perspective, and it really includes each individual as a node in a giant mind. And when it comes to human systems, how do we avail ourselves of adjacent expertise.
Medical science, social psychology, behavioral science, behavioral economics, and even marketing and consumer behavior are subjects of expertise. So, there’s all these adjacent expertise sets, and here we are in 2021—it’s not OK with me that they’re siloed next to me. I really feel that for me to do my job, I need to understand that I don’t understand. I have a small purview; I need to ask questions. I need to be able to face the fear and doubt that recognizes that what I’ve done in the course of my career, while traditional, was unskillful. That’s a tough thing to ask for.
We have to ask ourselves what’s on our dashboard when we move through the world, because those instruments shape what we see. You can put profits and consumer preferences on there, but I want to add health and wellness, thermal comfort, operational and embodied energy, and community and environmental health. So, we’ve had the wrong dashboard. Can you blame people for not charting a skillful course? Is it any wonder when we look at what has been prioritized? No.
And then the last one is digital systems. The psychologists who work for big tech fuel the attention economy, and that has bred an age of distraction with huge side effects. This goes back to the beginning of our conversation: If you want to understand something, think about the intent.
Big tech, along with advertisers, are getting the outcomes they were after.
AF: There’s a lot of stored power and intention in tradition.
KI: We shouldn’t bemoan the fact that traditional practices are powerful. That is deeply built into our mammalian selves. Tradition is like guardrails. But, we’re supposed to be thinking beings, not just traditional beings. Traditionally speaking, th e practice has been to create buildings out of basically cheap interchangeable parts so that we can apply low-skilled, exploitable labor, and get a very low dollar-per-square-foot building that looks like a nice home but isn’t. It has interior finishes and gadgets, but don’t peel back the walls! We didn’t optimize it to be a nice home, we only optimized it to look like a nice home delivered at a low first cost. And given that that has been our intent, we’re doing a good job.
I talk about the important difference between doing things better and doing better things. We are engaged right now in the building world with a constant search for doing things better—better wall flashings, better insulations, etc. I think it’s a really timely opportunity to break from that tradition and start thinking about doing better things. Are we prioritizing embodied carbon? Are we prioritizing health? Doing things better has an implicit basis in traditional behavior. Doing better things means thinking, what aren’t we thinking about?
One of the things I think drives our deep fear and concern in the United States building industry—and has us resisting acknowledging it—is the fact that traditional practices are failing us. We don’t want to admit that. Why? That issue makes us bristle so much because in our heart of hearts we don’t trust ourselves to take care of it. We’re not sure that we’re up to the task.
Our behavior communicates that we’re not sure human nature is basically good, creative, intelligent, and caring enough to deal with this problem we’ve created. I will for the rest of my life stand firmly on the idea that we can do this. We can do better things. We can make this happen, but I can also feel the doubt. I think that doubt in humanity’s ability to fix this issue is a source of a lot of resistance to the willingness to change. We need a lot of people producing better things instead of just doing things better.
I can nerd out about European versus U.S. filtration standards, but what really enlivens me and what I really feel connected to right now at this point in my career is this question: How do we get society to admit that it’s due to do things differently? It’s fascinating. As an engineer who wants society to thrive, I am starting to recognize that it’s not by doing engineering, it’s by getting society to ask me to do better and better things. It’s a weird kind of place to be as a quantitative, technical person. It’s very clear to me that the problem is not quantitative or technical; the problem is deeply emotional. We need cultural things that help galvanize societal will.
How do we get there? How do we get past seeing a home as a visual, spatial, economic situation and see it more fully as a deeply tactile situation that influences our very cognition and emotional state? It’s so much more interesting, but we don’t want to go there. Fear is always a story in the mind about what happens next. There are different types of dopamine receptors in the brain, and one of them is associated with the anticipation of the cessation of suffering. It sounds kind of Buddhist. That dopamine trigger is like finding the solution to a problem, and thinking therefore that the problematic situation is nearly gone. That’s not the reality. We don’t think of the fact that we are going to put a mammal into this box we built, and our felt sense of an indoor environment is vastly dominated by unconscious inputs we can no longer ignore.