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Posts tagged indoor air quality
Positive Energy's Education and Advocacy Efforts

Our comprehensive approach to MEP engineering and building science consulting is deeply rooted in a strategic vision that extends far beyond individual project delivery. Our commitment to the idea of "Healthy people, healthy planet” is unwavering. It is not just a statement, but a guiding principle that permeates our extensive education and advocacy efforts. Through the firm’s Building Science Blog and The Building Science Podcast, we aim to actively cultivate knowledge everywhere we can, demystifying complex technical concepts like indoor air quality and intricate wall assembly dynamics for architects and the broader industry. This accessible knowledge transfer empowers architects to confidently integrate advanced building science into their designs, mitigating risks and ensuring the long-term performance and durability of their projects.

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Architectural Design, Building Science, Code, Electrification, Embodied Carbon, Healthy Home, High Performance Homes, Passive House, Phius, Natural Building Material, Mechanical Design, MEP2040, Indoor Air Quality, HVAC, Heat PumpsPositive EnergyPositive Energy, MEP engineering, building science, high-end residential architecture, healthy spaces, comfortable spaces, resilient spaces, human-centered design, MEP design/engineering, custom home market, mission, conditioned space, employee well-being, project partner relationships, "Healthy people, healthy planet" vision, collaboration, architects, contractors, owner representatives, lived experience of architecture, indoor space upgrade, mission-focused engineering, healthier indoor environments, electrification, fossil fuel solutions, education, advocacy, market development, high-performance buildings, AEC industry, building science blog, Building Science Podcast, technical information, continual learning, educational content, blog posts, building resilience, energy systems, building enclosures, indoor air quality, moisture dynamics, wall assemblies, ventilation strategies, sealed attics, dehumidification, roof assemblies, "ping pong water, " indoor air pollution, IAQ code, fossil gas appliance emissions, electrification of domestic hot water, hydronic systems, natural building materials, biophilic design, net-zero energy, carbon footprints, risk mitigation, podcast, Kristof Irwin, M. Walker, philosophical aspects of building science, ethics, aesthetics, systemic aspects of building science, high-energy physics, custom builder, AIA BEC, AIA COTE, human factors, integrating ethics and aesthetics, risk management in AEC, bioclimatic design, system thinking, industry transformation, technical solutions, IAQ and materials, material supply chains, philosophical society, critical thinking, speaking engagements, Architectural Paradigms and Adaptation, Building Science 2.0, Facades+, PhiusCon, Passive House, BS + Beer, battery capacity sizing, ASHRAE, AIA Austin Design Excellence Conference, Science and Storytelling, Code Change, ATX Building Performance Conference, True Sustainability and Regeneration, Healthy Buildings, Earthen Construction, Gulf Coast Green, International Builder Show, Testing Protocols, University Guest Lectures, Earthen Architecture, Systems-Thinking Lens, Cooling, Passive House in Emerging Markets, Climate Change, Building Envelope, Refrigeration Cycle, Mechanical Systems, Air as Material, Psychrometrics, Ventilation, Organization & Committee Memberships, ASHRAE TC-2.1, ASHRAE SSPC-55, ASHRAE SSPC-62.2, MEP2040, RESNET, AIA Austin's Building Enclosure Council, AIA Austin's Committee On The Environment, Phius Alliance Austin, Humid Climate Conference, Phius Alliance, BS + Beer Northwest Arkansas, Habitat for Humanity, Industry Publications, Fine Homebuilding Magazine, Journal of Light Construction, Radiant Cooling.
Marfa Ranch

The Marfa Ranch is a distinguished residential project by Lake Flato Architects, is thoughtfully situated on a low rise within the expansive, pristine desert grasslands of Marfa, Texas. This unique location, nestled between the Chihuahuan Desert and the majestic Davis Mountains, presents a challenging yet profoundly beautiful environment. The architectural design of the ranch consciously adopts a low profile, comprising eight distinct structures meticulously organized around a central courtyard. This layout, shaded by native mesquite trees, serves as a cool respite from the sun-drenched desert beyond its walls, drawing inspiration from the area's earliest regional architectural traditions. Architect Bob Harris of Lake Flato articulated that the design embodies a "deliberate quality of spareness that matches the qualities of the land," emphasizing the importance of the house maintaining a low profile to merge seamlessly with the terrain while simultaneously opening to distant views and providing crucial protection from the region's harsh winds and intense sun. This project has garnered significant recognition, including the 2022 Texas Society of Architects Design Award and its inclusion in Dezeen's Top 10 Houses of 2022.

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Architectural Design, Building Enclosure, Building Science, Environmental Design, Healthy Home, High Performance Homes, HVAC, Indoor Air Quality, Mechanical Design, Natural Building Material, VentilationPositive EnergyMarfa Ranch architecture, applied building science, Chihuahuan Desert environment, Lake Flato Architects, residential project design, courtyard layout, regional architectural traditions, low profile design, Bob Harris (Lake Flato), spareness of design, Texas Society of Architects Design Award, Dezeen Top 10 Houses of 2022, climate-responsive architecture, vernacular architecture, thermal mass, passive cooling, rammed earth walls, modern building science, MEP engineering, building envelope consultants, Positive Energy (MEP firm), human-centered design, healthy spaces, comfortable spaces, resilient spaces, building envelope, MEP systems, integrated design approach, thermal mass definition, specific heat capacity, diurnal temperature ranges, thermal lag, R-value, moisture resilience, Portland cement stabilization, compressive strength, longevity of rammed earth, hydrophobic additives, drainage, slab edge, moisture management, thermal conductivity, moisture content, hygric buffering, density of rammed earth, thermal lag hours, compressive strength of rammed earth, lifespan of rammed earth, R-value of insulated rammed earth, rammed earth wall performance attributes, air barrier, air pressure differences, energy loss prevention, moisture issues prevention, interstitial condensation, indoor air quality, controlled ventilation, mechanical ventilation, Energy Recovery Ventilators (ERVs), Indoor Air Quality (IAQ) definition, IAQ impacts on health, IAQ pollutants (particulate matter, VOCs, combustion byproducts), ASHRAE standards, green-certified buildings, cognitive function, passive building strategies, ventilation strategies, filtration strategies, humidity control strategies, source control strategies, MERV rating, whole-house fresh air systems, local exhaust systems, humidity range, low-VOC materials, combustion safety, holistic MEP design, hydronic heating system, VRF heating/cooling system, resilient design, sustainable water management, water scarcity, groundwater contamination, water conservation, greywater capture, onsite water storage, adaptive reuse (water tank to pool), rainwater collection, building science principles, durable wall assemblies, Energy Recovery Ventilators (ERVs) for IAQ, early collaboration between architects and engineers, healthier buildings, resilient buildings, positive Energy's mission, Kristof Irwin
The 5 Principles of a Healthy Home

This blog post will present a foundational framework for architectural practice, emphasizing the profound impact of building design decisions on human health and well-being. Moving beyond conventional priorities of aesthetics and initial construction costs, which are unfortunately all too common and mundane in our modern era, this post introduces and explores "5 Principles of a Healthy Home." These principles offer a holistic approach to achieving superior indoor environmental quality (IEQ) and long-term building durability. By understanding and integrating these foundational building science concepts, architects are empowered to design spaces that actively promote the health, cognitive function, and restorative sleep of occupants, thereby elevating their role to advocates for human thriving.

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Architectural Design, Building Enclosure, Building Science, Dehumidification, Filtration, Healthy Home, High Performance Homes, HVAC, Indoor Air Quality, Mechanical Design, VentilationPositive EnergyBuilding design and human health, indoor environmental quality (IEQ), principles of a healthy home, architects as advocates for human thriving, aesthetics vs. first cost in construction, indoor air quality, structural resilience, occupant well-being, human thriving, time spent indoors, invisible threats in indoor environments, particles, gas-phase pollutants, bioaerosols, physiological functions, cognitive functions, epigenetic changes, prenatal gene regulation, indoor air pollutants and gene expression, impact of air quality on cognitive abilities, decision-making, CO2 levels and cognitive performance, impact of air quality on sleep, particulate matter and nitrogen dioxide, sleep disturbances, building enclosure, moisture transport, water management, deflect, drain, dry principles, water-resistive barrier (WRB), flashing details, air barrier, insulation layer, vapor barrier, air leakage, air movement and water vapor transport, material selection and indoor air quality, toxic air pollutants, flame retardants, formaldehyde, chromated copper arsenate (CCA), lead, polyvinyl chloride (PVC), phthalates, dioxins, isocyanates, crystalline silica, air distribution system, flex duct, duct board, fluid dynamics, metal ductwork, air mixing, pollutant removal, indoor pollutants: particles, gases, particulate matter (PM), PM2.5, PM10, ultrafine particles, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), bioaerosols: bacteria, viruses, protozoa, fungal spores, archaea, dust mites, active sources of indoor pollutants, cooking, showering, indoor combustion, air fresheners, personal care products, passive emissions, plasticizers, perfluorinated chemicals (PFAS), antimicrobials, six classes of harmful chemicals, dust as a pollutant reservoir, ventilation vs. air leakage, exhausting pollutants, supplying fresh air, ASHRAE Standard 62.1, ASHRAE 62.2, local exhaust: kitchen and bathroom, range hood, CFM (cubic feet per minute), whole-building fresh air, heat recovery ventilators (HRVs), energy recovery ventilators (ERVs), humidity control, excess moisture, mold growth, dimensional instability, VOC emissions, damp environments and health impacts, respiratory issues, 40-60% RH range, energy codes and latent loads, dehumidification needs, vapor compression dehumidifiers, desiccant dehumidifiers, particulate matter filtration, MERV ratings, HEPA filters, active air cleaning technologies, ozone, mechanical filtration.
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.

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Code, Building Science, Electrification, Healthy Home, High Performance Homes, HVAC, Phius, Passive HousePositive EnergyPhius passive building standards, US construction market, code-built houses, energy efficiency, operational energy consumption, indoor air quality, durability, resilience, extreme weather events, power outages, Phius certified projects, square footage, sustainability goals, Phius certification programs, net-zero energy buildings, continuous insulation, airtight building envelope, high-performance windows and doors, heat- and moisture-recovery ventilation, minimal space conditioning systems, Phius CORE, Phius ZERO, Phius REVIVE 2024, deep energy retrofits, climate-specific standards, US building codes, decentralized regulatory framework, International Code Council (ICC), National Fire Protection Association (NFPA), model building codes, International Energy Conservation Code (IECC), Home Energy Rating System (HERS) Index, ENERGY STAR certification, building permits, single-family homes, multifamily projects, commercial buildings, market penetration of Phius, certification growth trends, energy savings, construction costs, indoor environmental quality, thermal comfort, natural disasters, factors influencing Phius market adoption, regulatory endorsement, decarbonization, training programs, professional certification, long-term cost savings, financial incentives, Qualified Allocation Plans, perceived higher upfront costs, familiarity with passive building principles, specialized materials, traditional construction practices, future outlook for Phius, zero-carbon built environment.
The Case for Dedicated Dehumidification In Sealed Attics

Modern building design increasingly embraces sealed attic construction as a strategy to enhance energy efficiency and improve air leakage control, particularly beneficial for the performance of HVAC ductwork. This approach, where the attic space is brought within the building's thermal and air control envelope, fundamentally alters the moisture dynamics compared to traditional vented attics. While offering significant advantages, sealed attics introduce unique moisture challenges that demand precise and active management to prevent long-term durability issues and maintain superior indoor air quality.

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Recirculating Hoods and Indoor-Air Quality

A few years ago, Fine Homebuilding published a very energy-efficient house that had a recirculating range hood. The reason for the recirculating hood was to avoid punching an additional hole in the air barrier and to avoid the need for makeup air, if my memory serves me. Now I’m faced with a similar decision. Seems recirculating hoods won’t remove moisture from the kitchen—do they at least do an adequate job of filtering the air?

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Designing Healthier Homes by Eliminating Fossil Gas Appliance Emissions

Architects, as the primary designers of our built environment, hold a profoundly influential position in shaping the health and well-being of building occupants. Beyond the critical considerations of aesthetics, structural integrity, and energy performance, a deep understanding of the invisible forces at play within a building's envelope is increasingly paramount. This report aims to equip architects with the essential knowledge to proactively design for superior indoor air quality (IAQ), particularly concerning emissions from common household gas appliances. The decisions made during the design phase, from material selection to mechanical system integration, directly influence the indoor environment and, by extension, the health outcomes of those who inhabit these spaces. This effectively positions architects as critical guardians of public well-being within the built space, expanding their traditional role to encompass a vital public health responsibility.

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Indoor Air Quality, HVAC, Electrification, Architectural Design, Building Enclosure, Code, Filtration, Healthy Home, High Performance Homes, VentilationPositive EnergyDesigning healthier homes, eliminating fossil gas appliance emissions, indoor environmental quality, architect's role, indoor air quality, gas appliances impact on home health, combustion byproducts, hazardous air pollutants, synthesizing scientific findings, actionable strategies for architectural practice, pollutants emitted by gas appliances, health effects, design and engineering solutions, fundamentals of indoor air quality, source control, ventilation, filtration, temperature and relative humidity levels, building as a dynamic system, geographic site, local climate, physical structure, HVAC, construction techniques, contaminant sources, occupants' activities and behaviors, air exchange pathways, mechanical ventilation systems, infiltration, air pressure differences, building envelope, "Building Tight, Ventilate Right" imperative, energy consumption, pollutant concentration, energy efficiency, ventilation strategies, indoor air pollutants exceed outdoor levels, internal pollutant sources, "concentration trap", managing and removing internal contaminants, key pollutants from gas appliances, nitrogen dioxide, carbon monoxide, particulate matter, volatile organic compounds, moisture, respiratory irritation, asthma exacerbation, infection risk, decreased lung function, fatigue, chest pain, impaired vision, headaches, dizziness, confusion, nausea, DNA damage, mortality, transmission of airborne pathogens, organ damage, allergic reactions, cancer, dampness, mold growth, electric coil burners, high-dose exposure, pulmonary edema, diffuse lung injury, bronchitis, ambient air quality standards, carboxyhemoglobin, unvented gas space heaters, gas stoves, back-drafting, angia, poor ventilation, ultrafine particles, respirable particulate matter, cooking emissions, airborne particles, pathogens, respiratory aerosols, formaldehyde, benzene, unburned natural gas leakage, environmental tobacco smoke, automobile exhaust, sensory irritation, carcinogens, moisture load, human respiration and perspiration, bathing, washing, plants, pets, appliance selection, all-electric homes, electronic ignitions, proper appliance installation and maintenance, ducted range hoods, capture efficiency, airflow requirements, multi-family homes, whole-house ventilation strategies, tighter building envelopes, backdrafting risks, make-up air systems, targeted spot exhaust, bathroom fan, high-efficiency filtration, MERV-13, infectious aerosol exposure, cost-benefit analysis, air cleaning, indoor particle concentrations, semivolatile organic compounds, monitoring and alarms, carbon monoxide alarms, advanced IAQ monitors, PM2.5 sources, collaboration with MEP engineers, certified technicians, health impacts, continuous leakage, moisture byproduct, all-electric transition, building a healthier future, works cited, RMI, ASHRAE, EPA, LBNL, ventilation and air cleaning, envelope leakage, hazardous air pollutant emissions, residential ventilation requirements.
Navigating the HVAC Refrigerant Transition and the Promise of Hydronic Systems for Future-Ready Architecture

The global heating, ventilation, and air conditioning (HVAC) industry is undergoing a significant transformation driven by the phasedown of high-Global Warming Potential (GWP) refrigerants, primarily Hydrofluorocarbons (HFCs). This shift, mandated by international agreements like the Kigali Amendment and domestic legislation such as the U.S. American Innovation and Manufacturing (AIM) Act, presents both substantial challenges and unique opportunities for the Architecture, Engineering, and Construction (AEC) industry.

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Heat Pumps, HVAC, High Performance Homes, Indoor Air Quality, Electrification, Building Enclosure, Architectural Design, CodePositive EnergyHVAC refrigerant transition, high-Global Warming Potential (GWP) refrigerants, Hydrofluorocarbons (HFCs), Kigali Amendment, U.S. American Innovation and Manufacturing (AIM) Act, supply chain disruptions, refrigerant costs, technical training, mildly flammable refrigerants, hydronic systems, air-to-water heat pumps, ground source heat pumps, water as heat transfer medium, building performance, global HVAC refrigerant landscape, Montreal Protocol, ozone-depleting substances (ODS), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), HFC phasedown, U.S. ratification of Kigali Amendment, HFC consumption reduction, global warming mitigation, low-GWP technologies, HFC Allocation Program, Allocation Framework Rule, GWP limit of 700, R-410A systems, refrigerant leak detection, refrigerant reuse, reclaimed and recycled HFCs, leak repair, recordkeeping, reporting, labeling, automatic leak detection (ALD) systems, reclaimed HFCs for servicing, cost of compliance, A2L-class refrigerants, R-454B, R-32, refrigerant flammability, safety protocols, certified HVAC technicians, ACCA A2L training, ASHRAE Standards, UL Safety Standards, refrigerant types comparison, R-22, R-290 (Propane), R-744 (CO2), R-717 (Ammonia), AEC industry challenges, project timelines, supply chain constraints, refrigerant shortages, material scarcity, A2L safety training, regulatory compliance and enforcement, EPA regulations, state-level regulations, equipment availability and compatibility, refrigerant recovery machines, hydronic system types, radiant systems, baseboard heating, chilled beam systems, snow melt systems, AWHPs principles, AWHPs benefits, GSHPs principles, GSHPs advantages, ground loop, ground temperature stability, GSHP design considerations, GSHP energy savings, Investment Tax Credit (ITC), Inflation Reduction Act (IRA), technology neutral homes, renewable electricity sources, building envelope performance, HVAC system sizing, thermal insulation, high-performance glazing, air leakage, whole building design, commissioning, thermal performance, airtightness, passive building principles, Phius (Passive House Institute US), continuous insulation, thermal bridging, condensation prevention, super-insulation, minimal space conditioning system, moisture management, dew point temperature, latent loads, dedicated outdoor air system (DOAS), dehumidification, smart controls, material selection for radiant cooling, wall design for hydronics, floor design for hydronics, ceiling design for hydronics, building physics, heat transfer processes, moisture dynamics, indoor air quality, economic benefits of hydronic systems, operational cost reductions, energy efficiency, high-efficiency circulator, VRF system comparison, DX unit comparison, water source heat pumps, lifespan of hydronic systems, maintenance costs, environmental impact of hydronics, decarbonization, solar thermal, geothermal energy, strategic design for sustainable HVAC.
Rethinking Moisture Control: The Primacy of Air Tightness Over an Outdated Fixation on Vapor Barriers in Building Envelope Design

For decades, the architecture and construction community has engaged in a persistent debate surrounding the role and necessity of vapor barriers in building envelope design. This discussion, while touching on critical aspects of moisture control, has often been characterized by an overemphasis on the ability of specific materials to resist vapor diffusion, sometimes to the detriment of addressing more significant moisture transport mechanisms. Within the building science community, however, the principles governing moisture movement are largely considered settled science. It is well-established that air leakage, rather than vapor diffusion, is the predominant pathway for moisture transport through most wall assemblies.

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The Damp Deception: How a Well-Intentioned Code Change is Fostering Mold in New Homes

The promise of a new home often includes visions of a healthier, more energy-efficient living space. However, a subtle yet significant regulatory shift in U.S. building codes, particularly affecting hot-humid climate zones, may be inadvertently undermining this very promise. Before 2021, residential ventilation requirements were often loosely enforced; homes were typically required to have a ventilator, but the actual volume of air exchanged was not mandated to be measured. This frequently led to systems being ineffectively installed or even "sabotaged" by HVAC contractors, rendering them inoperable or improperly configured from the outset. Consequently, many homes, even in that period, did not achieve consistent fresh air exchange. Compounding this, most residential HVAC systems lacked any form of supplemental or dedicated dehumidification, a feature that building science experts have increasingly recognized as crucial, especially for high-performance homes in moisture-laden environments.

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Ductwork for a Retrofit ERV

We have had a number of customers ask for energy recovery ventilation (ERV) in their existing homes. Can we use the existing furnace ductwork? If not, what size and type of ducts can be used?

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The Fine Homebuilding Interview: Kristof Irwin

By Aaron Fagan, Kristof Irwin, originally published in The Fine Homebuilding Magazine, Issue 300 - July 2021

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Wildfires, SARS-CoV-2, & Portable Room Air Cleaners

If wildfires are to be a more frequent and intensive aspect of life in the US and future pandemics are not out of the question, how do homeowners start addressing their air quality to improve the safety their homes can provide? We’ve heard from many clients, friends, and family members in wildfire affected areas asking questions like this so we thought it was worthwhile to expand our air quality focus beyond just SARS-CoV-2 and provide some meaningful content that can serve wildfire sufferers as well. Enjoy some applied scientific guidance on the topic of portable room air cleaners (or PRACs).

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