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What the Pros Want Homeowners to Know About Indoor Air Quality
Reading time: 4 minutes
Comfort
Your Home Might Be Too Sealed for Comfort
Over the past few decades, the way homes are built has fundamentally changed. Builders and engineers have worked hard to improve energy efficiency, making homes tighter, better insulated, and more resistant to drafts. From the outside, this seems like great news. In many ways, it is.
But these improvements also come with an unintended consequence: indoor air doesn’t move like it used to. In many modern homes, the air can stagnate, trapping pollutants inside and reducing overall indoor air quality (IAQ). If you’ve ever walked into a home and noticed that the air feels heavy or stale, that’s exactly the problem we're talking about.
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From Drafty to Airtight: The Shift That Created an IAQ Dilemma
Historically, homes weren’t sealed very tightly. Gaps around windows and doors, less effective insulation, and single-pane glass meant that fresh outdoor air could easily flow in even when homeowners didn’t intend it. While this was inefficient from an energy standpoint, it allowed pollutants to naturally dilute and escape.
Today, with high-performance building envelopes, advanced insulation, and weather-sealed windows, homes are designed to minimize energy loss. Central HVAC systems are often designed to recirculate air efficiently, not necessarily to bring in fresh air. In most homes, fresh air enters only when a door or window is opened. Often that’s not nearly enough.
What’s in the Air Indoors?
Indoor air may contain a cocktail of pollutants, many of which are invisible and odorless. These include:
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Volatile organic compounds (VOCs) from cleaning products, furniture, paint, and personal care items
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Combustion byproducts from cooking, fireplaces, or gas appliances
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Particulate matter including dust, pollen, and pet dander
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Excess humidity, which can encourage mold and mildew
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Viruses and bacteria in poorly ventilated spaces
According to the U.S. Environmental Protection Agency (EPA), Americans spend about 90% of their time indoors, and indoor air can be two to five times more polluted than outdoor air, even in urban areas [EPA, 2023].
Why Professionals Are Prioritizing Ventilation
Builders, engineers, and HVAC contractors increasingly agree: a well-sealed home must include a strategy for ventilation. This doesn’t mean opening the windows every day. Instead, it often means integrating mechanical ventilation systems technology that moves stale indoor air out and brings fresh, filtered air in.
There are several approaches, depending on the climate, home size, and layout:
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Exhaust-only systems, typically using bathroom or kitchen fans to remove air
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Supply-only systems, which push fresh air in but rely on passive airflow for exhaust
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Balanced systems, like energy recovery ventilators (ERVs) or heat recovery ventilators (HRVs), which exchange indoor and outdoor air in equal amounts, while conserving energy
These systems ensure that indoor air doesn’t just stay in the house indefinitely. Instead, pollutants are removed, and oxygen-rich outdoor air is introduced on a regular basis.
IAQ is increasingly evaluated through a broader lens. Beyond VOCs and pet dander, today’s best practices account for fine particulate matter (PM2.5), CO₂ accumulation, moisture management, and occupant behaviors such as indoor combustion, cleaning routines, and exercise activity.
Mechanical ventilation systems must not only address these variables but do so in alignment with current codes and standards. ASHRAE 62.2 and the IRC now mandate whole-house mechanical ventilation in most new residential construction. Properly selected HRVs and ERVs contribute to compliance while supporting improved HERS scores, reduced infiltration rates, and more consistent indoor conditions across the home.
How Ventilation Supports Comfort, Health, and Performance
Good ventilation isn’t just about air quality. It improves overall home performance:
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Comfort: Removes excess humidity and odors from cooking or showers
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Health: Reduces the risk of asthma, allergies, and respiratory illness
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Durability: Helps control moisture and prevent mold growth in building materials
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Energy efficiency: When paired with energy recovery, mechanical ventilation can help maintain comfort without large energy penalties
For builders and HVAC pros, modern ventilation systems are no longer optional. It is considered best practice. In fact, many codes across North America now require mechanical ventilation in new homes (e.g., the International Residential Code (IRC) and ASHRAE 62.2 standard).
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Next Steps: Tools for Better Indoor Air Quality
Mechanical ventilation bridges the gap between airtight construction and healthy living. It’s not just a matter of meeting code; it’s about creating homes that support long-term comfort, health, and performance. For today’s building professionals, ventilation isn’t a side consideration, it’s essential.
One of the most effective ways to improve indoor air quality in today’s tightly sealed homes is with a balanced ventilation system, especially an energy recovery ventilator (ERV) or heat recovery ventilator (HRV). These systems provide a consistent supply of fresh air while maintaining comfort and reducing energy loss.
There are a variety of options available to suit different home sizes and project types:
FIT Series ERVs: Designed for multi-family homes where space is limited, these compact fresh air appliances offer up to 129 CFM of airflow and feature energy-efficient cores, optional high-efficiency filters, and ENERGY STAR® certified models.
HERO Series HRVs & ERVs: Suitable for both single- and multi-family homes, HERO fresh air appliances deliver up to 252 CFM with advanced features like integrated balancing taps, optional MERV 13 filters, and lifetime core warranties. A new to-port ERV, the HERO 100E, launches June 2025.
ATMO Series HRVs & ERVs: Built for single-family homes, ATMO systems provide up to 300 CFM and include both HRV and ERV options, easy-access maintenance panels, and high-performance cores with ENERGY STAR® models available.
Fresh Air Controls: A wide range of control options are available to make ventilation simple and effective, including TVOC sensors, dehumidistats, and timers (digital, push-button, or wireless).
Learn more about the ECO-Touch® Auto IAQ
Browse the full line of HERO Fresh Air Appliances
From Code Compliance to Everyday Wellbeing
Choosing the right ventilation system is about more than ticking boxes on a checklist. It’s an investment in healthier indoor spaces, spaces where people can breathe easier, live more comfortably, and benefit from the full value of high-performance construction. Whether it’s a compact ERV for a condo or a high-capacity ERV/HRV for a single-family home, balanced ventilation systems help future-proof the indoor environment.
Sources:
U.S. Environmental Protection Agency (EPA). "Indoor Air Quality." Last updated 2023. https://www.epa.gov/indoor-air-quality-iaq
ASHRAE Standard 62.2-2022: "Ventilation and Acceptable Indoor Air Quality in Residential Buildings"
U.S. Department of Energy, Building America Program
Healthy Buildings Program, Harvard T.H. Chan School of Public Health
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