Staying Cool Indoors? Not So Fast — Heat Waves Impact Indoor Air Quality

As temperatures surge across the country and fall looms, homeowners are juggling late-summer weather challenges and back-to-school routines, all while seeking comfort inside their cool homes and buildings. But retreating indoors for relief can quietly worsen an often-overlooked consequence of lingering heat waves and early fall temperature swings: declining indoor air quality.

That’s why expert, Molly McCrory of the indoor air quality team at Ferguson—one of the nation’s top distributors of HVAC equipment and supplies — says this transitional period is a good time to address your home’s air systems.

“Indoor air is, on average, five times more polluted than outdoor air,” said McCrory. “Most people think of heat waves as an outdoor health issue, but it is important to address air quality if homeowners are spending more time indoors.”

McCrory shares the top indoor air quality challenges to watch now, and actions homeowners can take to get ahead:

1. Humidity spurs allergen growth.

Indoor humidity isn’t just a comfort factor; higher moisture levels create ideal conditions for hidden mold and mildew growth. Mold can release spores that can trigger allergies and asthma.

• Monitor humidity levels: Keeping indoor humidity between 30% and 60% reduces the risks associated with mold and mildew growth.
• Consider a dehumidifier: While portable units help, they often require frequent emptying. A whole-home dehumidifier installed by an HVAC professional offers lower maintenance and greater efficiency. It can also help lower energy bills, as drier air feels cooler and more comfortable, which reduces the need for the HVAC system to run as often.

2. Heat increases pollutants.

Beyond the usual accumulation of dust and household pollutants, warm temperatures can cause materials like carpets, furniture and paint to release gases into the air. In wildfire-prone regions, summer brings the added risk of smoke particles in the air.

• Replace air filters: “It’s a simple, affordable and effective way to clean the air,” McCrory said. Think of it as late summer maintenance that protects your air into the colder months. While it may be tempting to choose a higher-rated filter, she advises consulting a contractor first. “A tighter filter collects more particles, but it can also make the system work harder. HVAC systems are delicate, and the last thing homeowners want during a heat wave is a motor failure.”
• Install a UV bulb: These lights are mounted inside an HVAC system to neutralize germs, mold and microscopic particles.
• Consider air ionization: An ionizer is device that uses negative ions to remove certain airborne particles from the air; simply put, it acts like a static magnet for dust. “Ions don’t like to be alone,” McCrory said. “They cluster on airborne particles, making it easier for the filtration system to remove them.”

3. Sealed homes trap pollutants.

To keep cool air inside, people often seal windows and doors tightly during heat waves. While that improves efficiency, it also reduces fresh air exchange and traps indoor pollutants.

• Balance the ventilation: “The old adage is true: ‘Dilution is the solution to pollution.’” McCrory recommends adding balanced ventilation to bring fresh, purified air into the home and diluting the polluted air.
• Schedule HVAC cleaning and tune-ups: Poorly maintained systems can circulate dust, mold and bacteria. “Getting the coils cleaned - that’s what the air passes over to cool your space - is one of the simplest and most effective steps homeowners can take,” McCrory said.

McCrory added that there is rarely a single reason for decreased air quality, so that means there is rarely a one, perfect solution.

“Your best bet is to engage an HVAC pro now – while it’s still summer – who can create a solution and future-forward plan that keeps your home’s air healthy, comfortable and efficient as the temperatures flux and the seasons change.”

For Media Inquiries

Molly McCrory is available for interviews to discuss how homeowners can prepare their air systems now — ensuring healthier, cleaner air as seasons change.