Ventilation for Designing Better Buildings

Mold & Dust Mites: How Your Basement Impacts Home Air Quality

Posted by Sarah Lozanova

Mar 24, 2017 9:05:00 AM

Did you know that many of the indoor air quality issues in a home originate in the crawl space or basement? Unfortunately, basement air is frequently the most compromised air in the house, and contaminants commonly spread to the first floor.

Many basements and crawl spaces have humidity issues that encourage mold and dust-mite population growth. Mold spores are most problematic when mold grows inside the home, creating allergens and irritants. Indoor air quality issues are common in both finished and unfinished basements.

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Standard gypsum wallboard can act like a sponge by absorbing moisture and can harbor mold, which can continue to grow and release spores over time. Unfinished basements often contain a substantial amount of debris, dirt, and dust, encouraging fungal growth. Improperly vented dryers can cause excessive moisture to develop, promoting mold growth.

Household chemicals, pesticides, and paints are often stored in basements, slowly releasing pollutants into the air that can end up in the living areas of the home. Atmospheric hot water heaters rely on convection to exhaust hot gases and are also relatively common. When they malfunction, gases can enter the mechanical room, contaminating the home. These air quality issues are important to address to promote health and well-being.

Basement Air Permeates the First Floor

In many homes, air from the basement or crawl space rises and enters the first floor, compromising indoor air quality. Exhaust fans in the home cause air to exit the home, requiring makeup air to then enter elsewhere. This negative pressure can cause basement air to infiltrate the living spaces above. This can also cause the flue on an atmospheric hot water heater to backdraft, especially in tightly constructed homes.

Because warm air rises, temperature differences between the house interior and exterior can cause upward movement of air. This can cause outside air to enter through the basement and rise up into the home, bringing pollutants with it.

Balanced Ventilation Systems

Installing a balanced ventilation system, such as an energy recovery ventilation system or a heat recovery ventilation system, avoids creating negative pressure because it supplies and exhausts equal quantities of air. This can help prevent pulling of pollutants from attached garages and basements into the living spaces of the home.

Zehnder heat recovery ventilators filter the intake air entering the home, removing many airborne pollutants. These systems provide a constant stream of fresh air while removing stale air, boosting indoor air quality throughout the home.

How to Improve Indoor Air Quality

Topics: IAQ