Attics can let worst parts of outdoors into your house

The U.S. Environmental Protection Agency says that the air in your home can be two to five times more polluted than the outdoor air.

When the wind blows, your house is subject to its effects. It creates a positive pressure on the side of your home that it’s hitting directly, and at the same time, it’s literally sucking air out of the opposite side.

All homes leak air, at least a certain amount. We need them to leak some air, coming in and going out, so that the air inside doesn’t get depleted of oxygen. We need fresh air.

However, in many cases the air that is leaking into the home is from unhealthy areas that can bring in insulation fibers, dirt, dust, allergens, volatile organic compounds, viruses, and bacteria.

While sealing around doors and windows can definitely help reduce energy costs, it can also increase the amount of unhealthy air being introduced into the home. The air that leaks in around windows and doors is usually clean, fresh air, especially in the winter months. There are other leak areas that are more costly to our health and comfort and even energy costs than windows and doors.

The worst air leaks are those from ductwork. The second-worst are from attic spaces. Not only do they let in insulation fibers, but also allergens, rodent urine, feces and other air pollutants.

The attic is directly connected to the outdoors through attic vents. Things like recessed lights; unsealed attic hatches or doors; building cavities connected to basements; plumbing chase ways; and staircases are all culprits in causing attic air to leak into the home. This air in the summer season is very hot and full of humidity — and it’s just the opposite in the winter.

The next-worst offenders are crawl spaces and attached garages. Crawl space leaks can allow stale, unhealthy air, as well as unconditioned air, to seep into the home. Attached garages can leak deadly carbon monoxide and unconditioned air into the home also. Sealing the air leaks in your home not only makes sense from an energy savings standpoint, but for health and comfort as well.

Joel Wensley is a licensed mechanical contractor in the state of Michigan, a member of the Comfort Institute, and is also the president of Mechanical Heating & Cooling in Dearborn Heights.