How to breathe easy about your home’s air quality

Dear Pat and Brad: I read your column a few months ago on sealing air leaks, but I’ve heard a home that’s sealed too tight can lead to air quality issues. How can I be sure I have healthy air as I seal air leaks in my home? – Lee

Dear Lee: Sealing air leaks is one of the best ways to make your home energy efficient, and there are steps to ensure your home has an adequate amount of healthy, fresh air.

The average home loses about half its air volume every hour, so it can be sealed considerably (often at a low cost) and still have more than enough healthy air.

Pollutants are the main cause of poor indoor air quality, and the most dangerous pollutant is carbon monoxide (CO). It comes from furnaces, water heaters or stoves that burn natural gas, propane or wood. The problem usually occurs in devices that are old, in need of repair, or installed or operated in a manner that prevents clear, unobstructed supply and exhaust of combustion air.

Moisture in the air can be considered an indoor pollutant because mold and dust mites thrive when relative humidity is above 60 percent. One sign your home is sealed too tight is window condensation, which happens if moist air doesn’t exit the home at an adequate rate.

Pollutants can cause physical reactions such as coughing or sneezing, but carbon monoxide causes severe reactions, such as headaches, dizziness, nausea, shortness of breath, confusion, blurred vision or loss of consciousness.

Eliminate pollutants

According to the Environmental Protection Agency (EPA), the first strategy to ensure healthy indoor air while increasing your home’s energy efficiency is to eliminate or reduce the source of pollution. The first pollutant to eliminate is carbon monoxide. A combustion furnace should be inspected and serviced regularly by a professional. If you have any combustion appliances, it is critical to install CO detectors and replace them every five to seven years.

Determine if you live in an area with radon by checking EPA’s radon map. Radon is the second leading cause of lung cancer. Radon tests are not expensive, and your local health authorities can provide more information. If radon levels are too high, hire a professional to install a system to divert radon gas outside of your home.

A few additional pollutant reduction measures to consider: never smoke tobacco inside, run exhaust fans in the bathrooms and kitchen after use, store toxic cleaning and painting products outside, and never idle a vehicle in an attached garage, even for a minute.


Your home probably has more than enough natural ventilation from outside air leaking into the home. If you suspect this isn’t adequate, hire an energy auditor to do a blower door test.

Experts recommend sealing the home as tight as possible and using mechanical ventilation to ensure a consistent and adequate supply of outside air. The most energy efficient ventilation system is a heat recovery ventilator (HRV), which pulls in outside fresh air and captures heat from indoor air before it is exhausted to the outside.

Clean the air

Change your furnace filter at least once every three months and keep your furnace supply and return air registers free of obstructions. If rooms do not have an air return, keep the doors open. There are several home air cleaning systems available—some are effective and some are not. The EPA offers an online guide:

We hope these suggestions will be helpful as you seal air leaks in your home and enjoy fresh, healthy indoor air.