Friday, November 1st, 2013 by Brian Stewart
Have you ever heard someone say that houses need to breathe? Have you ever thought about what that means? Do our houses have lungs? Do they get bronchitis? Can our houses swim under water if they wear scuba gear?
Your house does not need to breathe. You need to breathe and so do your gas burning combustion appliances. These include such things as a gas furnace, water heater, fireplace, kitchen range, or clothes dryer. Without enough air to support the combustion process, these appliances will burn inefficiently and can produce dangerous levels of carbon monoxide.
When people say your house needs to breathe, they are really saying your house needs ventilation. This means fresh air in and stale air out. Fresh air coming in means oxygen for you and your furnace. Stale air out means that combustion byproducts and people byproducts aren’t trapped in the house.
Ventilation also has other positive effects. Ventilation provides one means for excess moisture to get out of your home without contributing to mold, mildew, or just plain uncomfortable humidity. It can make the house smell better. It can improve indoor air quality.
Ventilation does many things for your home but all of them are not good. Air coming in is not always “fresh”. Air coming into the house can bring dust, pollen, mold spores and all kinds of other pollutants. It can make humidity worse and make the house smell bad. It can make indoor air quality worse.
A penalty we all pay for the good effects of proper ventilation is wasted energy. The airflow standard for each home is calculated based on the size of the house and the number of occupants. Your home may have the right amount of ventilation, it may have too much, or too little. When a house has too much ventilation, we say it is “leaky” and wasting energy.
An energy audit will include a blower door test to determine how much ventilation your home has. If you have more than the airflow standard, you are wasting energy. This waste can be eliminated by air sealing some (but not all) of the holes and cracks, large and small, to reduce or eliminate the excess ventilation.
In the end, ensuring your house has the right amount of ventilation can make a huge, positive difference in your energy usage, comfort, safety, and indoor air quality. If you want to say your house needs to breathe, go ahead. Just make sure it doesn’t breathe too much.