Over the past 20 years, we have begun to build tighter and tighter construction. What does tight mean? Before air conditioning we opened our windows much of the year ventilating the indoor air. Now, we adjust the thermostats to find a comfortable level, almost never opening our homes. We now use house wrap, caulk, exterior sheathing, and forced air systems to make our houses more energy-efficient. All of these things contribute to our indoor air quality – positive and negative. Our houses don’t leak air like they used to, our windows are better built, and our air is conditioned mechanically, circulating the same air around the house through filters that do little more than prevent birds and small dogs from going through them.
I am fully supportive of the concept of air tight and vapor permeable construction for our mixed humid climate here in Virginia. However, we do need fresh air introduced into our homes to maintain a safe quality indoor air to breath. Many builders take a short cut in the introduction of fresh air into the home. They either count on air leaking through the crawl space and attic into the home or figure you will open windows enough to stay healthy. Many studies have shown that the indoor air in our homes and offices are more polluted than outdoor air, even in a busy downtown at an intersection. We need a quality filtration system on our heating and cooling systems, but also need ducted fresh air for health and comfort. You should know how much air leakage your home has, this should be a common question for any home owner. However, most home owners don’t know if their houses leak enough or too much.
Uncontrolled Air Leakage in the home is not a bad thing assuming you don’t use a heating and cooling system and you don’t mind your fresh air coming from a musty crawl space or a humid dusty attic, or worse, being filtered through the walls of your home that are filled with fiberglass insulation. Air leakage for a healthy home should be hard ducted into your forced air system or through some other controlled ducted air delivery system.
Stay tuned for additional tips in our next blog entry for things to look for to keep your family’s indoor air safe and healthy.