During a blower door test we use pressure to determine how much air flow enters the building during a given time. The 2009 IECC, 2012 IECC, and all energy star homes are required to have a blower door test. It tells us if the house is too leaky and inefficient or it can even tell us if the house is too tight and ventilation air needs to be introduced. For home owners we highly recommend a blower door test for anyone wanting to improve the efficiency of their home and we include this test in all our audits. We also highly recommend this test if you are building a new home, especially if spray foam is used.
All builders should be actively using a company that provides blower door testing. We highly recommend that all builders contact TPI so we can start testing and advising you on what to expect for the new codes. Some cities have already started making this mandatory and we know what they expect.
Homes are under constant pressure differentials which will suck air into the home or blow air out of a home, which means you are constantly loosing your heated or cooled air. Homes create a natural effect called a stack effect, leaky homes create a stronger stack effect than tight homes. We always recommend making the home as tight as possible and controlling where new air is introduced into the home. Controlling air flow is not just energy efficient but also healthy for the home; it helps control moisture intrusion, high humidity, low humidity, dust, pollen, mold, and prevents rodents and pest from getting in the home. The picture below illustrates what the stack effect does.