One of the only ways to actually measure the tightness of a building is by blower door testing. This testing is a final exam, so to speak. It usually occurs when all air sealing has been completed and acts as the measured result for that home.
A large fan and support-bracket assembly is temporarily installed in an open door of the home. The operator takes a series of pressure and airflow measurements. An analysis of the data indicates the total leakage area of the home. From this, the rate of air leakage in air-changes per hour can be estimated.
You may also want a test during construction while many of the seals are still accessible. This allows you to find air leakage sites that were missed or not adequately sealed. It’s much easier to fix problems before carpets, pads and baseboards are installed. While the home is depressurized by the blower door, it is easy to identify the areas where air is rushing in. They can be identified by means of a small smoke-producing device (a “smoke-stick”) or even your hand. This approach allows you to test and improve the quality of the sealing work. |
