The Blower Door is an amazing tool. A home energy auditor or home energy rater can use it to do performance testing by quantifying the infiltration rate of a house. They can also do diagnostic testing with it, by running the Blower Door and walking around the house to find leaks.
Basic Operation. The basic principle of its operation is simple. A powerful fan set temporarily in a doorway creates a pressure difference between the house and the outdoors, usually by depressurizing the house. All the air that the fan blows out of the house is replaced by air coming in through all the leaks. For every cubic foot of air that blows out through the fan, a cubic foot leaks in.
So, all we need to do is measure the amount of air moving through the fan, and, voila, we know how much the house leaks at that pressure. Airflow is measured in cubic feet per minute, and the pressure normally used for this test is 50 Pascals. Hence, the number that everyone who does this testing in the US uses is cfm50.
Building Science News & Trends for 2025
Several years ago, I heard something really interesting at a talk by a self-described futurist. It's an interesting "Futurists,"…
Allison Bailes provided HERS training to me at a recent HERS Rater training course. He is extremely knowledgeable in building science and provided excellent training. He also is very patient and was very concerned about providing the requisite information for his students to not only pass the HERS training curriculum but to ensure that we as HERS raters would be best prepared to execute this training in the field. I highly recommend Allison for training or other services he may provide in the area of building science.