What does a blower door test typically measure in a building?

A blower door test is specifically designed to measure air leakage pressure in a building. During this test, a blower door fan is installed in an exterior doorway, creating a pressure difference between the inside and the outside of the building. This helps to quantify the amount of air that leaks in and out of the building envelope, which is crucial for understanding the building's airtightness.

The results from the blower door test indicate how well a structure retains heated or cooled air, thereby influencing energy efficiency and comfort levels within the space. Understanding air leakage is vital for identifying areas that may need weatherization or other improvements to enhance the overall energy performance of the building. While temperature differences, energy efficiency ratings, and insulation effectiveness are all important factors in building performance, they are not directly measured by a blower door test. Instead, this test focuses on evaluating how much air escapes or enters, which directly impacts energy consumption and indoor air quality.