A blower door test is a measurement of your home’s air leakage. Home air leakage describes the gaps and holes in your building envelope where indoor air escapes or where outdoor air can enter. This is important because the more leaks there are, the harder your home has to work to heat or cool itself. In very leaky homes, money and energy are being wasted on heating or cooling air that does not stay.
The setup to conduct a blower door test fits a fan to a doorway to depressurize your home and draw in air through the cracks or gaps in the structure. The pressure gauge measures the rate of airflow required to keep your home at a constant pressure. The results are used to calculate the rate of air leakage in your home.