A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings in the home. The TIG auditor may use a smoke stick to help further detect air leaks. These tests determine the air infiltration rate of the home and where leaks are occurring.

Additionally, a blower door test can also help determine air leakage or disconnections in supply ducts and returns as well as lack of insulation value.

You can watch a detailed overview of what a blower door test includes in the videos at the right of this page. The blower door test is the final part of a complete home energy assessment which includes safety testing for CO levels, proper ventilation, adequate insulation levels and more.