There are two types of blower doors: calibrated and uncalibrated. It is important that auditors use a calibrated door. This type of blower door has several gauges that measure the amount of air pulled out of the house by the fan. Uncalibrated blower doors can only locate leaks in homes. They provide no method for determining the overall tightness of a building. The calibrated blower door’s data allow the auditor to quantify the amount of air leakage and the effectiveness of any air-sealing job.
Preparing for a Blower Door Test
Take the following steps to prepare your home for a blower door test:
Close windows and open interior doors
Turn down the thermostats on heaters and water heaters
Cover ashes in wood stoves and fireplaces with damp newspapers
Shut fireplace dampers, fireplace doors, and wood stove air intakes.