BLOWER DOOR TEST
Blower Door Testing measures how much air is moving into or out of your home through the thousands of small gaps in the building envelope. The infiltration of hot, humid air into your house in the summer and the exfiltration of heated air in the winter - both make your air conditioner/heater run longer and cost you money. Air leakage testing measures the amount of this leakage and shows where it is.
This is a simple test. A "blower door" apparatus is installed in an exterior door. The fan in this door sucks air out of the house until the pressure difference between inside and outside is 50 pascals. The volume of air that is moving through the fan to create this pressure difference is measured by a differential pressure gauge. The air leaving the house is exactly the same as the air "leaking" into the house to replace it.
The test measures the "leakiness" of your house - how much air leaks into and out of it due to differing air pressures indoors and outdoors. Energy is lost in summer as hot, humid air comes into the house, increasing the load on your air conditioner. In winter, heated air escapes to the outdoors, increasing the heating load. The Blower Door test measures the amount of air leaking into/from your house - and also reveals the location of these leaks, so they can be sealed.
When applying spray polyurethane foam insulation to an existing home's attic, the Blower Door test reveals where gaps in the foam exist, helping installers to better seal the attic. This reduces the possibility of moisture problems.