A blower door is a diagnostic tool designed to measure the air tightness of buildings to help locate air leakage areas. A blower door consists of a calibrated fan for measuring an airflow rate, and a pressure-sensing device to measure the air pressure created by the fan. The combination of pressure and fan-flow measurements is used to determine the building’s air tightness. The air tightness of a building is useful knowledge when trying to increase energy conservation, decrease indoor air pollution, or control building pressures.

     A basic blower-door system includes three components: a calibrated fan, a door-panel system, and a device to measure fan flow and building pressure. The blower-door fan is temporarily sealed into an exterior doorway using the door-panel system. The fan is used to blow air out of the building, which creates a negative air pressure difference between inside and outside. This pressure difference forces air through all holes and penetrations in the building enclosure. The tighter the building (e.g. fewer holes), the less air is needed from the blower door fan to create a change in building pressure. 

   There are several places that are typical culprits for air leakage.  The first and biggest offender is generally high hat lighting.  The typical builder just cuts a hole in the drywall and inserts the light.  Often, there will be anywhere up to a quarter inch gap around the light that can be hidden by the lights trim ring.  The supply grills for you AC system are often sealed improperly.  The other major places you will find leakage is in your duct system itself.  Over time, the connections that sealed your duct work together break down and need to be re-sealed.  

     As always, for assistance with these matters, contact us @ www.artplumbingandac.com