Patent ID: 7494524

Claim:
An apparatus for maintaining a desired air pressure inside a home, the home having an HVAC system and an opening to the exterior of the home, said apparatus comprising: a housing having a first fitting and a second fitting and a substantially linear passageway between said first fitting and said second fitting; said first fitting being adaptable for placing said apparatus in air flow communication with the opening; said second fitting being adaptable for placing said apparatus in air flow communication with the HVAC system; a motorized damper connected to said housing; a differential pressure switch/gage in signal communication with said motorized damper; said differential pressure switch/gage having a first port and a second port; said first port being adaptable for sensing a first pressure inside the home; said second port being adaptable for sensing a second pressure outside the home; said differential pressure switch/gage being adaptable for producing a signal in response to a difference between said first pressure and said second pressure; said motorized damper being operable to admit air into the home through said passageway in response to said signal.