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How Does HVAC Power Exhaust Work?

Amy Rodriguez

Large buildings, such as tall skyscrapers, use controlled air conditioning units to keep the inside of the building comfortable for workers. Many components make up these systems, including a powerful fan, called a power exhaust.


Many HVAC systems use power exhausts.

An heating ventilation and air conditioning (HVAC) power exhaust is a dual fan addition to a rooftop air conditioning system. As air is pumped into a building for air conditioning, the pressure builds. To keep the pressure equalized, the power exhaust pumps air out through the return ducts to the outside.


Typically, a small computer controls the function of the power exhaust. The user sets the device for a minimum and maximum pressure preference. As the pressure builds in a building, the power exhaust senses this change and turns on. As the pressure lessens, the exhaust fan is triggered to shut off when the designated pressure is reached.


By having an automatic pressure control, the building stays at a comfortable temperature and pressure level so workers can stay productive. In addition, keeping the pressure steady helps keep more air within the building, saving on energy to run the air conditioning overall.