Air Source Heat pumps are like a cross between Geothermal and Central air conditioning. They don’t work exactly like either one, but incorporate some of each. Heat pumps are a single system used to both heat AND cool a home. Like central air conditioning, an Air Source Heat Pump has a condenser that sits outside of the home, which is largely identical to an air conditioning condenser. In the summer when it is warm, just like a central air conditioner, the heat pump removes the heat in the home and expels it outside, and then brings cooled air back into the home via refrigerant.
However, in the winter, the Heat Pump works like a Geothermal unit (which itself is a type of Heat Pump), in that it takes heat from outside (yes there is heat energy out there!) and brings it into the home. The major difference here is that while Geothermal utilizes heat energy from underground, Air Source Heat Pumps utilize heat energy from the air itself. This makes for a very efficient form of heating and cooling. However, if you live in a cold weather area like our own, these units can only sustain heat to a certain temperature. For this type of situation, it is best to utilize this system with a conventional back-up system, such as a furnace or boiler, to ensure the home stays heated at all temperatures.