Heat Pump

Run it one direction and it cools like a standard air conditioner, pulling heat out of your home and dumping it outside. Run it the other way and it heats, pulling warmth from the outdoor air and bringing it inside. That reversible trick is what makes a heat pump a single system that both heats and cools by moving heat instead of creating it. The U.S. Department of Energy explains that a heat pump "transfers heat rather than converting it from a fuel, like combustion heating systems." One unit does both jobs.

Because it transfers heat rather than burning anything, a heat pump is very efficient. The DOE notes a properly installed unit "can deliver up to two to four times more heat energy to a home than the electrical energy it consumes," and ENERGY STAR puts the figure at up to three times the electricity used. A heat pump is rated for cooling by SEER2 and for heating by HSPF2, the same scoring family used for high-efficiency AC. An air conditioner cools only; a heat pump is essentially an air conditioner that can also run backward to heat.

For example, Arizona's mild winters are a good fit for a heat pump. A Fountain Hills home rarely sees a hard freeze, so the system spends most of the year cooling and handles winter heating efficiently from outdoor air, often without a gas furnace at all. A mini-split is one common type of heat pump, useful for a casita or an addition where running ductwork is impractical.

A heat pump is not a furnace and not just an AC. It is one system that flips between the two by reversing the direction it moves heat. For a desert home that cools far more than it heats, that combination of summer efficiency and simple winter heating is why heat pumps are common here. We size them to the home with a Manual J load calculation, not by rule of thumb.