A heat pump works on the basic principle that the sun's heat is always in the air, even in cold air. A heat pump extracts this heat from the outside air and transfers it into the interior of the house by way of the house's internal duct work. This heat is circulated through the ducts by a high-powered fan after it passes over a condensing unit to either add heat to or remove heat from the air.
Heat pumps are best utilized in areas with milder climates. Extreme temperature changes do not allow a heat pump to work adequately. In these climates, individual heating and cooling equipment is recommended. When temperatures are extremely cold, the heat pump is equipped with an auxiliary heat strip that powers on. This strip will produce much more heat than the heat pump alone, but it also costs significantly more to operate.
Heat pumps are economical. The operating costs are less to heat or cool a home than a traditional heater or air conditioner, as long as temperatures remain relatively mild. A heat pump can produce three times more heat or cooling for the same cost than an air conditioner and furnace or boiler. The heat that is produced is also less intense than a traditional heater, so it can be run for a longer period of time while still maintaining a comfortable level of air flow and circulation. An added benefit is that heat pumps physically extract more moisture out of the air than a standard air condensing unit. This means that humidity can be controlled better during the late summer months. Another consideration is that the footprint of a heat pump is smaller, because the heating and air conditioning features are contained all in one unit.
Although there are many benefits to selecting a heat pump, the initial installation, maintenance, and repair costs are all significantly higher than other conventional ventilation systems. A definite drawback is that a heat pump delivers the least amount of cooling or heating when the demand is the greatest. For example, when it is 20 degrees outside, the air coming through the vents will be much cooler than the air coming from a traditional furnace or boiler. And when it is extremely hot outside, the air coming through the vents will not be as cold as the air that comes from a separate air conditioning unit. The convenience of a heat pump may also be challenged by the fact that they can be rather noisy.
There are specific applications for a heat pump in which it would be much more practical than separate heating and cooling units. Be sure to factor all of the pros and cons for your particular climate. If you live in a climate that has extreme cold and warm temperatures, then a heat pump is probably not for you. If you live in a milder environment, such as the coast of California or in Hawaii, a heat pump may be more suitable.