An air source heat pump (ASHP) works by transferring heat absorbed from outside air to an indoor space. It works through wet central heating systems to heat radiators and provides domestic hot water. An air source heat pump can provide efficient heating and cooling for your home. When properly installed, an air source heat pump can deliver up to three times more heat energy to a home than the electrical energy it consumes.
This is possible because a heat pump transfers heat instead of converting it from a fuel such as combustion heating systems. Compared to a fuel-fired combustion furnace or a standard heat pump, this type of system can also be more economical. Absorption heat pumps use heat or thermal energy as an energy source and can work with a wide variety of heat sources, such as combustion of natural gas, steam, solar heated water, air or geothermally heated water and are therefore different from compression heat pumps that operate with mechanical energy. Although most heat pumps use electric resistance heaters as a backup for cold weather, heat pumps can also be equipped in combination with a gas furnace, sometimes referred to as a dual-fuel or hybrid system, to supplement the heat pump.
Many air source heat pumps are primarily designed as air conditioning units, mainly for use in summer temperatures. The advantage of a ground source heat pump is that it has access to the thermal storage capacity of the ground, which allows it to produce more heat for less electricity in cold conditions. As wind farms are increasingly used to supply electricity to the grid, the increase in winter load coincides well with the increase in winter generation from wind turbines, and quieter days reduce the heating load in most houses, even if the air temperature is low. ENERGY STAR certified air conditioning and central air conditioning source heat pumps can be found in the CEE-AHRI database.
Heating and cooling is achieved by pumping a coolant through the inside and outside coils of the heat pump. Air source heat pumps have been used for many years in almost all parts of the United States, except in areas that experienced prolonged periods of freezing temperatures. Air-to-water heat pumps use radiators or underfloor heating to heat or cool an entire house and are often used to provide domestic hot water as well. There are few heat pump manufacturers that incorporate both types of heat into one box, so these configurations are usually two smaller standard systems, side by side, sharing the same ductwork.
There should be 400 to 500 cubic feet per minute (cfm) airflow for each ton of heat pump air conditioning capacity. Designing a heat pump specifically for heat exchange can achieve a higher COP and a longer life cycle. A high efficiency heat pump can provide up to four times more heat than an electric resistance heater with the same amount of electricity. Air source heat pumps are used to provide indoor space heating and cooling even in colder climates, and can be used efficiently to heat water in milder climates.