Heat Pumps & Mini-Splits
Another common whole-house system for moderate and warm climates is the air-source electric heat pump. Primarily driven by the need for air conditioning, a heat pump uses a refrigerant to cool the house during warm weather. When it’s cold out, the pump can reverse the cycle to heat the house. Surprisingly, heat pumps can be more energy-efficient than other types of electric heat, including gas furnaces.
A more recent type of heat pump, called a ductless or “mini-split,” is an ideal retrofit option for homes with no existing duct system. Multiple wall-mounted indoor units can be installed in individual rooms, all connected to a single outdoor unit. Like any heat pump, this type can provide both heating and air conditioning, but without the expense and destruction of installing a duct system. Many if not all ductless systems are Energy Star certified and can cut heating and cooling costs by up to 30 percent.
Geothermal systems (see Know-How, p. 60) powered by heat pumps are even more efficient, because they absorb heat from either the ground or from water pumped from below ground.
LEFT In a mini-split system like this one from Rheem, the heat pump (at back) is installed outdoors, powering one or more of the indoor units (at front).