There are several types of heat pumps that are appropriate choices in our area: Ducted air source heat pumps: Ducted split heat pumps have been a common choice for homeowners in relatively mild climates for decades. Traditionally they have required back-up or supplemental heat when the outdoor temperature drops to near or below freezing. Modern split heat pumps are now much more efficient and can operate efficiently well below freezing, but in colder climates will likely still need supplemental heat from electric resistance elements, or from a gas furnace as part of a dual fuel system. Ductless mini split heat pumps: If your home does not have an existing duct system, or you are adding a conditioned space that cannot be served by your existing HVAC system, a ductless mini split heat pump is an excellent choice. An outdoor unit is combined with one, or as many as 8 indoor units, each with its own zone controls. Mini split indoor units come in a variety of configurations and typically do not require ductwork. In very cold climates, there are ductless mini split heat pump systems that offer rate capacity and efficiency well below 0°F and may not require any supplemental or back-up heating system. Water source or ground source heat pumps: Also known as geothermal heat pumps, (GHPs) this class of heat pumps use the constant temperature of the earth as the exchange medium instead of outside air. Throughout our area, while outdoor air temperatures vary from very cold to extremely warm, ground temperature below a few feet remains virtually constant. Because of this constant temperature, GHPs are extremely efficient and do not require backup or supplemental heat on cold days. While GHPs are relatively costly to install they often offer the lowest ongoing operating cost.