We are all familiar with electric air to air heat pumps which provide forced air heating and cooling…sometimes referred to as mini splits. These air-to-air heat pumps have been used for whole house and spot cooling and heating combined with an electric heat pump water heater providing the domestic hot water.
There is also very efficient air to water and geothermal heat pumps (Hydronic Heat Pumps) that generate hot and chilled water for hydronic systems plus more efficient domestic hot water supply. All these types of heat pumps can cut electric heating, hot water and cooling energy very significantly opening the door for being powered by reasonably sized solar systems or as cost-effective alternatives to propane and oil fueled systems.
In the past few years, with the development of inverter technology, air to water heat pumps can provide warm water at low ambient air temperatures, boosting their geographical range and popularity. Combined hydronic heat pump systems offer the comfort of radiant heat and more economical hot water generation than a stand-alone heat pump water heater.
Geothermal heat pumps can make sense in applications where land is available for a ground loop and rebate programs exist.
Hydronic heat pumps are central to any hydronic heating Net Zero Energy strategy as solar electricity can power these systems.
Additionally, as a high efficiency boiler may be 95% efficient, a modern hydronic heat pump can be 350-600% efficient due the magic of refrigerant changes of state and modern compressors. That means that the use of an electric hydronic heat pump can be, and often is, more cost effective than gas or oil.