The promise of water-source heat pumps

About half to two-thirds of the average Western Washington home’s energy use is for space heating and cooling, and water heating. Normally, temperature management is either accomplished by burning gas or propane, or by using an electric resistance heater or air-source heat pump.

There’s another, more energy-efficient option: Water-source heat pumps. These systems operate on the same basic principles as other heat pumps. They transfer heat from one side of the system to the other. In an air-source heat pump (an air conditioner with a valve that allows it to operate in both directions instead of...