The efficiency of any device is determined by output divided by input. To get above 100% efficiency more energy is being supplied than used. Geothermal heat pumps accomplish this. They are marvels of efficiency, supplying as much as 3-5 times the energy they consume. In general, they are 300-600% efficient. Compare this to a gas furnace at 98% efficiency or a condensing boiler at 95% efficiency. Because of their super high efficiencies, geothermal systems can save up to 70% on energy bills.
Geothermal systems are very reliable and durable: System life is around 25 years on average for the heat pump. The ground loop is considered a part of the building’s permanent infrastructure, similar to a home’s plumbing system. And because the loop is underground and the heat pump is located inside a home or building, unlike an air/conditioner compressor, the system is safe from corrosion and damage from extreme weather events.