An open loop system does not actually “use” any water since it does not consume the water and the water returns to the environment. Combustion appliances that “use” gas or oil actually consume the fuel, never to be available again.
Geothermal heat pumps used in open-loop systems need differing amounts of water depending on the size of the unit and the manufacturer’s specifications. The water requirement of a specific model is usually expressed in gallons per minute (g.p.m.) and is listed in the specifications for that unit. Your water well and heat pump combination should be large enough to supply the water needed by the heat pump in addition to your domestic water requirements.
Posted in: Geothermal FAQs