Yes. If you have an open-loop system, your entering water temperatures (EWTs) may range from the 70s in the southern United States to the 40s in Canada. All heat pumps can handle temperatures in the moderate to warm ranges. A closed-loop system, on the other hand, will encounter EWTs below freezing. Not all geothermal heat pumps will operate efficiently at those temperatures. It’s important for you to know what EWTs your heat pump will handle.