While heat pumps in the US have traditionally been associated with warmer locations, they are starting to become more feasible for colder climes. “You can pretty much buy a heat pump for most climates in the US and it can lower your energy bills,” Allison Mahvi, a professor of mechanical engineering at the University of Wisconsin-Madison, tells Popular Science. Some of Mahvi’s research focuses on how to make more efficient heat pump systems for cold climates.