Deploying residential heat pumps more widely across the United States has the potential to help reduce carbon pollution while also saving homeowners money, according to a new study by a University of Michigan researcher and colleagues.
However, in most parts of the country the electricity grid will have to get cleaner and electric heat pumps will have to get cheaper before these devices become both environmentally and financially compelling, says Parth Vaishnav of the Center for Sustainable Systems at U-M’s School for Environment and Sustainability.
The study was published online July 28 in the journal Environmental Research Letters. The other authors are Thomas Deetjen of the University of Texas and Liam Walsh of Carnegie Mellon University.
What is a residential heat pump? I’ve seen them described as essentially an air conditioner that is slightly modified so that it can run in two directions, cooling the home in the summer and providing heat in the winter. Is that correct?
That’s exactly right. Heat naturally flows from hot places to cold places, just as a car will roll downhill. During the summer, air conditioners move heat from a cold place (the inside of your home) to a hot place (the outside). During the winter, air conditioners can operate as a heat pump and do the same thing, except that the cold place is the outside and the hot place is your home. Just as you need to do some work to push a car uphill, you need to do some work to push heat from a cold to a hot place. What makes heat pumps efficient is that you usually can transfer two or more units of heat for every unit of work.
