A new report from the energy thinktank RMI challenges the idea that a mass switch to electric heat pumps would overwhelm the US power grid. The analysis finds that because winter electricity demand is generally far lower than summer demand, there is enough spare capacity — or “headroom” — to power heat pumps in roughly 109 million homes, or about three-quarters of all US households.
Heat pumps move heat from outside air into a building rather than generating it by burning fuel, and modern cold-climate models already work well in freezing temperatures. The RMI report focuses on the next concern: whether adding millions of electric heating systems would force costly grid expansion. Instead, it argues that winter heating load could fill existing idle capacity, spreading fixed grid costs over more electricity sales and potentially lowering rates for everyone.
The report notes that the picture varies by region. Hotter places with mild winters have different demand patterns, and utilities that rely heavily on solar see less winter generation. Still, the authors point to batteries, vehicle-to-grid experiments, and long-duration storage as ways to keep the grid flexible. Ryan Shea, a manager on RMI’s buildings team, said the country would be “better utilizing the grid capacity that’s already there,” with benefits for both climate and consumer bills.