Winter grid headroom could make heat pumps a ratepayer benefit

An RMI study finds about half of U.S. states have spare winter grid capacity, and more heat pumps could lower per-kWh rates, though not necessarily bills.

RMI, a clean energy think tank, has published a study arguing that heat pumps are less of a threat to the U.S. grid than often assumed. Canary Media reported it on 28 October 2026. In roughly half of U.S. states, RMI found, the grid has substantial spare capacity in winter to serve them.

The reasoning rests on timing. Across most of the country, demand peaks on hot summer afternoons because of air conditioning. Heat pumps would mostly replace less efficient air conditioners, so they would not raise that summer peak much. RMI looked at 24 states plus Washington, D.C., which it identified as having the most spare capacity. There, more heat pumps could lower rates for all customers by spreading fixed grid costs over more kilowatt-hours. Maximizing deployment without grid buildout could cut residential rates an average of 13% relative to what they would otherwise be, about $200 per customer per year. Michigan could install 3.6 million home heat pumps and cut rates by as much as 27%. Study co-author Ryan Shea compared the grid to an underused toll bridge whose fixed cost is spread across too few users.

For abundance, this takes away a common objection from utilities and policymakers: that electrifying heating would strain the grid. If it can instead push rates down, cheaper and cleaner home heating gets easier to justify. The study's optimal mix is 79% of households with hybrid setups, pairing a heat pump with existing fossil backup, and 21% all-electric. It says more hybrid heat pumps cut emissions more than fewer all-electric ones. In Illinois, the grid could handle only 30% of households relying solely on a heat pump.

The caveats matter. RMI calls its numbers directional estimates, not forecasts, and lacked utility-specific data. It did not estimate bill changes for households that switch. Parth Vaishnav of the University of Michigan called the work sensible and well done, but noted lower rates do not necessarily mean lower bills. A 2024 Michigan study he co-authored found switching from gas could raise some households' bills by more than $1,000 a year at then-current fuel prices. Savings depend on prior fuel, insulation, heat pump efficiency and fuel-to-electricity price ratios.

Source: Canary Media