When it’s cold outside, most American homes burn gas or fuel for warmth ― a big part of why buildings are the country’s fourth-largest source of climate-changing emissions. When it’s hot, an even bigger percentage of households switch on electric air conditioners.
Heat pumps ― essentially two-way air conditioners ― can do both, warming homes without spewing fossil fuel pollution into the air. But buying and installing these machines generally costs more than air conditioners, government incentives to offset prices vary by state and many people simply haven’t heard of a heat pump.
A new bill set to be announced in the Senate this week aims make heat pumps more popular by boosting domestic production, giving manufacturers tax credits of between $600 and $1,000 per machine.
While far more limited than policies in some European countries, the proposed federal handout is meant to drive down prices in line with home cooling systems and spurring companies to market and sell more of the appliances in lieu of traditional air conditioners. If heat pumps become the standard cooling appliances in a country where 66% of households have central air conditioning, then why double up on heating by installing a fossil-fueled furnace or boiler, too?
“This legislation is a win-win ― reducing energy costs for consumers, while strengthening access to clean, energy-efficient heating solutions,” Sen. Amy Klobuchar (D-Minn.), the bill’s lead author, said in a statement.
Heat pumps transfer rather than generate heat. While an air conditioner absorbs heat from inside the building and moves it outside, a heat pump absorbs heat from outside and moves it inside. This works by circulating a refrigerant through an evaporator and condenser.
For every 1 kilowatt hour of electricity a heat pump uses, it produces 2 to 4 kilowatt hours of heat energy, making it up to four times more efficient than a regular boiler or furnace, according to Carbon Switch, a service that provides detailed guides on climate-friendly appliances. The Department of Energy found that heat pumps use roughly half as much power as traditional electric systems like space heaters or baseboard heaters.
“There’s very little difference from a hardware perspective between a one-way air conditioner and a two-way heat pump,” said Kevin Kircher, an assistant professor of mechanical engineering at Purdue University who researches heat pumps.
The bill, he said, is calibrated to make up the difference in hardware costs on the assembly line, making it cheaper to just manufacture two-way heat pumps instead of air conditioners.
“The big picture is that heat pumps today, in a lot of markets, are substantially more expensive than a gas furnace,” Kircher said. “This isn’t so much to make heat pumps cheaper than incumbent options but to make heat pumps more prevalent.”
But the efficiency of electric heating makes it less sensitive on average to price spikes from shocks in the fossil fuel markets even though most of the U.S. grid is still powered with gas and coal. A study last fall by the federal Energy Information Administration found that U.S. households heating primarily with natural gas would spend at least 30% more than the last winter’s average. Homes with oil heating were on track to spend at least 43% more. Propane users faced a 54% spike.
By contrast, households heating primarily with electricity were looking at a 6% cost increase last winter.
Once the U.S. generates the vast majority of its electricity from non-fossil sources, heating prices would be even steadier.
Heat pumps aren’t a perfect climate fix. While undoubtedly less damaging than burning gas or oil, the refrigerants used in heat pumps and air conditioners are potent greenhouse gases when leaked into their atmosphere. New international standards agreed to last month will set the stage for more climate-friendly chemicals, but the U.S. could be slow to adopt the cleanest coolants.
Some 12 million U.S. households already use heat pumps. The appliances are primarily deployed in the South, where nearly one-fifth of homes have heat pumps, and out West. Those regions tend to be hotter and saw the biggest increase in new housing construction over the past decade, making new technologies that provide both cooling and heat a more obvious choice.
Heat pumps have historically tended to be less efficient in extreme cold, when there’s just less warm air to pull from outside. But the technology has improved significantly over the past decade.
Colder states in the Northeast, which still relies heavily on oil for heating, are now seeing a double-digit rate of growth in heat pump adoption, compared to single-digit rises in the West, South and Midwest, according to a report from the Atlas Building Hub. State-level subsidies are helping. Massachusetts offers rebates of up to $10,000 off heat pump systems. New York’s rebates can top $7,500. Maine’s are up to $1,200.
“To really drive a transformation you need the carrot and the stick.”
Klobuchar’s bill marks a first step toward making heat pumps more of a national priority, said Parth Vaishnav, an assistant professor of sustainable systems at the University of Michigan, who called it “a start, a carrot.”
“But to really drive a transformation you need the carrot and the stick,” he said.
Since Berkeley, California, became the first U.S. city to prohibit new gas hookups, dozens have followed, with New York City becoming the largest to pass a ban last winter. No state has yet banned gas, though New York recently considered following its eponymous city. But nearly two dozen states, primarily led by Republicans, have passed laws barring cities from banning gas.
Europe offers a stark comparison. The Swiss city of Zurich voted to ban gas heating in November and eliminate the need for households to pick a single source by instead building a municipally-owned district heating system that would distribute warmth from a central location much like electricity is transmitted from a power plant. That model for heating is already popular in cold Nordic nations.
The United Kingdom is moving ahead with a ban on gas boilers, at least in England, and offering grants to households totaling nearly $6,300. Germany set a rule requiring all new heating systems installed after 2025 to run primarily on renewable energy. This month, the Netherlands ― once Europe’s top gas producer ― announced plans to ban new gas-only heating by 2026 and make heat pumps mandatory in most buildings.
Such mandates would be challenging to enact in the U.S., where an entrenched fossil fuel industry and a federalized system of government have made overhauling energy use difficult.
Building codes here are set at the state level but follow a generic set of measures drafted and updated every three years by the International Code Council, a nonprofit consortium of industry groups and state and city government officials. While governments have in recent years pushed for codes that mandate more electrification of new buildings, industry groups ― including trade associations of gas utilities ― have fought back. Last year, those groups succeeded in curbing the power governments have over what makes it into the final set of generic U.S. building codes.
Legislation outright banning gas or oil would also be unlikely to pass in the U.S. Senate, where most Republicans and a number of prominent Democrats remain staunchly opposed to policies that explicitly shut out fossil fuel businesses.
Klobuchar’s legislation has six Democrats signed on ― Sens. Tina Smith (D-Minn.), John Hickenlooper (D-Colo.), Sheldon Whitehouse (D-R.I.), Patrick Leahy (D-Vt.), Jeff Merkley (D-Ore.) and Cory Booker (D-N.J.). The bill includes provisions supporting organized labor, promising to increase applicable tax credits by 10% for heat pumps made in unionized factories.
If more conservative lawmakers like Sen. Joe Manchin (D-W.Va.) approved, the bill could be passed as part of a reconciliation bill, a Senate process that allows Democrats to use their narrow 50-vote majority to enact law.
But tax credits for companies producing clean-energy products have generally been popular with both Democrats and Republicans, meaning the legislation could ultimately pass through traditional means with some kind of bipartisan majority. The Senate voted 86-11 to pass a $40 million aid package to help Ukraine fight Russia with U.S. weapons.
As Europeans scrambling to replace Russian gas supplies, the U.S. is angling to sell the continent more liquefied natural gas. The new Senate bill proposes another option.
“To cut emissions, we need to green home heating. To squeeze Putin, we need Europeans to stop using Russian natural gas,” Hickenlooper said, referring to Russian President Vladimir Putin. “By spurring U.S. heat pump manufacturing we can lower emissions, cut European dependence on Russia and create jobs at home.”
CORRECTION: This story has been amended to account for an error in Klobuchar’s press release that attributed Hickenlooper’s quote to her.