The up-front costs of heat pumps remain high and will continue to be a barrier in many parts of the world, especially when it comes to more expensive models that pull heat from the ground instead of the air, or for homes that need to be retrofitted with new technology, Monschauer says.

Incentives like rebates and tax credits will be key in pushing heat pump adoption outside the narrow band of conditions where the appliances are already the most economical option, Monschauer says, in particular for lower-income households. Over 30 countries around the world have incentives in place, and new US programs could help even more homes use the devices to cut emissions and energy costs.

The Inflation Reduction Act, passed in the US last year, includes federal tax credits of up to $2,000 for taxpayers installing heat pumps. And rebate programs can include funding of up to $8,000 per household, depending on the state. 

How those incentives might change the distribution of heat pumps across the country remains to be seen. The fraction of homes that rely on them overall is still small, and there’s no guarantee that they will continue to be adopted at equal rates by households with different incomes. But researchers like Davis see the potential for incentives to continue bringing the cost savings and climate progress associated with heat pumps to everyone, not just the rich. 

“At least in the US, it has the potential to be really widely adopted, by a lot of different people,” he says. “There’s an egalitarian something about it.”