Millions of U.S. homes have central air conditioning for the summer and separate fossil fuel heating systems for the winter. A great way to boost home heating electrification is to replace those central air conditioners with look-alike “two-way” heat pump units, which can provide highly efficient heating in addition to cooling, at little extra up-front cost. CLASP and RAP analyzed ways to make this happen in a recent report. Our recommendations included revising appliance standards to require ACs to have two-way operation.

Central AC vs. Heat Pumps

Earlier this month, the Environmental Protection Agency put this idea into policy, saying that two-way heat pumps deserve the agency’s coveted Energy Star “Most Efficient” rating — and that even the best traditional one-way air conditioners no longer do.

This is big news for building electrification. It means that the hybrid electrification idea — where households ease into electrification, retaining their old fossil systems only for backup on the coldest days — is gaining ground. This approach has the immediate benefit of cutting fossil-fuel use, as households use their legacy fossil systems less. It also helps to smooth the path to full home electrification by boosting demand for heat pumps, increasing the capacity of heat pump contractors and installers, and raising consumer familiarity with heat pumps.

The details of EPA’s move: The agency issued final recognition criteria for specific products to qualify in 2023 as Energy Star Most Efficient. In its response to stakeholders who encouraged the EPA to remove one-way central AC units from the Most Efficient program, the agency wrote that it “expects 2023 to be the last year we recognize central air conditioners” as qualifying for the rating. It went on to state that it “agrees that hybrid heating is the logical next step for retrofits in existing homes, given the modest incremental cost to install a heat pump instead of an AC.” Furthermore, it indicated that it is adjusting its “marketing and communication strategy accordingly.”

In encouraging the EPA to reach such a conclusion, stakeholders pointed out that traditional central AC units only provide cooling and are currently paired with a fossil-fuel-fired furnace that delivers 100% of a home’s heating needs. By contrast, switching from central AC to heat pumps would allow consumers to use a cleaner and more efficient appliance for at least some of their heating needs. That in turn would avoid approximately 250 million tons of CO2 over 10 years, save $27 billion on heating bills, and produce an additional $80 billion in societal benefits.

The hybrid heating strategy, as a way to kickstart home electrification in the United States, is described in detail in CLASP and RAP’s report: Combating High Fuel Prices with Hybrid Heating: The Case for Swapping Air Conditioners for Heat Pumps. We make the case for appliance standards requiring ACs to have two-way operation, and the EPA decision is an important step in that direction. We also provide analyses of four major heating fuel types — oil, propane, methane and electric resistance — and outline key recommendations for how state governments and utilities can support accelerated heat pump adoption across the country.

The Energy Star Most Efficient designation is intended for use at point-of-sale on materials and product literature. The goal of the program is to encourage new, more energy-efficient products into the market more quickly by targeting early adopters. With the EPA’s decision, consumers will now have better information about the most efficient choices to make for cooling appliances.

This change should also have significant effects on state- and utility-run efficiency programs across the country due to their reliance on Energy Star information to decide what appliances to support. Fifty-four million American homes have one-way central ACs that can be easily swapped for a two-way heat pump, which would run in a hybrid configuration to both cool and heat the home, with the existing heating system as colder-weather backup. In a world where fossil fuel prices are high and volatile, the electric grid is getting cleaner, heat pumps are getting more and more efficient, and the demand for air conditioning is increasing, a big push for a swap of air conditioners to heat pumps over the next five to 10 years will smooth the way for full building electrification.