California ‘Likely’ to Limit GWP for Heat Pump Water Heaters

Future regulations in California will “likely” include new GWP limits on heat pumps for heating potable water, pools and spas, and for clothes dryers. In addition, the upcoming 750 GWP cap on heat pumps used for space heating (and air conditioning) will probably not be “tenable” in the future and would be subject to being lowered.

The reason for these possible moves? California’s plans to decarbonize its building stock by removing natural gas and propane, and switching to electricity only (eventually supplied by renewable energy sources).  Electrifying buildings will mean an increased need for heat pumps. These units, including current space heating equipment, are still mainly based on f-gases, and so business-as-usual would lead to increased HFC emissions from this sector.

Those messages were shared by Glenn Gallagher, Air Pollution Specialist at the California Air Resources Board (CARB), speaking during the ATMOsphere America conference, held online on November 3. ATMOsphere America was organized by ATMOsphere (formerly shecco), the publisher of this website.

As California moves toward electrification, all new appliance sales “should be fossil-fuel free” by 2030, said Gallagher. In regard to water heaters, for example, “all-electric resistance heating is not very efficient, so we think heat pumps will be the way to go,” Gallagher said, adding that “we would like these heat pumps to use a very low GWP heat transfer fluid.”

In answer to a question from the ATMOsphere America audience, Gallagher said California’s electrification program could make it “the heat pump capital of the world.”

In 2019, heat pumps used for water heating, clothes dryers and pools/spas represented 1% of HFC emissions, but that would increase to 7% in 2030 under current regulations, Gallager said. HFC emissions from space heating/air conditioning would grow from 28% to 37%.

“We are very concerned about other types of heat pumps,” Gallagher said, adding that these heat pumps and ACs will most likely “be the main challenge” when it comes to finding the additional HFC emissions reductions needed to achieve California’s climate goals.

California is also concerned about capturing and recycling the HFCs used in the installed base of HVAC&R equipment, and may enhance regulations for that segment.

At the moment, HFCs only account for about 5% of California’s total GHG emissions, but they are a “stubborn” 5%, and this figure will increase as other sources are decreasing, meaning that “even with the reductions we have on the books today, we will need additional reductions,” Gallagher said.

New regs not enough

Last year, California approved bans on refrigerants with a GWP of more than 150 for new refrigeration with more than 50lbs of refrigerant, and on refrigerants with GWPs of more than 750 for AC. The 150-refrigeration ban will come into effect in 2022; the 750 limit for AC/space heating will be phased in between 2023 and 2026. However, these limits could be lowered further in time, Gallagher explained.

“Is the [750 GWP cap] tenable going forward? Probably not,” Gallagher said. Moreover, future regulations “will likely include new GWP limits on heat pumps used for anything other than space conditioning,” he said.

He cautioned that these “are not promises set in stone.”

But because California wants heat pumps to use extremely low GWP refrigerants, that would “very likely” include CO₂ (R744) and hydrocarbons, Gallagher said. Currently, CO₂ heat pump water heaters for domestic and commercial installations are available in the U.S. from ECO2 Systems, and for commercial installations from Mitsubishi and Lync.

Due to regulations, propane (R290) heat pumps are not known to be used currently in the U.S., but an R290 heat pump water heater for domestic use is available from Chinese manufacturer PHNIX, while a heat pump/AC for space conditioning is produced by German manufacturer Viessmann for large residential buildings, neighborhoods, commerce and industry.

Gallagher stressed that California tries to be technology “neutral,” meaning both natural refrigerants and HFOs are acceptable in the current plans. “We are taking a wait-and-see approach to HFOs; they are allowed by all federal laws, and California is not going to go forward and be completely different on this one – unless it is proven to us that HFOs will be environmentally unacceptable,” he said. Researchers and others have lately been warning of potential future harm from HFO-1234yf.

California works with both stick-and-carrot-type actions. The stick includes the GWP limits being introduced and regulations stipulating enhanced recovery, reclaim and reuse of refrigerants. Carrots include incentives, but money for this kind of motivation is not easy to come by, Gallagher explained. This is why CARB is hoping to join forces with some of California’s electricity utilities, which have deep pockets and something called the public goods fund, to incentivize installing only low-GWP equipment, including for refurbishments.

California has an executive order that the state will be carbon neutral, or net-zero, by 2045. However, the state has been thinking of lowering that deadline to 2035. “Because climate change is real, and we have terrible problems in California with fires and droughts,” said Gallagher.

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