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Today, heat pumps are gaining popularity as the most cost-effective and scalable solution for heating homes and other buildings. Some question the impact of the refrigerants they use on the climate and even suggest postponing the purchase of a heat pump. Fear not, while modern refrigerants do have an impact on the climate when they are released into the air, the net climate benefits of heat pump heaters and water heaters are evident even today and getting better every year. The reasons are as follows:
A heat pump transfers heat from the air or the ground to the inside of your home or to a hot water tank. They require only a small amount of electricity compared to traditional electrical equipment, so their efficiency ranges from 300% to 500%. The electricity used to run heat pumps isn’t quite clean yet, but it’s fast getting cleaner as solar and wind are cheaper than fossil fuel electricity, and grid decarbonization will be accelerated by the recently passed Inflation Reduction Act.
Air conditioners (AC) and heat pumps use hydrofluorocarbons (HFCs) as refrigerants or heat transfer fluids. When HFCs leak from equipment, they are strong endothermic pollutants. The NRDC and its allies have been working for a long time to replace HFCs with safer and climate-friendly alternatives, and we are getting results: in December 2020, Congress passed the bipartisan AIM Act, which will replace HFCs over the next 15 years, production has decreased by 85%. Compliant with the Kigali Amendment, a global agreement to phase out HFCs worldwide. The EPA’s next step is to issue new regulations to eliminate the use of HFCs in new products for which alternatives already exist, as well as to contain spills and recover HFCs for reuse from existing equipment. Major states such as California implement their own additional rules.
What about the refrigerants used in heat pumps today? Should you wait and let those fossil fuel stoves and water heaters burn longer, or switch to a heat pump now? In fact, in almost all cases, the climate benefits of phasing out natural gas and reducing electricity use far outweigh the impact of current refrigerants, so the delay will cause more, not less, climate damage. The refrigerant is harmless as long as it does not leak. Measures to reduce leakage through good installation and maintenance are discussed below.
Most modern heat pumps use R-410A refrigerant, which has a global warming potential (GWP) of 4260 over 20 years. This means that when a pound of refrigerant enters the atmosphere, it absorbs 4,260 times more climate shock than a pound of carbon dioxide. Alternative refrigerants account for less than a quarter to one percent of the climate impact of R410A and other high-GWP refrigerants. That is why we are gradually reducing them.
But while HFCs are bad for the climate, carbon dioxide and methane emissions from conventional electrical and gas appliances are far worse. This is because the GWP itself is not the most important – the amount of gas emitted multiplied by its GWP determines the climate hazard, and the production and transmission of electricity and natural gas emits many more pollutants than HFCs. UC Davis researchers demonstrate this in the study we summarize: The Climate Mathematics of Home Heating Electrification. Taking into account all emissions from heating, including power plants feeding heat pumps and stove blowers, refrigerant leaks, carbon dioxide and methane emissions from gas stoves, modern heat pumps reduce emissions by 45-70% compared to gas stoves. The study was conducted before the adoption of the Inflation Reduction Law and did not take into account its impact on accelerating the decarbonization of the network.
We need to cut all of our warming emissions: carbon dioxide from burning fossil fuels, methane from gas system leaks, and refrigerant leaks from equipment. Today, heat pumps can perform all three functions.
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