If refrigerant, the key substance inside a heat pump leaks into the atmosphere, it can warm the planet thousands of times more than CO2. The Possibly team does the math to see if that risk outweighs the climate benefit of heat pumps.
Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.
Heat pumps are a nice option for heating and cooling your house. They run on electricity, and they’re more efficient than other options. But, heat pumps also use a substance that’s not so climate friendly. Is it still worth buying them?
Leo Nachamie and Christine Peng from our Possibly Team are here to explain.
Leo Nachamie: Hey Megan!
Christine Peng: Hi!
Megan Hall: Okay, so we keep hearing a lot about heat pumps, but I don’t have them. Why should I care?
Leo Nachamie: Heat pump technology is actually way more common than you might think. Everyone already has something kind of like a heat pump in their home. It’s your refrigerator.
Christine Peng: And it’s the same technology in air conditioners, too. You can even use heat pumps to heat water!
Megan Hall: Wow, they really are everywhere. So how do they make heat?
Christine Peng: Well, they actually don’t make heat at all! Instead, they just move heat from one place to another, kind of like how a water pump moves water from one place to another.
Leo Nachamie: So in the case of a refrigerator, it’s moving heat from inside the fridge to the outside, and that’s how it stays cold.
Christine Peng: And since heat pumps just move heat around instead of generating it, they use less energy than other options like burning gas or oil.
Megan Hall: Okay, heat pumps seem like a really sustainable choice for heating and cooling your home. What’s the hang up?
Leo Nachamie: Well, to work, heat pumps need both electricity and something else— a refrigerant, which can cause some problems.
Megan Hall: What is a refrigerant exactly?
Leo Nachamie: Basically, it’s just a substance that’s good at absorbing heat, moving it, and then releasing it somewhere else.
Christine Peng: Which is what makes refrigerants so great for the way heat pumps work.
Megan Hall: So, what’s wrong with refrigerants?
Christine Peng: Well, nothing is air tight. Over time, refrigerants can leak out and end up in the atmosphere.
Leo Nachamie: And the refrigerants used in today’s heat pumps trap a lot of heat in our atmosphere. One molecule of refrigerant might trap somewhere between one thousand or two thousand times as much heat as one molecule of CO2.
Christine Peng: So even a little leak can be a big deal, and if more people switch to heat pumps, all those little leaks could add up quick.
Megan Hall: Yikes! Can you put this into perspective for me? If I had heat pumps, what would happen if all of the refrigerant leaks at once? Like, if the canister breaks or something?
Leo Nachamie: This actually happened to our show’s founder, and Brown University’s provost for sustainability, Stephen Porder.
Christine Peng: The tubing that held the refrigerant for his new heat pump water heater was cracked when it arrived.
Stephen Porder: This was a major, major trauma in my house.
Leo Nachamie: For everybody involved.
Stephen Porder: My daughter actually, like age seven, or whenever it happened, she drew a very complicated hot water heater diagram that encapsulated her understanding of the giant problem. It wasn’t really a giant problem, but I was very upset about it for a minute.
Christine Peng: And for good reason, because that’s a lot of emissions.
Stephen Porder: It was probably about a year, or maybe even two years, before the energy savings that I had from running that hot water heater would make up for the emissions of that little cracked tube.
Leo Nachamie: So, in the end, his water heater prevented more emissions than the leak created, but it took a while.
Megan Hall: So, even in the worst case scenario— when all of the refrigerant leaks out of your heat pumps— they still create less greenhouse gas than other heating and cooling options?
Christine Peng: Yes, heat pumps generally last between ten to fifteen years, so that’s plenty of time to cancel out the effects of your refrigerant getting into the atmosphere.
Leo Nachamie: And, there are new refrigerants coming onto the market that don’t trap as much heat if they leak.
Megan Hall: So what’s the bottom line?
Christine Peng: If you’re thinking about switching to a heat pump, go for it! It’s a climate win and can cost less than other heating options.
Leo Nachamie: And, if you really want to nerd out, look for heat pumps with “low global warming potential refrigerants.” These are the new ones that are better for the environment.
Megan Hall: Great! Thanks, Leo and Christine!
That’s it for today. You can find more information, or ask a question about the way your choices affect our planet, at askpossibly.org. You can also subscribe to Possibly wherever you get your podcasts or follow us on Instagram, Facebook, LinkedIn, X, or Bluesky at “askpossibly”
Possibly is a co-production of Brown University’s Institute for Environment and Society, Brown’s Climate Solutions Initiative, and the Public’s Radio.
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