Every other Friday, the Outside/In podcast team answers one listener question about the natural world.
This week, Brian from Canaan, New Hampshire asks: “As a household gets ready to transition from one heat source to the next (to replace, for instance, an aging furnace) what’s the best method to make our carbon footprint smaller?"
To help us answer this question, we spoke to Nate Adams, who also goes by "Nate the House Whisperer." Nate says that, as far as emissions go, heat pumps are the best home heating system because heat pumps don't create heat like oil or gas-burning furnaces — they move heat from one place to another. And the amount of electricity used by heat pumps is significantly less than traditional electric heating options like electric baseboards and space heaters. So as the electrical grid continues to shift from fossil fuels to renewable energy, heat pumps — along with electric cars and induction stoves — have become part of the "electrify everything" strategy.
Heat pumps work by pulling heat from outside and moving it indoors. "Pulling heat out of the cold seems really counter-intuitive," Nate says when he explains how a heat pump works. Some of his clients are surprised, for example, to learn that heat pumps still work in sub-zero temperatures, down to -15 degrees F with some models.
"But the odds are you have one running in your house right now. It's called the refrigerator."
Nate says that refrigerators and air conditioners are technically heat pumps — they move heat from inside the refrigerator, or inside your home in the case of an air conditioner, to the outside. But while refrigerators and air conditioners only move heat in one direction, heat pumps can move heat in both directions, either into your home or out of your home, so they function as both heaters and air conditioning.
So heat pumps are more efficient, and help keep your home the right temperature year-round — but there are a couple important things to be aware of.
Emily Mottram, founder of Mottram Architecture in Maine, says, "they're not always installed correctly, and so we have an issue with refrigerant losses." Refrigerants are an even more potent greenhouse gas than carbon dioxide in their warming potential. Emily says to hire a qualified professional installer to ensure the equipment is properly installed so that refrigerants don't leak into the atmosphere.
Second, Emily says that before you even replace your heating system, you should get an energy audit to see if your home is weatherized or not. Joe Lajewski, energy solutions program administrator at the New Hampshire Electric Co-op, says that heating a home that’s not weatherized is like bailing water out of a boat that has holes in it.
"The better solution would be to plug up the holes first and then work on bailing the water," Joe says.
This means sealing cracks and penetrations, like wires or pipes that run through walls or floors. A tight home reduces the overall amount of energy needed to heat your home, and your system will run more efficiently.
So if your home needs a new heating system, experts say heat pumps are the way to go. But even if you weren't planning to replace that old furnace, there's good reason to consider making the switch.
At the end of the day, climate experts are telling us that we need to reach net-zero greenhouse gas emissions by 2050. Getting a heat pump, just like getting an electric vehicle, is part of the strategy to electrify everything and get off fossil fuels as soon as possible.
And caring about the climate isn’t the only reason to get a heat pump. They’re usually cheaper to run than any other heating system, and many heat pump owners think they’re just better: they’re quieter, they maintain a steadier temperature, and the air quality is better. That sounds like a win-win for home comfort, and the climate.
If you’d like to submit a question to the Outside/In team, you can record it as a voice memo on your smartphone and send it to outsidein@nhpr.org or call the hotline, 1-844-GO-OTTER.
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