Matt Simon is a senior staff writer covering biology, robotics, and the environment. He’s the author, most recently, of A Poison Like No Other: How Microplastics Corrupted Our Planet and Our Bodies.
Photograph: Leon Neal/Getty Images
Our descendants will look back on this time in human history with a mixture of confusion and disgust. Americans spend around 90 percent of their time in indoor spaces, which we heat by burning fossil fuels that also warm the planet and sully the air of our homes. Our descendants will be especially confused because for years we’ve had easy access to a cleaner, more efficient alternative: the fully electric heat pump.
At long last, though, the humble heat pump is exploding in popularity. Unlike a boiler or furnace, which burn fossil fuels to produce heat, this device transfers heat through an outdoor unit into the indoor space. (It looks a bit like a traditional air conditioner.) In the winter, a heat pump extracts heat from outdoor air, but it can be reversed in the summer to pump heat out, providing cooling. Exchanging heat in this way is much more efficient than generating it.
In 2021 4 million heat pumps were installed in the US, up from 1.7 million in 2012. Europe, too, is coming around to the heat pump, with sales increasing 28 percent in Germany in 2021 and 60 percent in Poland. That’s no small feat, given the global pandemic slowdown, and it’s just the beginning of growth, especially with Europe’s push for energy independence from Russia amid the war in Ukraine.
“Heat pumps are a few years behind electric vehicles but really deserve similar attention and could deliver very sizable reductions in emissions if we deployed them much more rapidly,” says Jan Rosenow, director of European programs at the Regulatory Assistance Project, an NGO dedicated to the transition to clean energy.
Here’s how heat pumps work, how governments can use them to reduce emissions, and how you can get your hands on one.
Moving Heat, Not Making It
A heat pump works on the same principle as a refrigerator, which keeps your food cold not by pumping cool air in, but by pumping warm air out. The heat you feel on the outside of the machine is actually being transferred away. Similarly, a heat pump can cool a building by moving hot air out. Or, in the winter, a heat pump can warm a building by operating as a sort of “reverse refrigerator,” extracting heat from even cold outdoor air and bringing it inside. (That’s putting it simply—the engineering involved is rather complex.)
“The air may be relatively cold, but it’s transferring heat from that cold air into your home,” says Randal Newton, vice president of engineering of Trane Technologies, which makes heat pumps. “Your refrigerator is cold, and it’s still transferring heat into your kitchen from that cold box.”
Home heat pumps can even run on the geothermal energy in your backyard. Instead of exchanging heat with the air, a geothermal pump uses plastic pipes buried in the yard to exchange heat with the land itself. (You don’t have to live on top of a hot spring; once you get four or five feet deep in the ground, it stays at a fairly constant temperature year-round.)
“The easiest way to think about this is like your backyard is a battery,” says Ryan Dougherty, president of the Geothermal Exchange Organization, a trade association that advocates for geothermal heat pumps. “You can draw off that thermal battery in the winter and you can heat your house with the energy that’s right there in your yard. And then in the summer, the processes is just reversed: You take heat out of your house and you put it back into the battery.”
The downside of a heat pump is that you can’t install one on your own, unless you’re really handy. Whether it uses air or geothermal energy, a heat pump is no more difficult to install than an air conditioner, but you still need a professional. But the upside is that heating and air conditioning companies (disclosure: my aunt owns one such company) have been installing these things for years, so it’s just a matter of getting in touch with local businesses for quotes.
Cooling the Planet by Warming Your Home
Installation is going to run you between $4,000 and $8,000, but a heat pump pays dividends with its efficiency: It uses half the electricity of electric furnaces and baseboard heaters. “Even if your heat pumps are powered on coal power, it’s still a big upgrade,” says Duncan Gibb, lead analyst for heating and buildings at REN21, which advocates for renewables. “There’s really nothing to lose by making buildings more efficient as quickly as possible and deploying heat pumps. I think that the government should really be taking this seriously now.”
The long-term idea, of course, is to run heat pumps on power generated with renewables, not fossil fuels. But the economics are a bit tricky. Buying a heat pump is an upfront expense, and fossil fuels like gas for furnaces remain cheap. But as heat pumps grow in popularity, prices will come down, as happened with solar panels. So it’ll get cheaper to heat and cool a home cleanly, says New York University climate economist Gernot Wagner, who thinks of both of these technologies as investments. “It’s like the solar panel,” he says of heat pumps. “First you spend a lot of money, right? Much less of course now than ever, but you spend the money and once you have it, you’re printing free electricity.”
To make heat pumps more affordable, especially for low-income folks, governments need to offer tax breaks and hefty subsidies to incentivize homeowners and building owners to switch. (Honestly, if billionaires really cared about saving the planet, they’d pay for everyone to get heat pumps.) But officials can also ban new gas hookups, as cities like New York City and Berkeley are already doing. “Let’s cut the gas line, let’s put in a heat pump,” says Wagner. “It makes for a better indoor climate, it makes for a better home. It’s a no-brainer.”
Another option is “heat as a service,” in which a homeowner would pay a monthly fee for a company to install and maintain a heat pump. (Such programs are starting to pop up across Europe.) “It’s sort of like a phone plan,” says Gibb. “This is obviously great because it takes not only the upfront cost away from the consumer, but also it reduces their risk that’s associated with price fluctuations in fuel.” So if your local power plant is still running on fossil fuels, and the price of those spikes, you don’t take a hit on your heating bill.
One of the next challenges will be manufacturing more heat pumps. Another will be finding the labor required to install them. Gibb says the United Kingdom has a plan to install 600,000 heat pumps by the year 2028, which would require way more installers than are currently trained to do the work. “There’s a lack of skilled installers across the board,” says Gibb. “There’s a lot of smaller companies out there that do gas boiler installs, and do retrofits and things like that, but they’re not necessarily equipped to know how to install a heat pump.”
So an accelerated deployment of heat pumps will require juicing manufacturing—the Biden administration reportedly considered invoking the Defense Production Act to churn out the appliances to help Europe wean off Russian fossil fuels—as well as a massive training program for skilled workers to install the things. Our descendants, and the planet, will certainly appreciate the effort.