Over the previous decade, warmth pumps have been steadily making their approach into extra American properties. There was a serious milestone final 12 months after they surpassed fuel furnaces in annual gross sales by a large margin.

However the blistering chilly climate descending on the Midwest this week has many householders questioning: Do warmth pumps nonetheless work in freezing temperatures?

Consultants and electrification advocates say that they do — and that even in chilly climate, they’ll nonetheless be extra environment friendly, and higher for the local weather, than furnaces and boilers that run on fossil fuels.

An electrical warmth pump is an all-in-one heating and cooling unit, primarily an air-conditioner that runs in two instructions. In the summertime, it features like a standard A.C. unit, pumping warmth out of the house and circulating cooled air inside. Within the winter, it attracts warmth into the house. Which may appear stunning, however it’s true. Even when it’s bitterly chilly exterior, there’s nonetheless warmth accessible. Because it will get colder, warmth pumps should work tougher, utilizing extra vitality, to extract that warmth.

However even in chilly climate, electrical warmth pumps are extra vitality environment friendly than the fuel or oil furnaces that warmth many properties. These furnaces generate warmth by burning gas. In concept, for each one unit of vitality enter, they’ll solely produce one unit of vitality output. In actuality, even probably the most environment friendly gas-powered furnaces don’t convert 100% of their gas into warmth. Some is all the time misplaced within the conversion course of.

Warmth pumps, in distinction, don’t generate warmth. They switch it. That permits them to attain greater than 300 % effectivity in some instances. As a result of they’re extra environment friendly, utilizing warmth pumps to chill and warmth properties will help householders lower your expenses on their utility payments, stated Sam Calisch, head of particular initiatives at Rewiring America, a nonprofit advocacy group.

In Maine, the place warmth pump adoption is rising, however the place a majority of properties nonetheless burn oil, householders can save hundreds of {dollars} in annual vitality prices by making the swap, in keeping with an evaluation from Effectivity Maine, an impartial administrator that runs the state’s energy-saving applications.

Many warmth pumps which are constructed for chilly climates do have hefty upfront worth tags. To melt the blow, a federal tax credit score from final 12 months’s local weather and tax legislation can cowl 30 % of the prices of buy and set up, as much as $2,000.

As they’ve grown in reputation, warmth pumps have more and more been the topic of false impression and, at occasions, misinformation. Fossil-fuel trade teams have been the origin of many exaggerated and deceptive claims, together with the assertion that they don’t work in areas with chilly climates and are more likely to fail in freezing climate.

Whereas warmth pumps do turn into much less environment friendly in subzero temperatures, many fashions nonetheless function near usually in temperatures right down to minus 13 levels Fahrenheit, or minus 24 Celsius. Among the newest fashions are much more environment friendly, and lots of “chilly” nations, like Norway, Sweden and Finland, are more and more embracing warmth pumps.

“We’re beginning to see proof that the parable has been stored alive by individuals with an entrenched curiosity in avoiding the adoption of warmth pumps,” Dr. Calisch stated.

There are further steps householders can take to benefit from their warmth pumps, like sealing air leaks and drafts and bettering insulation, stated Troy Moon, the sustainability director for town of Portland, Maine. Householders also can hold their current furnaces as backup for the coldest days of the 12 months, he stated.