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Canary Media’s “Electrified Life” column shares real-world tales, tips, and insights to demystify what individuals can do to shift their homes and lives to clean electric power.
As Winter Storm Fern was dumping record amounts of snow and ice across the U.S. a couple of weeks ago, Kit Wu sprang into action.
Wu, the founder of the Boston-based heat-pump installation and research startup Laminar Collective, quickly reached out to his customers. He wanted to know how the more than 70 households his startup had installed heat pumps for were faring — and to address any performance issues that might have come up as the city weathered its eighth-biggest snowstorm in history.
The vast majority of heat pumps fared well, Wu’s customers reported. Even as Fern eventually departed and a brutal cold snap gripped the region, more than 90% of heat pump units held up without a hitch. But six did struggle.
Their owners saw dips in indoor temperatures and sent Wu photos of their outdoor units, the parts of heat pump systems that find warmth in even frigid winter air. These appliances had a significant buildup of ice on their backs — up to a half inch thick.
That wasn’t good.
Heat pumps, which provide both heating and cooling, use finned metal coils filled with refrigerant to extract thermal energy from the atmosphere. A stubborn crust of ice throttles airflow, making it tough for a heat pump to scrounge up enough heat to keep residents toasty, Wu explained.
For years, heat pumps have been popular in the warmer U.S. South, but not so much in chillier parts of the country. That’s changing. Tech improvements have made it possible for households in colder climes to embrace the appliances, which are always better for air quality and often cheaper to run than fossil-fueled boilers and furnaces. Even in notoriously frosty states like Maine, they’re taking off.
But with this new territory comes new challenges. While some heat pumps are designed to work in temperatures as low as minus 22 degrees, it’s possible for extreme, prolonged winter weather to dampen their efficiency.
That’s exactly what happened with the struggling heat pumps that Wu encountered: They had accumulated so much ice that they just “couldn’t keep up,” he said.
Thankfully, these challenges are surmountable. Wu was able to return each of the iced-over units to smooth working order in one visit. But it would have been better to avoid the issue in the first place. Here are a few steps you can take to help your heat pump perform at its best even on the worst winter days.
To keep your heat pump humming along in the freezing cold, bring in a heating, ventilation, and air-conditioning technician before the bad weather comes, said Mark Kasdorf, founder and CEO of Forge, a heat-pump installer based in Newton, Massachusetts.
“I think 99% of all issues can be taken care of by just having an expert take a look at the system,” he said.
A professional can perform what’s called a blower-door test to find any big air leaks in your home, which work against a heat pump. And have the technician check for blocked air filters — or do it yourself — particularly if you bought the home with the heat pump already installed.
“Tons of homeowners never change their filters,” Kasdorf noted, even though it’s something most can do on their own. Helpful YouTubers have demonstrated the process for both ductless and ducted systems.
You’ll want to give your heat pump space to breathe, with at least two feet of clearance. If snow or fallen leaves are common in your area, make sure your heat pump is raised off the ground. The appliance needs this space so that, when it goes into defrost mode, water can efficiently drain away, rather than refreeze into ice.
When snow is coming down hard, break out the shovel, Wu added. “If you’re going to dig out your car, you should also dig out your heat pump.”
You could even get a little awning or semi-enclosed hut for your system to give it extra protection from a storm.
A suffocated heat pump is a sad heat pump.
A layer of ice will cause it to run less efficiently and jack up your energy bills. But there are a couple of remedies you could try, Wu said.
One is to run the heat pump in reverse in cooling mode. That will heat up the coils, potentially allowing them to thaw their icy coats.
Another is a manual defrost: pouring room-temperature water over the ice. This trick worked on all the units that he recently tended to, Wu said.
Never use hot water, though, he noted; the metal could crack.
I’ll admit, I was a bit skeptical of this piece of advice. But Kasdorf insisted it has worked for him, so here goes.
If your appliance isn’t pumping out enough heat, then take a picture of the unit, upload it to an AI model — Gemini has worked best for Kasdorf — and describe the weather and your issue.
A large-language model can suggest quick fixes. When I gave Gemini a test case, it offered some of the strategies in this article, as well as warned me to resist the urge to chip at the ice with a sharp object. A misplaced stab could cause a refrigerant leak that takes the heat pump out of commission.
Treat the tool “like a really smart uncle” who’s an HVAC technician, Kasdorf said; the voluble advice may be helpful, if imperfect. It’s also best to think of this exchange as a starting point for some troubleshooting. If it provides anything that seems especially involved — or just weird — call a professional, he noted. And if your problems persist, the same applies: Work with your installer.
That is, after all, what Wu’s customers did, and the results speak for themselves.
Last Friday, 10 days after Fern swept through Boston, area temperatures were still well below freezing, and Wu could see snow piled high outside. But after the simple fixes he employed, every one of his customers’ heat-pump systems was working just fine.
Want more tips on keeping your heat pump humming even in extreme weather? Efficiency Maine has a plethora.
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