In this episode of the Ask Derrick Cole Show, Derek Cole and co‑hosts address homeowner concerns that arose after a recent ice storm. The main questions focus on whether a heat pump can still extract heat when outdoor temperatures drop below freezing, when (or if) to switch to emergency (electric) heat, and what to do when the outdoor unit appears frozen. Cole explains that modern heat pumps continue to pull heat from the air down to about 30 °F, using supplemental electric heat as needed, and that turning the heat pump off in favor of electric heat is a mistake. He describes the defrost cycle—how frost builds on the outdoor coil, triggers a melt cycle that produces visible steam, and then resumes normal heating. The advice is to keep the heat pump running, maintain the indoor thermostat setting, and allow the defrost process to work, while also ensuring the unit is clear of surrounding ice so it can “breathe.” The episode provides practical, safety‑first guidance for homeowners dealing with frozen outdoor units after power outages.
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Hey, on this episode we're talking about will my heat pump still work in freezing temperatures, and once my power comes back on, my unit is frozen. You ask your comfort and energy questions and they get answered. This is the Ask Derrick Cole Show.
Hey, this is Derrick Cole.
Welcome to episode 67 of the Ask Derrick Cole Show, answering your home energy and heating and air questions. And after the ice storm last weekend, we had quite a few questions and we'll get into it right now.
Should I turn my heat pump to emergency heat when it drops below freezing?
The heat pump is— this is kind of some misinformation out there. The heat pump can actually pull heat out of the air as long as there's heat is in there. So if it's 32, 31, 30 degrees outside, the heat pump will still be able to work. Now, it will bring on the electric heat, backup heat, emergency heat to help it achieve what temperature you want in the house, but it does not stop from working. So when it gets 32 or 30 outside, to turn your heat pump off and turn to electric heat would be a mistake. I would not do that because it could still extract the heat from the air and bring it into the home.
Now, The electric heat will be running more often because chances are inside the house you have it 68, 70 degrees, whatever it is.
So it will need that backup heat to help it achieve that temperature.
But it's still going to operate the heat pump.
So leave the heat pump on.
And yes, your emergency heat backup heat will be working to achieve that indoor temperature. And what will also happen is with those kind of temperatures, it'll defrost more. So if you look outside of your unit, you might see steam coming out of it. That's because it's defrosting. It's on the defrost cycle. As it pulls the hot air out of the cold air, it does freeze up that coil or frost up the coil. So it goes into a defrost cycle, which melts that frost off. Steam comes up because of the temperature, and that's normal operation. You're good to go. So yeah. Leave the heat pump on and leave your temperature set. There's nothing special you need to do.
"My unit is frozen after the ice storm.
What can I do to get it working again?" Yeah, this was a big problem here locally anyway because we had some power outage. So when people got back, you know, the power 24, 36 hours later, of course After the freezing rain and a little bit of snow, the unit was iced over. So the best way to tackle that is to melt that ice on the outdoor unit yourself. Well, first of all, at the thermostat inside, I would turn it to emergency heat, right? Turn to emergency heat, get off the heat pump, because now the ice and the snow is around that unit. It cannot get the air from the outside. So don't do any damage to it. Turn on emergency heat. And then I just thought, because the next day it gets pretty warm, or warms up pretty good— I mean, today is like 55, 57 degrees outside— so simple garden hose, a little bit of water, room temperature, you melt the ice off, get off the unit, and then let it resume normal cycle once it can breathe. What's happening is it can't breathe because the ice and the snow is all around the unit. It cannot extract any heat from the outside air. Therefore, it's probably blowing cold air in the house. So turn it to emergency heat, melt that ice off, and you should be good to go from there.
