Heat pumps are increasing in popularity for homes, especially homes that don’t have connection to a natural gas line. Using a heat pump consumes much less energy than an electric furnace, making one an ideal choice for an all-electric household.
If you are spending your first winter with a heat pump to warm your home and family, there are a few things you’ll need to acquaint yourself with. Heat pumps can do things during cold weather that will look suspicious to people who aren’t used to them. They might make it look like the heat pump needs repairs. But these are normal activities, as we’ll explain.
The Outdoor Unit Runs When the Weather Is Cold
Since a heat pump works much like an air conditioner (basically, it’s an air conditioner that can change the direction it works so that it’s also a heater), people take their expectations for how ACs work over to heat pumps. They don’t expect the outdoor unit of an AC to run during cold weather!
But this is just how heat pumps run: during the cold weather, the indoor and outdoor coil swap jobs, so the outdoor coil draws heat from the outdoor air to transport indoors. It would be a serious problem if the outside unit of the heat pump wasn’t running.
There’s Smoke Coming from the Outdoor Unit
Nobody wants to see smoke rising off a mechanical appliance, and the sight of it coming from the outdoor cabinet of the heat pump can definitely be alarming. But what you’re seeing isn’t smoke at all but water vapor from the defrost cycle. Ice forms along the outdoor coil as the heat pump runs because the moisture along it freezes in cold weather. Because the coil cannot function as a thermal absorber with ice on it, the heat pump periodically switches to a defrost cycle to heat the coils and melt the ice. This is the source of the “smoke”: water vapor from the melting ice.