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Odd Heat Pump Behavior That Actually Isn’t Odd

You probably have spent the majority of your life in homes that received their winter heat from a furnace. If this is your first winter using a heat pump for comfort—either because you had it installed in spring/summer or you’ve moved into a house with a heat pump already in place—you might find it does a few surprising things as it switches into heating mode.

Here are two specific things it will do that may seem like malfunctions. They aren’t, however.

1) The Outdoor Unit Is Running when It’s Cold

You’ve had the heat pump running during the summer in cooling mode, when it acts identical to a standard air conditioner. Since you aren’t used to an air conditioner’s outdoor cabinet operating during the winter (you only use the indoor blower fan to work with the heater), hearing it running for a heat pump during the cold months might simply sound wrong.

However, this is the standard way a heat pump does its job when in heating mode. A heat pump is essentially an air conditioner that can reverse the direction it moves heat. The outdoor unit is absorbing thermal energy from the air through a coil, which then moves indoors where another coil releases it. (Yes, there’s sufficient outdoor heat even in the coldest weather.)

2) There’s Smoke Rising from the Outdoor Unit

Yes, we know this looks like a serious problem. But that isn’t smoke you’re seeing. It’s only water vapor. What’s happening is the defrost cycle of the heat pump is melting ice along the outdoor coil. Moisture forms along this coil when it absorbs heat from the air (the same way that moisture forms along the indoor coil when the heat pump is working in cooling mode). Because of the low outdoor temperature, this moisture will freeze. To prevent the ice from slowing down heat exchange, the heat pump shifts into a defrost cycle to heat up the coil and melt away the ice. Thus, the source of the water vapor you may mistake for smoke.

Of course, the heat pump may encounter ­real problems during the winter. You can depend on our expert technicians for heat pump repair services any time of the day or night.

Air Creations, Inc. serves Westfield, NJ. “We Do It Right Since 1987!”

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