Why Is There Smoke Coming from My Heat Pump? | WM Henderson

Why Is There Smoke Coming from My Heat Pump?

frost-pattern-on-windowHeat pumps are becoming more common in our area as homeowners discover their advantages. Heat pumps provide two-in-one comfort, with powerful cooling for the summers and energy-efficient heating for the winters. Homes without natural gas connections that can’t use gas furnaces for heat benefit from the cost-saving operation of a heat pump. Compared to the cost of running an electric furnace, a heat pump is a huge annual money-saver.

Even though heat pumps operate similarly to air conditioners (we’ll talk more about this below), there are some important differences. If this is your first winter with a heat pump, you may be in for a few surprises when it runs–like seeing smoke coming off the outdoor unit.

First, don’t worry—there’s probably nothing wrong

We want to assure you up front that there’s no need to panic. Seeing smoke from the outdoor heat pump cabinet probably doesn’t mean anything is wrong, like the heat pump motors catching fire or a massive electrical short. Not only is this part of the heat pump’s regular operation, it isn’t even smoke! You’re seeing steam from the heat pump as it goes through the defrost cycle.

To explain, we have to look at what a heat pump does during the winter. It runs like an air conditioner in reverse: the refrigerant circulating through the system draws heat from the outdoors and then releases it indoors, going through evaporation and condensation. (Yes, there’s enough heat outside even during our Pennsylvania winters to warm up an entire house. Heat pumps are getting more effective at this job with each new model.)

A heat pump runs into difficulty as it absorbs outdoor heat: it creates water condensation along the outside unit’s coil, and this water will freeze during a cold day. Ice along the coil makes it harder for the coil to do its job. The heat pump is equipped with a way to fix this. It periodically shifts into a defrost mode to melt the ice. The heat pump switches back for a short time to release heat from the coil to melt off the ice. This process makes a lot of noise, which might alarm a new heat pump owner. It’s also what causes the “smoke” to appear. It’s just steam from the melting ice. The heat pump is doing what it’s supposed to so your home continues to receive warmth.

You can expect to see some frost on your heat pump’s outdoor cabinet. This is normal and you don’t need to worry about it. We recommend you clear away any snow drifts that have built up against the cabinet, as this can create a block the defrost mode won’t be able to fix. These simple steps—and remember to schedule maintenance for the heat pump each fall before the cold arrives—will keep your comfort system working in prime shape for years.

If it turns out you ­do have real smoke coming from your heat pump, or you need any assistance with your home heating in Havertown, PA or elsewhere in our service area, just call us! We offer heating services such as furnace repair, boiler installation, and radiant heating system maintenance.

Wm. Henderson Plumbing, Heating & Cooling Inc. serves Delaware County and The Main Line, PA.

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