When Is It Time to Use the EM Setting on Your Heat Pump?

Written by BooAdmin on . Posted in Uncategorized

If you own a heat pump, you may have noticed a setting on the thermostat called “EM.” Leaving the EM setting on will not stop the unit from heating your home, but it can reduce the efficiency of your heat pump. Understanding the EM setting, and when to use it, can help you maximize your heat pump’s efficiency and can reduce your utility bills this winter.

How the Heat Pump Works

Heat pumps function by moving heat from one location to another location in order to control the temperature of your home. For example, when the air inside your home is too warm, refrigerant inside the heat pump coils will absorb the heat indoors and move it to the outdoors, thus cooling your home. This is the same process used by air conditioners and refrigerators to create a cooling effect.

When it gets cold inside your home, heat pumps reverse this process to push heat into the house. Heat from the outdoors is absorbed through the coils in the unit, and then that heat is transferred to your home through air ducts. The lower the temperature gets outside, the more difficult it becomes for your heat pump to transfer heat to your home’s interior.

As the heat pump’s job becomes more difficult, the unit begins to rely on a supplemental heat source to keep your home warm. This supplemental heat source is not as efficient as the heat pump itself, but it will help keep your home warm and help your heat pump keep up with the demand for warm air.

What the EM Setting Does

If your heat pump breaks, this supplemental heat source can be used exclusively to heat your home. Turning on the EM setting activates the supplemental heat source.

Heating your home via the EM setting is far less efficient than heating your home with the heat pump. However, homeowners who find that their heat pump is disabled by malfunction or mechanical problems may find that this less efficient method of heating is better than not heating their home at all.

When to Use the EM Setting

Homeowners who notice that their heat pump is no longer able to keep their home warm by using the heat pump in the usual way can turn on the EM setting while waiting for their HVAC contractors to arrive. Symptoms of a broken heat pump include:

  • The unit is blowing cool air instead of warm air
  • Ice has built up on the exterior unit
  • The unit cycles frequently but does not warm the home
  • Some rooms are much warmer or cooler than other rooms

Before turning to the EM heat setting, always remember to check the thermostat, make sure the breaker is on, and open up the vents. If these basic trouble shooting steps don’t help, then it’s a good time to use the EM heat setting and call for help.

Maintaining Your Heat Pump

The best way to avoid problems with a heat pump and prevent unnecessary use of the EM setting is to get your heat pump serviced at least once annually. Having an HVAC contractor look at your heat pump once per year can help catch mechanical problems in their early stages. If your HVAC contractor notices a problem that can be repaired, getting that issue addressed can ensure that the heat pump keeps functioning throughout the year.

It’s also important to replace the air filter for your HVAC system at least once every three months. Doing this will prevent dirt and debris from building up in the system, which can prevent mechanical problems.


At Lakeside Heating & Air Conditioning, we help homeowners in Arvada, CO to maintain their heating and air conditioning units. Whether you’re in need of service for your furnace, heat pump or air conditioner, or you simply want a tune up to ensure that your unit continues to work throughout the year, we can help. Contact us today at 303-421-3572.

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Arvada, CO 80002
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