When should I switch the thermostat to EMERGENCY HEAT for my heat pump air conditioner?
Wednesday, August 1, 2018
Don’t do it! The only reason to set your thermostat on emergency heat is if the regular heat is not functional. A heat pump is essentially a reverse cycle air conditioner, switching the flow of the refrigerant backwards on cold days to absorb outside heat and bring it into your home. Moving existing heat is more energy-efficient than generating new heat with an electric-resistance heat strip in the air handler (indoor unit) of the air conditioning system.
But the heat strip is installed to function on days when the outdoor temperature dips toward freezing and below, and there is not enough warmth in the air for the heat pump to work efficiently. An internal sensor in the system recognizes when this happens, and will switch on the heat strip automatically—which makes the “AUXILIARY HEAT” or “AUX HEAT” light on your thermostat come on, indicating that the backup system has been activated temporarily.
When you turn on “EMERGENCY HEAT” or “EMER HEAT,” you are turning on the heat strip and locking off the heat pump, which increases the cost of heating your home and is not a good idea.
Also see our blog posts How long does a home thermostat last? and Will closing doors reduce my heating and cooling costs?
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To learn more about heating and air conditioning systems, see these other blog posts:
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