How your new heat pump system works in winter

Posted on by Sunrise Mechanical Inc

How your new heat pump system works in the winter

Heat Pump Winter Use
There are some things you will notice that your new heat pump does when the temperature outside is below 38 degrees. The unit will go into a defrost cycle. This changes your heat to air conditioning which will then blow cold air out of the vents as if the air conditioner is on to defrost the outdoor coil, steam will come off of your unit, and water will run off the roof as the ice melts. This operation can occur in the early morning hours especially when the outside temperature is below 38 degrees for 30-40 minutes at a time and may occur frequently depending on the outdoor temperature. The colder it is outside and the colder you keep the inside of your home the more often it will go into defrost. When the defrost controls sense that the frost has been removed, the heat pump will automatically reverse and resuming the heating cycle. It is our recommendation that you keep the temperature inside your home above 72 degrees when the outside temperature is below 38 degrees. This will shorten the cycle. This is a normal operation of the unit. For more information on how a heat pump works GOOGLE How a heat pump works for more details.

Some have noticed this more in the newer heat pumps versus the older heat pump that was on the home. This is because of newer technology and the refrigerant has changed. Some will also notice theirs performs this operation more than the neighbors units. Everyone maintains a different temperature, lifestyle, and comfort level so it is almost impossible to compare your operation to theirs.

If you experience this in the early morning hours we recommend the following:

DO NOT LEAVE YOUR SYSTEM OFF ALL NIGHT: The unit will not catch up to your desired heat temperature. The unit will take an hour for every degree you are trying to heat.

DO NOT TURN OFF THE SYSTEM IN THE MIDDLE OF THIS CYCLE: Turning off the system will only delay the cycle. When the system is turned back on it will recall that it needs to finish the defrost cycle which will continue to blow cold air until the cycle is finished.


Try turning the unit up a degree or two before bed, especially on the nights there is a freeze warning. This helps keep the coil warmer as the unit is maintaining a warmer temperature inside the home, running more frequently.

If the unit does not start heating after the outdoor temperature increases to the mid 40’s and the sun melts the frost off the roof call our office at 623-583-7879.



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