Understanding Why a Heat Pump May Be Covered in Frost

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Have you ever found frost on the outside unit of your heat pump and wondered, "is this normal?" The answer is yes, it is normal. Here's why...

Why a Frosty Heat Pump is Normal

Refrigerant runs at about 10 degrees below the temperature of atmospheric air, which makes the outside unit colder. Water vapor is a component of air, and if the unit’s temperature falls below the dew temperature, the vapor condenses on the heat pump's surface and frosts. This is basically the reason for your frosty heat pump.

But heat pumps are built to handle this problem using a defrost cycle. Depending on the setting of the defrost timer, the reversing valve sends the heat that was originally intended for your home back to the outside unit. This causes the system to defrost. That’s why you find frost on the unit and when you check again after a while you don’t find it.

How Heat Pumps Heat Your Home While Defrosting

During defrosting cycle the heat pump heats your house using supplemental heat. The heat which comes from the coil is all used in defrosting. The frosting will happen in any season but it is highest during the winter.

What to Do When Your Heat Pump Doesn't Defrost

If your heat pump doesn’t defrost, there may be something wrong with the system, and you should have it checked by a professional. Left unchecked, unnecessary and costly damage could occur.  that needs to be checked to avoid damage to your system.

If your frosty heat pump isn't defrosting properly, contact us at McWilliams and Son Heating & Air today.