During cooler weather, you may notice that your heat pump has iced over. A small amount of frost on the outdoor component of a heat pump is normal, provided that after a few hours, the frost has melted. Heat pumps are equipped with a defrost phase to remove the frost buildup that occurs during certain weather conditions. If, however, ice begins to restrict airflow to the unit, or if frost remains for many hours, action should be taken quickly to prevent equipment damage.

How Does Frost Form on a Heat Pump?

All air contains water vapor, and when temperatures are between 20 and 40 degrees with humidity of 70 percent or higher, there’s a chance you’ll see that your heat pump has iced over a bit. The refrigerant in a heat pump is usually 10 to 20 degrees colder than surrounding air, giving water vapor a location to condense. In conditions where the temperature is below freezing, ice will form on heat pump coils.

The Defrost Cycle

A heat pump is designed to remove ice by reversing the direction of its refrigerant to begin a defrost cycle. The outdoor fan will shut off, allowing the refrigerant to become warm and melt the ice. This process usually takes less than 10 minutes. During this period, a heat pump operates in its secondary heating mode, typically electric resistance heat. Although these defrost periods are less efficient, damage to your heat pump will be avoided.

If Airflow to the Unit Is Blocked…

If you notice that your heat pump has iced over to a point where the airflow is restricted, its time to call an HVAC professional, as serious damage can occur to your unit in this situation. Ice or frost that remains for more than a few hours is also a warning sign that requires prompt attention.

Homeowners in the Shreveport area with a heat pump that has iced over can learn more about Pioneer Comfort Systems heating repair services or call 318-795-8000. We’ve been proudly serving Louisiana residents for 54 years.

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