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Why Is My Heat Pump Icing Up?

Heat pumps are highly efficient heating and cooling machines. Sometimes during the winter, the outdoor condenser collects a layer of ice. Why does this happen? Should you be concerned when your heat pump ices up?

Why Is the Heat Pump Freezing Up & Should I Be Concerned?

Even cold, dry air contains water vapor. When the vapor is exposed to a temperature below dew point, it changes from a vapor into a liquid. When dew point is also below freezing, the liquid water turns to ice. This is the reason dew forms on grass in the summer and frost forms in the winter.

The perfect condition for a heat pump to ice up is when outdoor air is between 20 and 40 degrees and relative humidity approaches 70 percent or higher. These conditions are common during New Jersey winters.

A little bit of frost is completely normal. Most heat pumps today have a sensor to tell it when ice is forming. Before it becomes too thick, the defrost cycle automatically sends heat back through the outdoor coil to thaw the ice.

What to Do

If you check your heat pump and see a thin layer of ice starting to form, check back later to see if it’s still there. As long as the ice doesn’t linger, you have nothing to worry about. However, you should become concerned if the entire unit becomes encased in ice, including the top and inside of the unit. If you see this type of ice buildup happening, call a heating and cooling expert to address the problem quickly because something is probably wrong with the defrost cycle. Running a heat pump with a thick layer of ice can:

  • Decrease efficiency
  • Damage the equipment
  • Compromise comfort in your home

Please understand that it’s normal for a heat pump to stop heating your home for two to 10 minutes at a time when the weather is around freezing. This is the defrost cycle in action. If you notice this type of behavior from your heat pump, it’s working just like it should. That said, we do recommend using a backup heat source during the cold months for when temperatures drop into the extremes.

Heat Pump Repair & Replacement in Central NJ

Since 1977, Arctic Air Conditioning has been providing heat pump repair and heat pump replacement in Middletown, Princeton and surrounding areas in New Jersey. For more help figuring out the reason behind your heat pump icing up, contact us today!

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