The Effects of Freezing Rain on an Air Conditioner

Identification

• Freezing rain refers to any rain that falls when it’s freezing. The rain becomes ice before it hits the ground, and it can cause structural damage. When ice coats objects thicker than 0.2 inches, they are susceptible to damage. During the winter, it’s normal for some ice and water to accumulate on the unit -- but when the ice is thick and sits for an extended period of time, the damage can be costly.

Effects

• Heating and cooling units will naturally go through a defrost mode when they get too cold. Most models, especially newer ones, have internal thermometers that can monitor the unit’s temperature. The defrost cycle should melt the ice, but if ice is blocking the transfer between the coils, the defrost cycle won’t turn on. If the defrost system can’t turn on and the unit continues to run, the compressor could be damaged. You might also have to replace or clean the coils once the freezing rain finally does melt.

Prevention

• When you hear reports of freezing rain, cover your unit with a tarp, if possible. As soon as you notice ice on the air conditioner, turn it off and do what you can to remove the ice. Keep any debris or snow away from the unit so that the water has somewhere to drain off. Also, make sure the unit isn’t under or near the gutters, as this could cause more freezing rain to drain onto the air conditioner. If the gutter is near or over the unit, make sure it doesn’t leak onto the air conditioner, and repair any cracks that do leak. You can use a garden hose to remove ice. Do this as soon as you can, before the ice gets too thick and harder to remove.

Warning

• Never try to remove the ice with a sharp object. Not only could you hurt yourself if it slips, but the refrigerant coolant coils in the air conditioning unit are easily damaged, and can be costly to replace.

Considerations

• If you remove the ice and it comes back, or if you can’t defrost the ice due to a mechanical failure, contact an HVAC specialist to check the unit’s defrost mode or to see if the water from the freezing rain damaged the unit.