What does it mean when my air conditioner or heat pump is iced up in the summer?

Commonly HVAC Problems and Solutions Air conditioner or Heat Pump with ice on it in summer

It is possible even common to see ice on your heat pump or air conditioner in the summer. Boer Brothers Heating and Cooling sees a hundred of them a summer. But it means something in your system isn’t well. We use the word system because that is really what we are dealing with. There is an outside unit, an inside unit, some copper tubing which connects them and a system of air delivery conduits called ducts (not ducks). Ice on your system is a symptom which could mean many things. Some of these issues homeowners can fix themselves and save some time and coin, and some that do require one of those smiling guys in the blue shirts.

Step one is to turn off the system. “What? but it is 90 degrees in the house already.” Exactly, the system isn’t doing its job. The ice on the unit makes it impossible for the heat transfer to happen so it causes loss of cooling. One typical response is to turn the thermostat temperature down but usually this just exasperates the issues. Even in a working system we suggest leaving the thermostat at 70 or above. It reduces that chance of the unit sweating into the ductwork and freezing up the unit.

If you are interested in doing a little initial detective work check these things before calling in a service provider.

Is the thermostat set too low? (try turning off the unit for a few hours and then restart it after raising the thermostat to above 70 degrees)

Even if there is an issue this will usually get you a few hours of cooling as the ice slowly builds back up.

Do you have a dirty air filter

It is easy to forget to change those suckers. Every 30 days they should be changed. More often during pollen season or if you have had some type of dirt creating event in your home, like construction or the grand kids visiting over the Easter Holiday. A dirty filter doesn’t allow enough air flow. Air flow is moved across the coils to transfer heat. No air flow no heat transfer. This creates ice.

Closed Vents

Same issue, no air no heat transfer.

Running air conditioner with windows or doors open

One of the great things about air conditioning is that it takes humidity our of the air. The 10-20 degrees of cooling is nice but the lower humidity is really the key to a livable space here in the south. Leaving the windows open introduces lots of humidity into the space. The cooler temperatures of the indoor space forces the moisture out of the air because warmer air can hold more moisture than cooler air.

If you’ve defrosted your system, checked your air filter and turned the AC back on without improvements in your system’s operation, then you need to check with a professional. It may take some time for ice to form again, making it important to continue to monitor your coil for a few days. If you detect ice, you should make that call for professional diagnostics. Be sure to turn your system off again to avoid damage.

Issues that require a pro

Low refrigerant charge

Without enough refrigerant that heat transfer doesn’t happen efficiently enough. This can cause the unit to ice up. The refrigerant circuit is closed, none should be escaping so if it is low, your system is either losing some gas or it never was properly charged. You will need to have your refrigerant level measured the piping system checked for leaks and repaired if necessary and then recharged to the proper levels.

Refrigerant Restriction

The same problem can happen if somewhere in your piping system there is a blockage. Again we will need to check for the restriction and replace the piping where it exists or the replace the capillary tube.

Bad Fan Motor or Fan Relay

If your fan is not working or the electronics that run the fan are not providing power to it than there is not airflow. The heat transfer doesn’t happen and again ice can build up. The fan or the relay or both may need to be replaced

Thermostat Issues

Issues with the defrost cycle which is controlled by the thermostat can lead to ice accumulation. The thermostat may need to be replaced.

Dirty Indoor Coil

A very dirty indoor coil can also create issues with heat transfer