Learn why your heat pump freezes in winter and how to fix the problem.

Heat pumps are proven to be one of the most resilient and efficient home air conditioning systems, and for this reason, many consumers find that freezing of their heat pumps is not typical. Freezing of the heat pump unit is normal to a certain extent, however, excessive icing can damage the system and even cause it to shut down.

In this article, we'll take a look at why and when freezing heat pumps are normal and when you should contact a professional technician. We will also share practical tips on how to act in such situations.

Why does a heat pump ice up in winter?
The formation of a small amount of ice during the winter months is actually normal for heat pumps, especially during the colder months. The ice that forms is a result of the condensation released during the system's operating process.

The heat pump operates in cycles and a layer of frost can form on it during operation. This should not worry you as once the unit reaches a certain temperature, the system should switch itself to defrost mode. If the condensing fan motor can draw air into the unit, it means everything is fine.

An efficient heat pump operates in cycles. Periodically, when it is cold outside, the coil collects a layer of frost or thin ice. Then, when the unit reaches a certain point, the defrost cycle should turn on automatically to keep the heat pump running normally. There is no need to worry as long as the condensing fan motor can draw air into the unit.

How does the defrost mode of the heat pump work?
The defrost mode protects your heat pump from damage, and it only activates when needed, and the heat pump has a built-in temperature sensor that triggers the defrost cycle.

This defrost cycle has an average duration of 10 to 15 minutes. Usually, its activation is sufficient to keep the heat pump running smoothly and efficiently during the winter.

In which cases is freezing of the heat pump considered problematic?

It is possible that the ice does not melt fast enough during the defrost process. If this happens, the heat pump is likely to fail. In the event that the coils are iced over, they will not be able to operate efficiently and the system will not produce the required heat.

Also, ice buildup can lead to broken fan blades, refrigerant leaks and other malfunctions. If you notice that your heat pump isn't defrosting within 15-20 minutes, it's best to seek the help of an HVAC technician.

Here are the signs when you should contact a professional technician:

  1. The entire outdoor unit of the heat pump is covered with ice
  2. The outdoor unit continues to be iced for a long time
  3. The top of the heat pump and the internal coil are frozen
  4. Heat pump does not activate defrost mode


Why does the heat pump ice up?
Ice forming and blocking the heat pump from functioning properly is a sign that there is a malfunction in the system. It could be:

  1. Low refrigerant level
  2. Contaminated air filter
  3. Defective thermostat, temperature sensor or other element of the heat pump unit
  4. Fan blades or coils blocked by ice
  5. There is a malfunction in the outdoor fan
  6. There is a malfunction related to the reversing valve


What to do if the heat pump is frozen?
In case your heat pump freezes you can follow these steps:

Check that the filter is not dirty. If so, clean it and reactivate the system. If the defrosting process does not resume and the ice does not melt, continue with the next step.

Check the condition of the condenser fan.

Clear any obstructions around the heat pump. If there are accumulated leaves and debris, remove them. Turn on the fan manually. If no air is coming out through the fan vents, the fan motor may fail.

You should seek the help of a professional HVAC maintenance company and relay the information you already have about the system's condition.

If you want a quality heat pump, trust the quality that Midea offers. Midea has a long and proven track record in the air conditioning industry. Find out more about the models we offer here. Contact us if you need professional advice.