Freezing of the Outdoor Unit of your Air Conditioner and Heat Pump – A Normal Phenomenon

When the temperature drops, the outdoor unit of your air conditioner or heat pump can freeze. This is a normal process and is part of the system's operation. Modern heat pumps and air conditioners are designed to deal with this and have an automatic defrost cycle. We are happy to explain why outdoor units freeze, how the defrost process works and when action is required.

Why does the outdoor unit freeze?

The outdoor unit of an air conditioner or heat pump extracts heat from the outside air. During this process, moisture in the air can condense on the heat exchanger and then freeze at low temperatures. This happens mainly in:

• Low outside temperatures around or below freezing.
• High humidity.
• Air circulation that is temporarily reduced by cold.

The defrost cycle: how does the system solve this itself?

Heat pumps and air conditioners have a built-in defrost program. This means that the system will briefly reverse itself at set times and send heat to the outdoor unit to melt the ice. This happens automatically and is an essential part of the operation of the appliance. So you don’t have to worry if you see ice forming occasionally.

During defrosting, steam may form. This is completely normal and is often mistaken for smoke, but it is simply water evaporating as a result of the heat given off by the unit. This is part of the process and is not a cause for concern.

When should you intervene?

Although frostbite is normal, in some cases it can become a problem. Be aware of the following situations:

• The unit remains frozen for a long time and does not return to normal operation.
• The defrost cycle is not working properly , which may indicate a malfunction.
• Water cannot drain properly , causing it to refreeze and cause damage.
• A lot of snow or dirt accumulates around the unit , which can disrupt its operation.

What can you do if the outdoor unit remains frozen?

1. Leave the unit alone – In most cases the system will resolve itself.
2. Check the water drainage – Make sure that melt water can drain away properly.
3. Remove any accumulated snow or leaves – This will prevent additional ice formation.
4. Call a professional if the problem persists – If the unit does not defrost or continues to malfunction, there may be a technical problem.

Conclusion

Freezing of the outdoor unit of your air conditioner or heat pump is a normal phenomenon and no reason to panic. Thanks to the automatic defrost cycle, this process is controlled automatically. Only if the unit remains frozen for a long time or no longer functions properly, it is wise to check whether there is a problem. Are you in doubt? Contact a specialist for advice!