Understanding the Defrost Cycle in Cold Weather

If you’ve noticed your outdoor unit pausing or emitting steam during freezing conditions, don’t worry,  it’s likely in defrost mode, a normal and essential part of how your heat pump or reverse cycle air conditioner operates in winter. When outdoor temperatures drop below zero, moisture in the air can freeze on the outdoor coil, restricting airflow and reducing efficiency. To maintain performance and prevent damage, the system automatically activates a defrost cycle.

During this process, your unit temporarily reverses operation to warm the outdoor coil and melt away any ice buildup. While in defrost mode, you may hear a slight change in sound, notice a temporary stop in warm air, or see steam rising from the unit,  all of which are completely normal.

Once the cycle completes (usually within 5-10 minutes), the system returns to heating mode. This feature ensures your air conditioning system remains efficient and reliable, even in Canberra’s coldest months. If you're experiencing extended or frequent defrost cycles, it may be a sign your unit needs servicing, and our expert team is here to help.