The defrost cycle is activated when the temperature of the outdoor coil drops below 32 degrees. At this temperature, frost can form on the coil, which can cause damage if it builds up. This is where the defrost cycle comes in. Your heat pump will switch to cooling mode to warm up the coil and melt the ice.

The heat pump defrost mode is a self-preservation feature that keeps the unit running properly when the unit’s coil temperature dips below freezing. In most instances, a system running in defrost mode isn’t a heating and cooling emergency.

When Does A Heat Pump Go Into Defrost Mode?

You’ll know the defrost cycle is activated when the heat pump switches from heating to cooling. You may hear the reversing valve when this occurs.

Another sign the defrost cycle is running is the indoor unit will run but the outdoor fan will be off. The cycle lasts from 5 – 15 minutes and should not affect the temperature inside your home.

When Should You Be Concerned?

As mentioned above, the defrost cycle starts when the outdoor coil reaches 32 degrees or below. The defrost cycle should not be running in warmer temperatures or running for an extended period of time. If either of these instances are occurring, your unit should be inspected.

How To Prevent Issues With Your Heat Pump

The average lifespan of a heat pump in Massachusettes, and surrounding areas is 10 – 12 years. To get the most out of your system and keep it running efficiently, look into a preventative maintenance plan.

There are many benefits to having your system checked annually. From simple pleasures like cleaner air to saving possibly tens of thousands of dollars on a premature replacement.

Minor issues can be found before they become major problems. Emergencies can be prevented, preserving your comfort, especially during extreme temperatures. Also, the lifespan of your system can be extended to provide peace of mind for a decade or more.