Heat Pump: How to Defrost It During Winter

December 15, 2021

When the cold winter weather hits, it pays to have an energy-efficient heating system. One of the best options for those who live in mild environments is a heat pump. Instead of burning fuel to create heat, these systems simply transfer heat from the air or ground outside into your home.

Why Does My Heat Pump Freeze Up?

To understand why your heat pump freezes up, you first need to know how it runs. Your heat pump utilizes a substance known as refrigerant. This substance moves the heat from the air or ground outside into your home via the condenser coils. To do this, the refrigerant needs to be around 20 degrees colder than the air outside of your home.

When the air outside starts to dip down around 20 to 40 degrees, it can cause the moisture on the exterior components of your heat pump to freeze. Increases in relative humidity also play a role in how quickly your heat pump freezes up.

The Defrost Cycle

All heat pumps are designed to have a defrost cycle. Whenever your system senses that it's starting to freeze up, it will switch to the defrost cycle. During this cycle, the heat transferred from outside is essentially retransferred to the condenser coils in your outside unit.

This works to melt the ice that has formed over the condenser coils. This process typically takes around 30 minutes. During this time, you'll notice steam coming from your outdoor compressor unit. That's completely normal as the ice has melted off.

Tips For Defrosting Your Heat Pump

Every now and then, your heat pump may not switch over to the defrost cycle. Or, it may experience another malfunction that causes unwanted ice buildup on your exterior HVAC unit. You can manually defrost your unit in just a few simple steps.

To get started, you'll want to turn off your heat pump at the circuit breaker. Next, use your garden house to spray the heat pump with water to melt the ice. Avoid attempting to chip or hammer the ice away, as you could cause damage to the unit. Once the ice has melted, turn your heat pump back on at the circuit breaker.

If there is still some ice present on your unit, you'll want to turn your unit to 'Fan' mode. Let it run in this mode until all the ice melts away. It's always a good idea to assess why your system froze over in the first place. One common culprit that many homeowners find is an ineffective gutter that spills excess water onto the exterior heat pump unit. Fixing the faulty gutter can prevent this problem from happening again.

Contact Us Today

If you're still experiencing problems with your heat pump, it's best to call in our HVAC professional at Master Mechanical. They can assist in determining the root cause of why your heat pump keeps freezing up and why your defrost cycle isn't working.