Heat Pump Freezing Up In Summer: What You Need To Know

Homeowners are aware of how crucial their heat pump is in a home. It is versatile in that it can keep you cool in the summer and warm in the winter. Like other equipment, it can experience problems from time to time. For instance, a common issue homeowners contact us about is a heat pump freezing up in summer. Keep reading to learn about frozen heat pumps and several tips to keep this problem from happening.

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Heat Pump Freezing Up In Summer: What You Need To Know

frozen heat pump in summer

If you have a frozen heat pump, don’t panic! It isn’t as severe a problem as you may think. There are a few reasons that can cause this heat pump issue, and we’ll list them here in this article.

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How Does A Heat Pump Work?

Heat pumps help regulate your home temperature. It operates by transferring heat from one area to another. During the hot months, your heat pump moves heat from inside your home to the outside so you can enjoy a cool and comfortable home. This cycle can be reversed in the winter so your home stays warm and comfortable.

Related Article: Air Conditioner Noises To Be Aware Of

What Are The Signs Of A Frozen Heat Pump?

heat pump operation

The first step in heat pump assessment is to determine if it is frozen or not. The good news is that there are some easily recognizable signs of a frozen heat pump, such as:

  • Heat Pump Is Not Working: If your home fails to cool down, your heat pump may not be working. This is an obvious sign of a heat pump problem. A frozen heat pump cannot work as it should and it won’t be able to cool your home. 
  • Ice On The Heat Pump Unit: Another frozen heat pump symptom is ice on your outdoor unit, even in the summer heat. This typically indicates that there are frozen coils that should be thawed.
  • Water Leaking From The Unit: Water leaking out of the outdoor unit likely means there are frozen coils, and the unit is thawing out. Take a walk outside and check your HVAC unit for these or other unusual signs.
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Reasons Your Heat Pump Freezes

It is frustrating to have a frozen heat pump, but knowing the reason behind it can help. Here are several causes your heat pump freezes:

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Outdoor Temperature

The heat pump may not work correctly if the temperature outside is too warm. Your system cannot go cooler once the outdoor temperatures reach around 100 degrees Fahrenheit.


image of a mother and daughter feeling uncomfortable due to heat pump freezing up in winter

Humidity, like temperature, pushes your heat pump to work harder. High humidity causes the heat pump to operate harder to eliminate moisture in the air. This can result in condensation buildup on the coils, which can freeze over time.

Doors & Windows

Warm air can get inside your home via open doors or windows. This forces your heat pump to work nonstop to keep your home cool. This hastens wear and tear, and your unit will eventually get damaged.

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Related Article: Why Is My Air Conditioner Running In Short Bursts?

Heat Pump Thermostat Setting

A thermostat that is set too low will cause the unit to operate continuously to achieve your preferred temperature. This can result in frozen coils.

Broken Thermostat

image of a homeowner feeling hot and uncomfortable due high humidity and broken heat pump

A faulty thermostat causes your heat pump to switch on and off erratically. This can also cause the coils to freeze up.

Refrigerant Levels

Refrigerant is a substance that makes your heat pump work. Coolant problems can cause the entire system to stop working as it should. For instance, low refrigerant levels in your heat pump can result in a frozen unit. Remember that only an HVAC professional can help you resolve this issue. Refrigerants are harmful to pets and humans, so a unit that is leaking refrigerant should be addressed immediately. It can cause eye and skin irritation and even death. It can also lead to a frozen heat pump. Never try to clean or fix a heat pump that leaks coolant on your own.

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Dirty Heat Pump Coil

image of a dirty heat pump coil

The refrigerant is in the heat pump’s evaporator coil. The system works when the refrigerant absorbs and cools hot air. A dirty evaporator coil means the unit cannot operate efficiently.

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Heat Pump Compressor

The compressor is the component helping the refrigerant move around the heat pump. A malfunctioning compressor means the unit cannot cool your home, so your heat pump may start to freeze.

HVAC Airflow

image of an hvac air filter replacement

A heat pump requires proper airflow to operate efficiently and effectively during home cooling. Having reduced or blocked airflow can cause the unit to freeze. Here are several ways your airflow can be restricted:

  • Air Filter: Dirty air filters can restrict air flow, causing the heat pump to freeze. Air filters should be replaced regularly throughout the year to help your unit operate properly.
  • Return Vents: All vents around your home should be open and unblocked. Check to see if furniture or other objects are in front of the ducts. If so, remove them.
  • Outdoor Unit: Proper perimeter clearance around the outdoor unit is needed so it can function properly. 
  • Blower: A broken fan, fan relay switch, or blower can also restrict airflow. It can also lead to frozen heat pumps in the summer.

Keep in mind that it is crucial to have proper airflow to ensure your heat pump works as it should.

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What To Do If Your Heat Pump Stops Working

If you think you have a frozen heat pump, the first step is to turn off the unit. Once this is done, let it thaw for several hours. If the unit still doesn’t work after letting it thaw for a few hours, call an HVAC professional to come and check it. A certified HVAC contractor will examine your unit to find out the root cause of the problem. They will also fix or replace faulty components.

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What Can You Do To Prevent Your Heat Pump From Freezing Up In The Future?

Heat pumps are prone to freezing, but here are several tips you can do to prevent it:

  • The thermostat should remain at the same temperature setting. Don’t turn it up and down often. 
  • Conduct regular air filter replacements. Dirty filters restrict the airflow, resulting in a frozen heat pump. You can help your unit function properly when you replace the air filter regularly, year-round.
  • Make sure the vents are clear. Keep the vents in your home open and unblocked by furniture, plants, or other objects.
  • The outdoor unit of your heat pump should have adequate clearance around it.
  • Book regular check-ups for your heat pump. Call a reliable HVAC company twice a year to service your system. It should be tuned up for both heating and cooling.

If you have a frozen heat pump, turn it off and call an HVAC professional.


It can be frustrating and confusing when your pump freezes up in summer. However, you can troubleshoot this issue when you have the right knowledge. Your heat pump will run back up in no time with the help of your local, experienced HVAC technician.

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Lake Region Energy provides exceptional heating and cooling services in Maine and New Hampshire. We have the best professionally certified contractors who can perform top-quality heating and cooling services, like heat pump maintenance, furnace replacements, air conditioner installations, and more. All our techs have the knowledge, skills, and experience to service your HVAC system accurately.

For the region’s most competitive HVAC service rates, call Lake Region Energy. Our tune-up services can help you increase home comfort and energy efficiency and reduce heating and cooling costs. If your HVAC system requires repairs or replacements, we can recommend the most suitable solutions for your home and budget. We back all our work with a guarantee. Schedule your next service appointment by calling Lake Region Energy today. We offer free, in-home estimates.

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For more information about our fuel deliveries and HVAC services, be sure to contact Lake Region Energy. You can click here to contact us, or you can call us at (207) 839-5500 to find out more. We offer a full line of heating and cooling repairs, maintenance services, and installations.

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