Why Is My Heat Pump Freezing Up in Summer?

Home > Blog > Why Is My Heat Pump Freezing Up in Summer?
Why Is My Heat Pump Freezing Up in Summer

Heat pumps are multipurpose systems providing both heating and cooling for your home or business. They work by transferring heat from one place to another, making sure your space remains comfortable throughout the year. 

However, it can be alarming if your heat pump freezes up during the summer months. Understanding why this happens will help you maintain the efficiency and longevity of your heat pump. 

Can a Heat Pump Freeze Up?

Yes, a heat pump can freeze up, even in the summer, resulting in a frozen coil. When this happens, address the issue promptly to avoid further damaging the system. A frozen heat pump can lead to reduced efficiency, increased energy bills, and even complete system failure if left unresolved.

What Causes a Heat Pump To Freeze?

Several factors can cause a heat pump to freeze and disrupt the heat exchange process. One of the most common reasons for insufficient airflow is a dirty filter. When filters become clogged with dirt and debris, air cannot flow properly through the system, leading to ice formation on the coils. Similarly, if furniture, dust, and other obstructions block vents or registers, airflow is restricted, causing the heat pump to freeze. Dirty coils can also restrict airflow and cause similar issues.

Refrigerant is essential for the heat pump to transfer heat effectively. If the refrigerant level is low, the evaporator coil can become too cold and freeze. Signs of low refrigerant include a decrease in cooling efficiency, hissing or bubbling noises, and ice formation on the refrigerant lines.

The defrost cycle melts any ice that forms on the outdoor coils. If this cycle is not functioning correctly, ice can accumulate and cause the heat pump to freeze. Problems with the defrost thermostat, timer, or control board can lead to a malfunctioning defrost cycle.

Why Is My Heat Pump Freezing Up in Summer?

The heat of summer often brings high humidity, which can lead to increased condensation on the coils. If the moisture doesn't drain properly, it can freeze and cause the heat pump to ice up. Using a dehumidifier can help manage indoor humidity and prevent freeze-ups. 

Dirty coils and blocked return vents can also contribute to freeze-ups. Regular maintenance tasks such as cleaning air filters, checking refrigerant levels, and making sure the defrost cycle works can help to prevent freeze-ups in hot weather.

When To Call a Professional

Sometimes, professional assistance is necessary to resolve heat pump issues. Call a professional if you notice:

  • Persistent ice buildup despite regular maintenance
  • Strange noises or smells coming from the heat pump
  • A significant decrease in cooling efficiency
  • Any signs of refrigerant leaks

Attempting DIY repairs without proper knowledge can be risky and may cause further damage to your system. HVAC professionals have the expertise and tools needed to diagnose and fix the problem.


Understanding why your heat pump freezes up in summer and taking preventive measures can help you maintain a comfortable and efficient environment in your home or business. Regular maintenance, proper airflow, and humidity control are key to preventing freeze-ups. If you encounter persistent issues, don't hesitate to call a professional to make sure your heat pump is functioning optimally. 

If your heat pump is freezing up or if you need regular maintenance to keep it running smoothly, contact Barnard Heating and Cooling today. Our expert technicians are ready to help you with all your HVAC needs. Schedule your service appointment now and keep your home cool and comfortable all summer. 

Copyright Barnard Heating and Cooling | Privacy Policy