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Can A Heat Pump Freeze Up?

Can A Heat Pump Freeze Up?

01 Jun, 2023

Heat pumps are efficient and versatile HVAC systems commonly used for both heating and cooling. However, like any mechanical device, they can experience issues that impact their performance. One common concern is the possibility of a heat pump freezing up. In this article, we will explore the causes behind a frozen heat pump and provide solutions to prevent and resolve this issue.

Understanding The Heat Pump's Defrost Cycle

Simply speaking, due to the moisture in the air, a heat pump's outside unit may develop frost or ice during colder weather. Heat pumps have a defrost cycle that periodically melts the ice accumulation in order to maintain peak efficiency. This defrost cycle is essential to ensure the proper functioning of the heat pump during the winter months.

Wholesale Domestic Hot Water Air Source Heat Pump

Wholesale Domestic Hot Water Air Source Heat Pump

What Causes A Heat Pump To Freeze?

Several factors can lead to a heat pump freezing up. Understanding these causes can help homeowners take preventive measures and address the issue promptly if it occurs.

Insufficient Airflow

One of the primary reasons for a frozen heat pump is restricted airflow across the outdoor coil. Dirty air filters, clogged vents, or trash near the outside unit are typical offenders. Heat transmission and avoiding frost formation depend on proper ventilation. Regularly inspecting and cleaning the air filters and outdoor unit can help maintain adequate airflow and prevent freezing.

Low Refrigerant Levels

Heat pumps rely on an adequate amount of refrigerant to operate efficiently. If there is a refrigerant leak or if the system doesn't have enough charge, the coil may freeze. When the refrigerant level is low, the coil becomes colder than usual, leading to ice formation. Having a professional HVAC technician inspect and recharge the refrigerant when necessary can prevent this issue.

Water Cooled Heat Pump Factory

Water Cooled Heat Pump Factory

Malfunctioning Defrost Controls

A faulty defrost control board or sensor can prevent the heat pump from initiating the defrost cycle when needed. As a result, excessive ice accumulation can occur on the outdoor unit, causing the heat pump to freeze up. Regularly testing and ensuring the proper functioning of these defrost controls is essential to prevent freezing.

Extremely Low Outdoor Temperatures

While heat pumps are designed to operate in cold climates, extremely low temperatures can still affect their performance. During severe cold spells, the defrost cycle might not be able to keep up with the ice development, leading to freezing. If you live in an area with frigid temperatures, taking additional precautions to protect your heat pump during winter is crucial.

How To Prevent And Resolve A Frozen Heat Pump?

Now that we understand the common causes of a frozen heat pump, let's explore the steps to prevent and resolve this issue.

Heat Pump Air To Water Factory

Heat Pump Air To Water Factory

Regular Maintenance

To guarantee optimal airflow and efficient operation, schedule periodic heat pump maintenance. Professional HVAC technicians can clean filters, conduct a complete system examination, and spot and resolve any problems before they result in freezing.

Clean The Outdoor Unit

Regularly clean the area around the outdoor unit, keeping it clear of debris, leaves, and vegetation. Additionally, ensure that the outdoor coil remains unobstructed to allow for efficient heat transfer.

Check Refrigerant Levels

Engage a professional HVAC technician to inspect the refrigerant levels regularly. They can identify any leaks or low charges and perform a refrigerant recharge and maintenance as needed to avoid freezing.

Test Defrost Controls

Regularly check if the sensor and defrost control board are working properly. If any components are faulty, replace them promptly to ensure the heat pump initiates the defrost cycle when required.

Consider Auxiliary Heat

In extremely low temperatures, activating the auxiliary or emergency heat option can provide supplemental heat when the heat pump struggles to keep up. However, it is essential to consult with a professional HVAC technician before using this feature to avoid potential issues.


While heat pumps are generally reliable, a frozen heat pump can disrupt the system's performance and efficiency. Follow these steps could effectively prevent and resolve a frozen heat pump. By the way, if you are looking for a new heat pump, AIROSD can help you. We are devoted to providing various heat pumps. Get in touch with us from more product details!

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