How To Fix Heat Pump Freezing Up In Winter: Solutions And Prevention

How To Fix Heat Pump Freezing Up In Winter

As winter sets in and temperatures drop, it’s essential to have a properly functioning heat pump to keep your home warm and comfortable. However, one common issue that homeowners face is a heat pump freezing up in the winter. This can lead to reduced heating efficiency and even complete system failure if not addressed promptly. In this blog post, we will discuss the causes of a frozen heat pump and provide you with some effective solutions to fix the problem.

Introduction Of Heat Pump

Heat PumpA heat pump is an energy-efficient heating and cooling system that relies on the transfer of heat between the indoor and outdoor units. During the winter, the heat pump extracts heat from the outdoor air and transfers it inside your home to keep you warm. However, there are several factors that can cause a heat pump to freeze up during the cold winter months. These factors can lead to reduced efficiency and potentially harm your unit if not addressed promptly.

Common Causes Of Heat Pump Freezing

Before we delve into the solutions, it’s important to understand the common reasons why heat pumps freeze up in the winter. Recognizing these causes will help you take the appropriate steps to prevent and resolve the issue.

Low Refrigerant Levels: Insufficient refrigerant levels can lead to the heat pump not absorbing enough heat from the outdoor air. This can cause the coil to become too cold, leading to ice formation.

Outdoor Temperature: Extremely low outdoor temperatures can cause the moisture in the air to freeze on the heat pump’s outdoor unit, leading to ice buildup.

Defrost Cycle Issues: Heat pumps have a defrost cycle that’s designed to melt any accumulated ice. If this cycle is not working correctly, it can lead to excessive ice buildup.

Poor Airflow: Insufficient airflow across the heat pump’s coil can result in reduced heat transfer and ice formation.

Dirty or Clogged Filters: A dirty or clogged air filter can obstruct airflow, leading to inefficient heat exchange and potential freezing.

Faulty Thermostat: A malfunctioning thermostat can cause the heat pump to run longer than necessary, increasing the risk of ice buildup.

Refrigerant Leaks: Refrigerant leaks can not only reduce the efficiency of your heat pump but also lead to freezing issues.

Inadequate Insulation: Poor insulation in your home can make it difficult for the heat pump to maintain the desired indoor temperature, leading to prolonged operation and freezing.

Now, let’s explore the solutions to address these common causes and fix a frozen heat pump.

Solution: Fixing A Frozen Heat Pump

Solution Fixing A Frozen Heat Pump1. Check Refrigerant Levels

Insufficient refrigerant levels can cause the heat pump’s evaporator coil to become too cold, leading to ice formation. To address this issue:

  • Contact a Professional: It’s crucial to have a licensed HVAC technician inspect and recharge your heat pump’s refrigerant. They can identify any leaks and ensure the correct refrigerant charge.

2. Maintain Proper Outdoor Temperatures

While you can’t control the outdoor temperature, you can take some steps to mitigate the effects of extreme cold on your heat pump:

  • Install a Cold-Weather Kit: Some heat pumps come with optional cold-weather kits that include a fan to help dissipate heat and prevent ice buildup.
  • Create Wind Barriers: Erect barriers or windbreaks around the outdoor unit to protect it from harsh winds and reduce the chances of ice formation

3. Check the Defrost Cycle

The defrost cycle is essential for melting ice on the outdoor unit. If it’s not working correctly, you can take the following steps:

  • Inspect the Defrost Control Board: A malfunctioning defrost control board may need to be repaired or replaced by an HVAC technician.
  • Ensure Proper Timing: The defrost cycle should be timed correctly. Consult your heat pump’s manual to adjust the timing if needed.
  • Keep the Outdoor Unit Clear: Ensure there are no obstructions around the outdoor unit that could prevent the defrost cycle from working effectively.

4. Ensure Proper Airflow

Good airflow is essential for efficient heat exchange. To improve airflow:

  • Trim Vegetation: Keep plants and shrubs near the outdoor unit trimmed to ensure proper airflow.
  • Clear Debris: Regularly check for leaves, debris, and snow accumulation around the outdoor unit. Ensure it remains clear of obstructions.

5. Clean or Replace Filters

Regularly changing or cleaning your air filters is crucial to maintaining proper airflow:

  • Inspect the Filters: Check the filters every 1-3 months and clean or replace them if they are dirty or clogged.
  • Follow the Manufacturer’s Recommendations: Refer to your heat pump’s manual for specific instructions on filter maintenance.

6. Verify the Thermostat

A faulty thermostat can lead to extended run times, increasing the risk of freezing.

  • Calibrate or Replace the Thermostat: If you suspect issues with your thermostat, it’s a good idea to have it calibrated or replaced by a professional.
  • Ensure Proper Temperature Settings: Set the thermostat to the desired indoor temperature to prevent the heat pump from running excessively.

7. Address Refrigerant Leaks

Refrigerant leaks not only cause freezing issues but also reduce the overall efficiency of your heat pump. To deal with refrigerant leaks:

  • Contact a Professional: A certified HVAC technician should identify and repair any refrigerant leaks. They will also recharge the system to the proper levels.
  • Consider a Leak Detection Kit: Some professionals use leak detection kits to pinpoint the exact location of refrigerant leaks for efficient repairs.

8. Improve Insulation

Inadequate insulation can make it challenging for the heat pump to maintain indoor temperatures and increase the risk of freezing.

  • Evaluate Your Home’s Insulation: Consider having a home energy audit to identify areas where insulation can be improved.
  • Seal Air Leaks: Seal any gaps or cracks in doors, windows, and walls to prevent heat loss and cold air infiltration.
  • Increase Attic Insulation: Enhancing insulation in your attic can significantly improve your home’s overall energy efficiency.

By addressing these common causes and implementing the provided solutions, you can effectively fix a frozen heat pump during the winter months. However, some of these tasks may require professional assistance, so it’s essential to consult with a licensed HVAC technician when necessary.

Preventing Heat Pump Freezing

Prevention is often better than cure. To minimize the risk of your heat pump working in winter freezing during winter, consider these proactive measures:

Regular Maintenance: Schedule annual maintenance with an HVAC technician to ensure your heat pump is in good working condition.

Change Filters: Follow a regular filter maintenance schedule and replace or clean filters as needed.

Insulate Your Home: Proper insulation can help your heat pump maintain indoor temperatures more efficiently.

Cold-Weather Kit: If you live in an extremely cold climate, consider installing a cold-weather kit to assist your heat pump in sub-freezing temperatures.

Clear Obstructions: Keep the area around your outdoor unit clear of debris, snow, and vegetation.

Monitor Thermostat Settings: Ensure that your thermostat is correctly calibrated and set to the desired indoor temperature.

Address Insulation Issues: If you identify areas in your home with inadequate insulation, take steps to improve it.

Regularly Check for Refrigerant Leaks: Keep an eye out for signs of refrigerant leaks, such as reduced heating efficiency, and promptly address any issues.

Understand Your Heat Pump: Read your heat pump’s manual to familiarize yourself with its operation, defrost cycle, and maintenance requirements.

By being proactive and maintaining your heat pump properly, you can significantly reduce the likelihood of it freezing up during the winter.


In addition to addressing the common causes of a frozen heat pump, it’s vital to emphasize the significance of preventive measures in maintaining the efficiency and longevity of your heating system. Taking proactive steps such as scheduling regular maintenance, changing filters, insulating your home adequately, installing cold-weather kits, clearing obstructions, monitoring thermostat settings, and promptly addressing refrigerant leaks can significantly minimize the risk of your heat pump freezing up during the winter months. By understanding your heat pump’s operation and maintenance requirements, you can ensure its smooth functioning and enjoy a cozy and warm home throughout the winter season. Remember, when in doubt or when tasks require specialized expertise, always consult with a licensed HVAC technician to ensure optimal performance and safety of your heating system. With proper care and attention, you can keep your heat pump operating efficiently and effectively, providing reliable warmth for years to come.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.