Heat Pump Not Cooling? 5 Common Heat Pump Issues and How to Fix Them

Heat pumps are one of the most energy-efficient solutions for both heating and cooling homes. In fact, the Department of Energy estimates that heat pumps can be between 30% to 60% more efficient than traditional cooling and heating systems.

But like any mechanical system, heat pumps are not immune to problems. Understanding common heat pump issues and knowing how to troubleshoot them can save you time, money, and discomfort. 

In this article, we discuss the five most common heat pump problems, and provide insights on how to fix them.

What Is the Life Expectancy of a Heat Pump?

A properly maintained heat pump has an average lifespan of 15 years, with newer models being able to last for up to 20 years.

A heat pump’s operational life depends on how often it gets used, whether it’s regularly and properly maintained, and the environmental conditions where it operates. Generally speaking, heat pumps have reduced performance and struggle to operate in colder weather conditions, when the outside air temperature drops to below 25 degrees Fahrenheit. 

5 Common Heat Pump Issues

1. Heat Pump Not Cooling or Heating

One of the most frequent complaints with heat pumps is a noticeable decrease in heating or cooling efficiency. Signs include uneven temperature distribution, inability to reach and maintain the desired temperature, or higher power consumption.

Potential Causes:

• Dirty or clogged air filters: Dirty filters restrict airflow, making the heat pump work harder to achieve the desired temperature.
• Refrigerant issues: Low refrigerant levels or a leak in the refrigerant line can severely affect the heat pump’s ability to transfer heat effectively.
• Broken thermostat: Incorrect thermostat settings or a malfunctioning thermostat can cause temperature inconsistencies.

How to Fix:

✔ Clean or replace air filters: Regularly clean or replace air filters to ensure proper airflow and system efficiency. Check out our guide to cleaning or replacing an air filter.

✔ Professional inspection: If the issue lies with refrigerant, have a professional HVAC technician inspect the unit. Only they are qualified to replenish refrigerant levels, or repair refrigerant leaks.

✔ Check the thermostat: Recalibrate the thermostat to ensure accurate temperature readings. If the problem persists, the thermostat may need to be replaced.

2. Icing or Frost Accumulation

Another common issue with heat pumps is ice or frost formation on the outdoor unit. This is particularly common during winter. 

Accumulated ice can hinder the heat exchange process and reduce the heat pump’s performance, causing it to work harder and shortening its lifespan while increasing your bills.

Potential Causes:

• Broken Defrost control: A malfunctioning defrosting system can result in excessive ice buildup on the outdoor coil.
• Dirty coils or airflow obstructions: Restricted airflow due to dirty coils or outdoor debris can cause temperature imbalances and ice accumulation.
• Refrigerant problems: Incorrect refrigerant levels or issues with the refrigeration cycle can also contribute to frost formation.

How to Fix:

✔ Check Defrost controls: Ensure that the defrosting system is activated and functioning. If the problem persists, defective components may need to be replaced.

✔ Clean coils and clear obstructions: Regularly clean the outdoor coils, and make sure the outdoor unit is free of debris that can hinder proper airflow.

✔ Professional inspection: If icing persists, consult a professional to inspect and address any refrigerant-related issues.

3. Unusual Noises

Strange or loud noises emanating from the heat pump can be a cause for concern. Different sounds can indicate various issues, ranging from minor problems to potentially significant issues that can damage the unit.

Noise types and possible causes:

• Banging or clanking: These can indicate loose or damaged parts within the compressor or indoor unit.
• Hissing or whistling noise: Can be caused by leaks in the refrigerant line, or an imperfect wall seal.
• Rattling or vibrating: Loose components, such as screws or bolts, or a loose housing frame.

How to Fix:

✔ Tighten loose parts: Check for loose screws, bolts, or any other components and tighten them.

✔ Inspect the housing: Make sure the unit sits securely in the frame to eliminate rattling or vibrating noises.

✔ Professional inspection: If unusual noises persist, discontinue using the heat pump until an HVAC tech has inspected the unit.

4. Short Cycling

Heat pumps are designed to operate in cycles, turning on and off as needed to maintain the desired temperature. Short cycling occurs when the system turns on and off too frequently. This can cause premature wear and tear, greatly shorten the pump’s lifespan, and increase your utility bills.

Possible Causes:

• Incorrect sizing: A heat pump that is too large for the space may short cycle as it struggles to maintain the programmed temperature.
• Thermostat issues: Incorrect thermostat settings or a malfunctioning thermostat can contribute to short cycling.
• Refrigerant problems: Low refrigerant levels may cause the system to cycle improperly due to reduced heat exchange performance.

How to Fix:

✔ Size confirmation: Consult with a professional HVAC contractor on whether the heat pump is appropriately sized for the space.

✔ Thermostat check: Calibrate the thermostat to ensure accurate temperature readings, or replace it if necessary.

✔ Refrigerant inspection: A professional should inspect the refrigerant levels to ensure the unit is performing to spec.

5. Inadequate Defrosting

Proper defrosting is crucial for heat pump operation, especially in colder climates. If the defrosting process is broken, it can lead to reduced performance and efficiency.

Possible Causes:

• Defrost control: A malfunctioning defrost system may result in inadequate defrosting.
• Sensor issue: Faulty or blocked outdoor temperature sensors can affect the defrost cycle by incorrectly reading the temperature.
• Refrigerant imbalance: Low refrigerant levels can affect the heat pump’s ability to defrost efficiently.

How to Fix:

✔ Check defrost controls: Test the defrost controls for proper functioning and replace any defective components.

✔ Sensor check: Calibrate the outdoor temperature sensor or replace it if it is malfunctioning.

✔ Professional inspection: Consult an HVAC tech to inspect refrigerant levels to ensure efficient defrosting.

Regular maintenance and prompt troubleshooting are essential for the optimal performance of heat pump systems. While some of the issues can be addressed through simple DIY solutions, more complex problems require a professional HVAC technician. 

By understanding these common heat pump issues and their remedies, we hope this allows you to take proactive measures to ensure your heat pump runs smoothly and efficiently for many years to come.