Why Is My Heat Pump Blowing Cold Air?

AC Blowing Hot/Warm Air What's Wrong? (6 Common Causes)
AC Blowing Hot/Warm Air What's Wrong? (6 Common Causes) from learnmetrics.com


As the winter season approaches, it can be quite frustrating to find that your heat pump is blowing cold air instead of providing the warmth you need. This issue can leave you feeling uncomfortable and desperate for a solution. In this article, we will explore the possible reasons why your heat pump might be blowing cold air and provide some tips on how to troubleshoot and resolve the problem.

1. Thermostat Settings

The first thing you should check when your heat pump is blowing cold air is the thermostat settings. Ensure that the thermostat is set to the desired temperature and the fan is set to auto. If the fan is set to “on,” it will continue to blow air even when the heat pump is not actively heating.

2. Outdoor Unit Obstructions

An obstructed outdoor unit can also cause your heat pump to blow cold air. Check for any debris, such as leaves or branches, obstructing the unit. Clear away any obstructions and ensure that the unit has sufficient airflow.

3. Air Filter

A clogged or dirty air filter can restrict airflow and prevent your heat pump from heating effectively. Check your air filter and replace it if it appears dirty or clogged. Regularly changing your air filter can help maintain the efficiency of your heat pump.

4. Refrigerant Levels

Inadequate refrigerant levels can cause your heat pump to blow cold air. Low refrigerant levels may indicate a leak in the system, which should be addressed by a professional HVAC technician. A technician can diagnose the issue, repair any leaks, and recharge the refrigerant to restore proper heating.

5. Defrost Cycle

If your heat pump is operating in cold weather, it may periodically enter a defrost cycle. During this cycle, the heat pump temporarily switches to cooling mode to melt any frost or ice buildup on the outdoor unit. This can cause the heat pump to blow cold air for a short period before resuming normal heating operation.

6. Mode Selection

Check that your heat pump is set to the correct mode. Heat pumps have both heating and cooling modes, and it’s possible that the wrong mode has been selected. Make sure the mode is set to heating to ensure warm air is being produced.

7. Faulty Reversing Valve

A malfunctioning reversing valve can cause the heat pump to blow cold air. The reversing valve is responsible for switching the heat pump between heating and cooling modes. If the valve is stuck or faulty, it may not be properly directing the refrigerant flow, resulting in cold air instead of warm air. Contact a professional technician to inspect and repair the reversing valve if necessary.

8. Power Supply

Ensure that your heat pump is receiving an adequate power supply. Check the circuit breaker to make sure it hasn’t tripped. If the breaker has tripped, reset it and observe if the heat pump starts to produce warm air again. If the breaker trips repeatedly, there may be an electrical issue that requires professional attention.

9. Outdoor Temperature

Extreme outdoor temperatures can affect the heating capacity of a heat pump. In very cold weather, heat pumps may struggle to extract enough heat from the air to provide the desired warmth. In such cases, it’s advisable to have a backup heating system or supplemental heat source, such as a furnace or electric heater, to ensure your comfort.

10. Professional Assistance

If you have checked all the above factors and your heat pump is still blowing cold air, it’s time to call in a professional HVAC technician. They have the expertise and tools to diagnose and resolve complex issues with your heat pump. Don’t hesitate to seek professional assistance to ensure your heat pump is functioning optimally.


Experiencing a heat pump blowing cold air can be frustrating, especially during the winter season. By checking the thermostat settings, clearing outdoor unit obstructions, maintaining the air filter, monitoring refrigerant levels, understanding defrost cycles, ensuring the correct mode selection, checking the reversing valve, verifying the power supply, considering outdoor temperature limitations, and seeking professional assistance when needed, you can troubleshoot and resolve the issue effectively. Remember, regular maintenance and professional inspections can help prevent future problems and keep your heat pump functioning efficiently.