Why Is My Heat Pump Not Blowing Hot Air? A San Marcos Tech Explains


When you’re expecting heated air to come from your vents but are getting lukewarm or even cold air from your heat pump, it can be frustrating.

Don’t worry, though—we’ll help you troubleshoot this common problem.

If your heat pump is not blowing hot air, it means 1 of 2 things:

  • Your body is tricking you
  • Your heat pump has one of these issues:
    • Low refrigerant charge
    • Bad reversing valve
    • Auxiliary heat is malfunctioning
    • Problem with the outdoor unit

We’ll go into more detail about all of this below.

Need a heat pump repair? Let us repair it for you!

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If your heat pump is reaching your set temperature but you feel cold air...

Here’s why: Heat pumps blow air that’s around 85° to 93° F. However, since our body temperature is around 98.6°, this air can sometimes feel cold to us.

Even though this air feels cold to us, it’s still heating your home.

So, how do you know if this is your issue?

If you see that your indoor temperature matches the temperature you set on your thermostat, your heat pump is working fine and there’s nothing to worry about.

If your heat pump is NOT reaching your set temperature…

… then your heat pump has one of the following issues:

  • Low refrigerant charge
  • Bad reversing valve
  • Auxiliary heat is malfunctioning
  • Problem with the outdoor unit

Before we dive into each of these issues in more detail, we’ll start by saying all of these issues require professional assistance. If you want to skip the explanations and just want a heat pump repair ASAP, contact a professional for help.

Issue #1: Low refrigerant charge

Your heat pump warms your home by absorbing heat in the outdoor air and bringing it inside. The substance that facilitates this process is called refrigerant.

If your heat pump system is low on refrigerant, it will struggle to heat your home, which could explain why you’re not feeling hot air coming from the vents.

Solution: A professional can check your heat pump’s refrigerant levels. If your system has low refrigerant, it usually means you have a leak that needs to be repaired. The professional will identify the leak and recommend repair options. Once the leak is fixed, the professional will add refrigerant to your system.

Issue #2: Bad reversing valve

In addition to heating your home, a heat pump also functions as a regular AC during the summer months.

Learn more: How Does a Heat Pump Work in Cold Weather?

The device that controls the heating and cooling functions of your heat pump is called the reversing valve. The reversing valve controls the flow of refrigerant based on the heating/cooling demand.

Sometimes these valves can malfunction, which could explain why you’re not feeling hot air when you’re supposed to.

Solution: A professional can inspect your system to see if your reversing valve is working properly. If it is not, they can replace it for you.

Issue #3: Auxiliary heat is malfunctioning

Ever notice the “AUX” heat mode on your thermostat?

AUX heat refers to your heat pump’s auxiliary (backup) heat source. Auxiliary heat kicks in when your heat pump can’t produce enough heat to warm your home by itself.

Learn more: Why Is My Heat Pump Running on AUX Heat Mode?

If you’re not feeling hot air coming from your vents, the backup heat source could be malfunctioning.

Solution: A professional will inspect your AUX heat source (whether it’s electric resistance heating or a gas furnace) to see if that is the source of the problem. If your AUX heat source is down, they can recommend options to repair it.

Issue #4: Problem with the outdoor unit

The outdoor unit of your heat pump is the part of your system that absorbs warm air and brings it inside to heat your home.

If there is an issue with the outdoor unit, then your heat pump can’t absorb any warm air, and you’ll feel cooler air coming from your vents as a result.

The most common issues with the outdoor unit include:

  • Broken or dirty coils
  • No power going to the outdoor unit
  • Frost or ice is covering the outdoor unit

Solution: A professional can check to see if any issues are preventing your outdoor unit from doing its job.

Need a heat pump repair? Let a trusted Texas HVAC pro help!

Schedule appointment today

We offer same-day service! Our technicians are standing by to help.

For more information about what to expect when you hire us, visit our heat pump repair page.