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Why Is My Heat Pump Not Cooling AVS Tech Answers

Your heat pump not cooling is the last thing you want to deal with during the heat, especially if you reside in Arizona during the summer.

There are a variety of reasons your heat pump may not be cooling your home properly, and some of them have fairly easy (and cheap) fixes.

A few common reasons your heat pump may not be cooling your home include:

  • Wrong thermostat setting
  • Refrigerant levels are low
  • The outdoor unit is dirty or blocked
  • There are leaks in the ductwork


Below, we’ll go into more detail about each of these issues and their fixes, so you can get back to feeling cool and comfortable in your home.

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Reason #1: Wrong thermostat setting

This may sound obvious, but if your heat pump isn’t cooling your home properly, our first suggestion is to check your thermostat and make sure it’s set to AUTO and COOL.

Cool vs Heat setting thermostat 300 225 65

COOL probably seems obvious, but why set your thermostat to AUTO instead of ON?

When your thermostat is set to ON, it will continuously blow air into your home, regardless of whether that air has been cooled or not. When your thermostat is set to AUTO, it will only blow cool air into your home.

If you’re noticing that the air coming from your AC vents is not always cold or your home simply isn’t cooling down, start by checking your thermostat settings.

Reason #2: Low refrigerant levels

Your AC actually cools your home by removing the heat from your home’s air. Your system does this by stripping your home’s air of heat, and carrying that heat outside via refrigerant lines.

However, if refrigerant levels are low, your AC system will not be able to carry as much heat out of your home, which means your AC system will struggle to cool your home. If you notice that your heat pump is not cooling and it’s running longer than usual, this is likely your issue.

If your refrigerant levels are low, you will need a professional to repair your refrigerant lines and refill your refrigerant. Refrigerants can be harmful, so this is not a repair we’d suggest attempting on your own.

Reason #3: Dirty or blocked outdoor unit

As we mentioned above, your AC cools your home by removing heat from indoor air. It strips your home of heat via refrigerant and dumps this heat outside via the outdoor unit.

However, if your outdoor unit is dirty or blocked, your AC system will have trouble releasing that heat from the refrigerant to the outdoor air, keeping your home at a warmer temperature than desired.

dirty condenser

If your outdoor AC unit looks something like this, a dirty outdoor unit could be your issue.

To fix this, clear away any debris that is stuck to the outside of your outdoor or condenser unit.

You can also use a shop vac to lightly clean the condenser fins.

For more in-depth cleaning, you’ll want to hire a professional. Although this may seem like a simple task to take on yourself, cleaning your outdoor unit incorrectly could lead to larger issues (and more expensive repairs) down the road.

Reason #4: Leaks or holes in the ductwork

Your AC cools your home by pumping conditioned air into your home via ducts, which are normally located in unconditioned spaces like an attic or crawl space.

If there are holes in the ductwork or leaks between ducts, this cool air can escape into unconditioned parts of your home. Ultimately, this means the conditioned air that is meant to cool your home is leaking out, and your home isn’t reaching the temperature you’ve set for it.

Unfortunately, if you do have holes or leaks in your ductwork, you’ll need to have a professional assess the situation and repair or replace any damaged ductwork. This is not a fix you should attempt to complete on your own, as you could further damage your ductwork or injure yourself.