Fixing An Air Conditioner Unit That Won’t Heat

An Air Conditioner in a white living room

Is your Air Conditioner unit’s heat pump refusing to heat, and it’s driving you crazy?

You’re not alone! In fact, this is something that affects thousands of people on a daily basis all over the world.

I know that having issues with an appliance designed for convenience is no fun. Especially if it’s freezing inside your home, and you’re in desperate need of some heat.

But don’t worry, you came to the right place for answers. Below, you’ll find a list of several things you can try to get everything back to normal and stop feeling like you’re living inside a freezer.

When your Air Conditioner unit won’t heat, you can try checking your settings, cleaning the air filters, and looking out for refrigerant leaks. If that fails, you can also take a closer look at the appliance’s fans and see if you spot any damage.

Keep reading to end the Ice Age!

#1 Check Your Settings

First, let’s cover something extremely obvious, yet common among Air Conditioner owners.

I know you might be thinking there’s no way on Earth that you entered your desired settings incorrectly, but you’d be surprised by how often this happens.

A person adjusting the settings of an Air Conditioner
It’s the little things we tend to overlook more often

When something goes wrong with our appliances, we tend to look at the most complex possibilities first, and only consider the obvious as a last resort. However, this is not the right way to go about things. Remember, troubleshooting is all about going from the closest possible explanation to the most farfetched factors.

Solution: Take a closer look at your remote’s settings, or check your thermostat’s display. Make sure you haven’t accidentally set the appliance to cool and go from there. Provided you’re 100% sure that you dialed everything in correctly, please keep reading for some useful fixes.

#2 Clean the Air Filters

Now that we’ve ruled out user error, let’s talk about maintenance. I know this is a tedious thing to do, and most appliance owners tend to skip it altogether. But what if I told you that failing to clean your Air Conditioner’s filters could not only explain this situation but also increase power draw and reduce the unit’s lifespan?

A person cleaning an Air Conditioner's dirty air filters
Letting your appliance’s filters get too dirty can cost you hundreds of dollars every year

There’s a good chance that, if you haven’t cleaned your filters in a while, airflow is being highly affected, thus leaving you stuck fixing an heat pump that won’t heat.

Solution: To clean your air filters, please follow the simple steps below:

  1. If possible, cut the power supply to the room you’ll be working on.
  2. Turn the Air Conditioning unit off.
  3. Most models can be opened simply by lifting the front panel upwards (if your model has screws, carefully remove them to lift the front tab).
  4. You’ll immediately see the unit’s filters.
  5. Carefully remove them and place them somewhere to clean.
  6. Use a vacuum to delicately remove any debris and dust buildup from the filters. You can also wash them gently in the sink with water.
  7. Repeat the process for all intake units in your home.

Ideally, you’ll want to do this at least twice per year, but if you live in an area with a lot of dust or pollen, you might want to increase the cleaning frequency.

#3 Look Out for Refrigerant Leaks

You’re probably wondering what refrigerant has to do with heating, and I don’t blame you. After all, it sounds very similar to “refrigerator”, so it must be exclusively related to cooling, right?

Well… not quite.

In fact, refrigerant leaks could easily explain why you’re stuck trying to fix an Air Conditioner’s heat pump that won’t heat.

You see, this liquid is responsible for about 60% of your appliance’s functionality, as it works as the “vehicle” for heat dissipation/preservation.

When there are any leaks present in your Air Conditioner unit, there’s not enough refrigerant to transport hot/cold air through the evaporator/condenser coils, thus creating a world of trouble.

Solution: Spotting refrigerant leak can be a bit challenging, and it’s almost always best left to professionals. Identifying a leak is challenging enough, let alone replacing the refrigerant.

#4 Inspect the Appliance’s Fans

Lastly, let’s make sure that the fan on your appliance is working normally.

The fan is located on the external unit in your backyard or designated area. Heat pumps work by pulling the heat out of the outside air, compressing it with the compressor and sending refrigerant (now a hot, high pressure vapor) to the indoor coil where a blower sends the cool air from your house through the coil where jt picks up the heat.

Something that wouldn’t be possible without fans.

A mini split air conditioner with a remote and an external blower unit
Air Conditioner fans are durable, but not eternal

More often than not, Air Conditioner fans and their motors are certified to last for a very long time. However, certain conditions, including power surges, incorrect operation or component overworking can sometimes break them down.

This could explain why you’re stuck fixing an Air Conditioner’s heat pump that won’t heat, or that can’t keep up with your cooling needs.

Solution: Replacing your fan motor might sound challenging, but it’s actually really simple. Here’s what you have to do:

  1. Get a replacement fan and motor either from your manufacturer or a nearby hardware store. To find the right one, check the part’s model number on the part itself and Google search for price estimations and availability.
  2. Locate the unit outside your home and see if the fan blades are spinning normally. If not, cut off the power supply to the machine, as this normally means there’s something wrong with the motor, and you’ll need to get hands-on.
  3. Carefully remove the screws holding the top grid in place to expose the fan.
  4. Follow the cable going from the fan to the inside of the appliance and remove any external panels to expose where the cables are going.
  5. Once you’ve located the fan cable hub, disconnect every cable, so you can remove the fan and the motor freely.
  6. Once you have a new fan and motor, carefully reconnect the part to the cable hub you had previously worked on and reassemble the unit.
  7. Restore power to the appliance and see if the fan now works as it should.

Disclaimer: don’t move too quickly on this, as when in heat mode the unit may be in defrost mode which operates with the fan turned off while the compressor is still on. Keep checking to see if the fan’s running correctly a good few times before deciding to replace it.


When you’re stuck fixing an air conditioner with a heat pump that isn’t heating, convenience can go out the window, leaving only frustration.

Luckily, as I hope this piece has helped you see, in most cases, addressing the most common causes behind this situation is very easy and quick. More often than not, simple actions, like checking your fan motor, and cleaning the air filters regularly, should do the trick.

Thank you very much for sticking with me all the way to the end. If this article proved useful and piqued your interest, you’ll be glad to know that there are tons of other resources to learn from below!

Have a great week.

— Craig.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more