Have you ever been outside when your AC unit kicks on? If you have, then you’ve noticed all the heat that comes out of the unit when its fan is blowing. That heat is a side effect of cooling your home. Right now, all of it is being wasted. Normally, this isn’t a bad thing. You want the cool air from the unit, not the hot air, right? Most of the time, that’s true.

But that heat currently being dumped outside where it isn’t needed can be used to heat your pool. Now, both your home and your pool water can be at the perfect temperature, all thanks to a device you already own and a relatively inexpensive helper device called a heat exchanger. This device uses the generated heat from your AC unit that’s currently going unused and redirects it to heat your pool water. In this post, we’ll tell you how the technology works and how to install it.

Why Does Heating a Pool With AC Make Sense?

The start of pool season usually comes with the family excited to jump into the pool after you’ve de-winterized it, cleaned it, and killed any algae that may have made its way into the pool during the offseason. But too often, that joy is dampened when you hop into the pool and discover that the water is freezing even though the outside temperature is hot. Heating the pool eliminates that shock.

There are other practical reasons to use your AC as a pool heating method. The first is that heating the pool with your AC is completely free. After the cost of installing the device, it relies exclusively on the heat that was previously going to waste. Your pool is now heated for the same cost you’re already spending to cool your home.

Even better, your AC will run more efficiently with a heat exchanger. The hot refrigerant has to be cooled down somehow; that’s why the hot air is coming out of the unit in the first place. Cooling it with the air isn’t as efficient as running it through cold water. That’s why only small gas engines rely on air cooling, with the larger ones using a liquid cooling system.

As long as you plan on staying in the home for a few years after installing the system, the cost of installation ends up paying for itself through free pool heating and more efficient home cooling.

What Materials Do You Need On Hand?

Before you can get started on the project, you need to make sure that you have the proper equipment ready for the job. Because some of the processes will involve dealing with refrigerant lines and electricity, ensure that you either have the proper licenses and qualifications to perform these tasks or bring on someone who does to help. Below is a list of items you’ll need:

  • Heat exchanger – This is the unit that actually removes the heat from the AC and transfers it to the pool. It will look like a canister with two pipes coming out of it; one for input and one for output.
  • PVC pipe – You’ll need to measure enough PVC pipe to connect the pool pump and heat exchanger together. Be sure to include any corner pieces you need to make the connections. Additionally, you’ll need a T-connector to install the heat exchanger’s temperature sensor into. 
  • PVC saw – This is needed to cut PVC from your pool’s current plumbing to allow the heat exchanger to be added in and cut the new PVC to length.
  • PVC cleaner and glue – PVC pipe is cleaned and glued together to make the connections permanent. These two supplies are often sold in pairs.
  • Refrigerant line cutter – The AC line will also need to be cut in order to add the routing that runs it through the heat exchanger.
  • Refrigerant line – You’ll need enough refrigerant line to connect your heat exchanger to the current lines going to and from the AC unit.
  • Refrigerant recovery equipment – Before the refrigerant line can be safely cut, all the refrigerant must be removed from the system. 
  • Brazing equipment – Brazing equipment is used to permanently attach the new refrigerant line to the existing line.

8 Steps to Heating Your Pool With AC

Installation of a heat exchange into a pool pump system can be accomplished in eight steps. Disclaimer: many of the steps require advanced knowledge of the topic at hand and will require a professional to help out.

1. Cut Pipe From the Pool Pump

Make your way over to your pool pump and examine its connections. There will be a pipe that runs water from the pump to the pool. You’ll need to cut out a section of that pipe to make room for the heat exchanger to be added in. Before you make any cuts, shut off the power to the pump. Failure to do so can result in damage to your health or pool equipment. 

With the power to the pool pump safely shut off, measure how much you’ll need to cut to reroute the connections to the heat exchanger’s input and output pipes, and use the PVC saw to make the cuts. 

2. Fit T-Connector With a Heat Sensor

As you’re measuring the line going to the input section of the heat exchanger, make room for a T-connector. Inside the T-connector will be a heat sensor that determines whether the water needs to be heated by the exchanger or if it’s already hot enough. Dry fit the T-connector into place and install the heat sensor into it.

3. Fit Input to the Heat Exchanger

Now, finish making the cuts and connections required to connect the PVC pipe from the T-connector to the input portion of the heat exchanger. At this stage, you’re simply dry-fitting the connections to ensure that all of the cuts were made properly and that everything will line up as it’s supposed to. 

4. Fit Output From the Heat Exchanger

Next, repeat the process on the other side of the heat exchanger. The output portion of the exchanger should be taking the water towards the pool. This side of the heat exchanger doesn’t need a special T-connector or a heat sensor because the water will already be heated at this point. Simply dry fit the connections in preparation to finalize the PVC installation.

With all of the connections test-fitted and verified, it’s time to pull them apart and apply the glue to them. First, apply cleaner to the PVC to get it ready to accept the glue. Then, apply the glue, piece by piece, and begin putting together the final assembly. 

5. Remove the Refrigerant from AC

Now it’s time to move on to the AC side of the project. Just like with the pool pump, we’ll be connecting the heat exchanger to the existing AC refrigerant lines. Before that can be done, all the refrigerant must be removed from the AC unit. This step should be performed by someone who is licensed to work with refrigerant, as it can be dangerous both to you and to the environment. 

6. Fit Refrigerant Lines from AC to the Heat Exchanger

Figure out where you’ll be making the cuts to the refrigerant line so that it can be rerouted to the heat exchanger and back. After ensuring that the AC is turned off and the refrigerant has been removed, cut out the required section of the refrigerant line. Cut the new line to length and bend it as necessary to make the connections between the AC unit and the heat exchanger. 

When you’re sure that the refrigerant line is properly fitted, use your brazing equipment to make the connections permanent. 

7. Recharge the Refrigerant

With everything connected, it’s almost time to get the system up and running and test it. First, the refrigerant must be returned to the AC. Have a qualified technician recharge the AC system so it’s once again ready to cool the home and prepared to take on its new role as a heater for your pool. 

8. Install the Controller

If your heat exchanger came with a controller, now is the time to install it. These are generally mounted onto the wall of the home, somewhere near where the pool controller is mounted. The device then needs to be wired into the home’s electrical system and to the heat exchanger system. Be sure to shut off the main breaker before attempting this and let a professional electrician handle anything you aren’t qualified to do. 


Even though some of the steps require hiring a professional to help out, the fact that your pool is heated for free after the initial installation – and your AC benefits from an efficiency boost – makes heating your pool with AC a solid option for all home and pool owners. Even with the initial costs, you’ll save money over less efficient ways of heating your pool. 

ProTuff Products carries all the supplies you need to keep your pool running in tip-top shape and with maximum efficiency. For more information on how to save on pool costs, tips for pool maintenance like what to do when it rains, and why ProTuff Products’ lifetime replacement guarantee is the best deal on the market, visit our website today. 

Disclaimer: Pool ownership and maintenance is very complicated, and we know every situation is unique. While we’ve done our best to cover the best practices here, we encourage you to reach out to ProTuff directly at info@protuffproducts.com with any specific questions you may have.

Why Does Using AC to Heat the Pool Make Sense?
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