Amazing DIY Pool Heater for under $150.00

DIY Pool Heater

Summer is here! Today, I’m going to show you our DIY Pool Heater under $150.00. It’s sure to keep you warm and swimming all summer long.

Maybe you are one of the many families who rushed to get a new above ground pool this year?

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I scoured the internet and Youtube for ideas on how to make an inexpensive heater for our above ground pool, and I have compiled my method and tips here.

How the pool heater works

It’s important to understand the mechanics in place before you start to build your system. In short, you will place your submersible pump in the pool. The output on the pump will be connected to your garden hose. The irrigation hose becomes heater coils which you will mount on the plywood.

Your heater coils should be placed for the maximum amount of sunlight. As the water travels through the heater coils, the sun warms the water in the coil. The longer the water travels in the coils the warmer it will get. I would recommend having at least 2 coils to notice a difference in water temperature.

The water will then be returned to your pool through the opposite end of your irrigation tubing.

Preparing for your heater

If you haven’t chosen your pool location yet, I would recommend picking the area of your yard that receives the most sunlight throughout the day.

During the first year, we had our pool, I made the mistake of choosing an area that was shaded in the afternoon. This meant that the water had more time to cool than it had time to warm. As well, we had lots of debris from trees and other yuk find our way to the pool.

Next, you need to know where to place the heater coils for the maximum amount of sunlight. A roof is optimum or you may want to simply line the heater coils near your pool. For aesthetics and safety, I chose to put ours on top of our aluminum screen room.

You will then want to mentally map out a plan of action where to place your hose and irrigation tubing. This picture is an overall view of my solar system.

Keep in mind that the pump only needs to be in the pool when it’s running. So, I left quite a bit of slack on the hose (green) going to the roof. When the pump was not in use, I would simply tuck it in a Rubbermaid tote near the garage door. This also helps keep the hose out of the way of daily activities.

Once you have a plan of action, you can start on the process of making your coils.

Making your heater coils

Start by making some guide holes in your plywood. I made the hole just big enough to slide the cable tie through. So you may have to practice to find the right size drill bit based on your zip ties. I drilled the holes approximately 1 ½ inches apart in a vertical column.

Next, paint your plywood panels black. It doesn’t really matter if you use spray paint, the black paint will help with the absorption of the sunlight.

If you chose to get the 500’ irrigation tubing, my recommendation is to get help from a friend! Walk in different directions to spread out the tubing to ensure there is no knotting or kicks.

Since you are going to attach a hose to one end of the tubing, leave a length of tubing free as you attach the first piece to your plywood. The next picture shows the beginning of the process. The tube on the top is the piece that will attach to my garden hose. Once the first cable tie was placed, I then tightened the circle formed and tightened the cable tie a bit more.

This is a total process! It will take time and some patience as you will need to avoid that inlet tubing that will connect to your hose. To make it a bit easier, I inserted plenty of cable ties in the pre-drilled holes so that I could keep attaching the tubing as I wrapped it into place.

I found that I could fit 2 tubes per 1 cable tie. As I worked, I stopped every so often to drill another hole in the plywood where the tubing seemed to need reinforcement. You may also want to use a cable tie without drilling the holes to keep your coil as flat as possible.

Here you can see the almost finished product. After getting all the tubing I could fit onto the plywood panel, I left enough additional tubing to connect to the next heater coil panel. Then, I repeated this process for an additional panel.

Make sure that you have enough irrigation tubing left over to use as your output hose. This will go from your last panel to your pool.

Once the coils were in place, I placed the panels on our aluminum roof. Since the roof has channels, I did not worry about using any type of frame to hold the panels up as runoff and debris would still find its way under the coil heater panel.

I was concerned that moving the panel might loosen some of the coils so I waited until they were permanently placed to tighten all the ties one final time and clip them off.

Connecting your Pool Heater

The next step in this process is going to be connecting everything.

Each home (and pool location) is going to be different. So, I can only provide you with the basic framework as to how I completed our pool heater.

I started by placing the heater coil panels in their permanent location. Since I used 2 coils, I connected them with 1/2” barbed drip irrigation coupling.

Then, I worked backward to the pool. You will need a barbed coupling attached to the intake of the first coil and connect a long run of irrigation tubing to the pool. The irrigation tube must be long enough to reach the bottom of the pool with a little slack for when you remove your submersible pump.

Next, you will attach your submersible pump to the irrigation tubing with 1/2” irrigation to Garden Hose adapter. The pump I purchased from Amazon had what the manufacturer called a “multi-fitting elbow”. In other words, the outflow was elbow shape (towards the bottom of the pump) and could fit 3 different sizes of couplings. The garden hose adapter fits perfectly onto the outflow elbow.

Next, simply place your pump inside the pool making sure that it is on solid ground. You do not want the pump floating about in your pool.

I also wanted to be able to easily remove the pump so I tied a piece of rope to the handle on the top of the pump which I could then tie only the pool frame with a slip knot. Without the rope, I would have to climb into the pool each time to retrieve the pump.

My submersible pump also came with an automatic float switch. When the pool was full, the switch did a fairly good job of floating and keeping the pump running. However, I also tied a piece of rope onto the float switch to make it easier to remove and manage when the pump was on.

Next, you will place another barbed coupling on the heater coil irrigation tubing, and you will couple it to more irrigation tubing that you will bring back to your pool. I used a left-over cable tie to attach the output hose to the pool.

I was also a bit concerned that it would be easy for the tubing to slide out of the cable tie, so I attached a hose adapter on this end as well. This is not necessary but an added reassurance that you won’t be spraying water everywhere other than your pool.

Remember one end is pulling water from your pool and attaching to the pump. So, it’s the other end that will return the warmed water to your pool.

Testing out your heater

The final step, of course, is to plug in that submersible pump and watch the magic happen!

I recommend you start at the pump looking for excessive leaks. If your seal isn’t tight on the garden adapter attached to the outflow, you may get a lot of bubbling and spray in the pool. Although our spray was contained in the pool, I worry that the loss of pressure could make the motor go bad more quickly.

Continue on the entire path of the irrigation tubing up to the coils. Make sure to look for leaks around your couplings. As well, look for areas of the tubing that may have become kinked in the coiling process as this will deter the water flow.

Once you’ve examined the coils, check for any leaks along the tubing coming back to the pool.

Finally, make sure that your coil is in a firm location inside your pool. I had just enough slack that I could pull the coil out of the swimming area when not in use and fit it under the solar cover when it was in use.

Final Tips

The weather will play a huge role in your DIY pool heater results! After all the time, money, and effort I invested, our first test was not very impressive. I tested the water temperature inside the pool, and then, tested the water temperature coming from the heater coil into the pool and only had a change of about 2 degrees. Of course, it was a cool cloudy day.

The next day I started up the heater was hugely successful! The water temperature inside the pool was about 66 degrees whereas the water coming from the heater coil into the pool was a whopping 107 degrees!

Since the output water temperature could be so high, I made a rule that the pump was only to be run before swimming and not during. I didn’t want a child thinking it was a fountain to play in and get burnt by the scolding water.

When not in use, I simply removed our submersible pump and placed it in a plastic tote near the house so that it was entirely out of the path of the pool. I didn’t want any children tripping over extra hoses or cords.

How long to run the pump is a personal preference. If I knew we would be swimming later in the day, I would try to run the pump for 1-2 hours around 12 pm- 2 pm when the sun is almost directly overhead. This may differ depending on your location and climate.

Now if you want some massive heating power and don’t mind spending a bit more, you can construct an enclosed box for your coils. For this option, you might want to invest in a high heat (grill) paint. To enclose the coils, you could use pressure-treated plywood for the backing and pressure-treated wood for the sides (even a 1” x 2” would work). You would need to use a polycarbonate or acrylic sheet as the cover so that the sun could still enter the box. This could get costly but could be well worth the extra effort.

I surely hope you enjoy making and using your DIY pool heater. It’s the perfect inexpensive solution for any above ground pool.

Please let me know if you have any tips you’d like to share with others here, and I certainly hope you have a great summer!