How to Build a DIY Pool Heater for Any Size Pool - Why All My Other Pool Heaters Failed!!!

I really appreciate the follow up video with the break down of what went wrong on previous builds. That's how we all learn!

I was a little concerned about the mixed reviews, but I used it last year and hooked it up again this year and it was great youtube.com/post/Ugkx-izdrK3eF-HMvjzeBOxToD6Fx-4ul… . I couldn't get my 10' Intex pool above 76 degrees the year prior and last year I got it to 90 and had to put ice in it. This worked so well! I have just 1 mat hooked up to a 1,000 GPH Intex pump and it makes a significant reduction in the flow rate coming back into the pool, but that is to be expected with how far the water has to travel through the mat.

For 20 years we had a large oval above ground pool in Michigan. We used 3 commercial pool heat panels 4x20 ft on a ground mounted platform. The design of the panels was such that you could easily run them in series but the dealer suggested not to do that as it increases the load on the pump and lowers the flow rate. So we used a custom manifold to connect the three panels in parallel. We also used a separate pump to run just the solar heater so we could run it whenever we wanted and it was 1/3 the electric use of the primary pump. I built a simple Arduino controller that ran the pump only when the pool was below our preferred temp and the solar panel was at least 5 degrees above that. In full sun the water coming back into the pool was about 10 degrees higher than the pool through a 1.5" pipe at full flow, so that's a lot of BTU! To prevent cycling I also set a minimum cycle time of 5 min either off or on though this rarely was an issue. This was a set it and forget it solution for the entire summer and the pool was always nearly the perfect temperature.

I don’t know much about water flow and heating but the constant learning and community feedback working towards the most efficient/cost effective system is so cool! The fun is in the problem solving, not the solved problem! Never give up! 🥳

This method of using the dowels is the way to go! Thanks for the video..

Nice video but a recommendation... I don't think you should be trying to throttle flow based on temperature. It's all about the BTUs going into the system from the sun. That doesn't change so it doesn't matter if you are flowing 1 gpm and getting 150 degree water or flowing 20 gpm and seeing a 2 degree temperature rise because the BTU heating into the pool is the same. The difference is in where you mention you keep the polycarbonate off the roof because it gets too hot. You are actually allowing BTUs to "escape" by doing this and thus not putting those BTUs into your pool. You'll be far far better off in this case to keep the poly ON but keeping flowrate HIGH to keep the temperature down so it doesn't melt your piping. Doing that will put more BTUs into your pool. Anyway, just wanted to point out that the temperature on your outlet pipe doesn't matter... it's the BTU input. :)

This is a great video. However the times have changed in favor of the products in today's given time. Instead of doing solar paneling and having to wait till the sun can generate enough heat to get hot water to the pool. I opted for a 8 gallon electric tankless water heater. I wanted the ability to have on demand hot water at well and not wait for the sun and what if overcasting was an issue. But after 1 hour of installation with a water transfer pump two hoses I now get 150° of water at will. I also bought a digital timer so that way The tankless water runs 15 minute intervals and turns off 1 to 2 minutes and restarts again. I could have went with solar and was about to do so but by the time I would have calculated all the pieces needed for an extra $100 I decided to splurge with the tankless water heater, it's just the options today you don't have to work as hard using solar. Not saying solar is not a good solution it is for those who get plenty of sun.

Here are a few suggestions for making your solar heater system better, safer and more efficient. #1 Get a water pump dedicated to supplying your solar heater system. A "hot water recirculating pump" would be ideally suited for this.This will also negate the need for any valve or valve adjustment between the inlet and outlet of your solar heater, and unburden your main pool pump from pushing water up to the solar heater. #2 Use a temperature controller to activate your solar water pump whenever the temperature in your solar panel is above 100 degrees. This will automate the fill and flow process and protect your solar panel from overheating, melting and from operating when cold. #3 Setup a manual override to force the solar pump on during testing. #4 Use solenoids to allow filling and draining of your solar heater. Empty when not used and freeze protection.(need separate drain) #5 Add an enable switch and temperature controller for your fill and drain solenoids, also with a manual override for testing. (note" #2 would be enabled by #5 if you use solenoids) I hope this gives you some food for thought and helps you to upgrade your system.

I was on a building job back in 91 in the UK and the owner had a pool with a black hose pipe going all around the edge, probably 10-20 times to heat the water. It was great to take a dip on a hot sunny day but one day we weren't told the pump had been switched of and the temp had got down about 10 degrees so we had a shock when we jumped in!🥶

Putting in a heating system myself. Bought a heater but the solar system looks like the way to go. Thanks for the tutorial and the comments from others is also a massive help.

As someone who has done these for pools myself, I recommend keeping your plumbing at 2 inch. Then restrict the 2 inch pipe on the roof down to your 3 heating coils, then back to 2 inch going back down to the original plumbing, this will help to make sure your pressure does not spike, it will also move the water much quicker through your system so it doesn't melt your system. And also you won't have to use a ball valve to force it. You can shut the ball valve off completely and the flow and pressure would stay the same. Also of you're going to keep the roof seal with the plexiglass, I recommend you find a way to vent it. That heat held in like that drives the air temp up to 250-300° in the summer time.

Perfect - binged watched your pool heater vids - thanks for going up and over the “ learning curves” so I can do it right the first Time. greatly appreciated. god bless you man

You don't need to restrict the flow my friend. The more water you flow through the system, the more kilowatts of heat you get out of the collector and into your pool. it doesn't matter if the returned water is not so warm, because the total amount of heat is greater due to the increased water flow. The only limitation is the amount of power you want to consume with your pump.

Lots of good info and learning from experience in the video and in the comments. I'd make the spirals with the send and return lines paired, with a U bend in the centre. Lines could enter/exit together or on opposite edges. This way the spiral can stay flat without overlaps. Slow flow is great if you want to make a cup of coffee, heat radiators for the house or do the washing up, but high flow within reason is best for getting energy out of the system. Of course, running at a high flow rate uses peak rate energy so a trade off is needed. A couple of solar panels could do this as it only needs to pump when the sun is up.

You clearly don't understand thermodynamics but decent build. Increase flow through heaters to increase heat into the pool. This will also keep the heaters cooler which will make the plastics happier. Also think about thermal expansion., Slowing the pipes to move as they heat up and get longer.

Thanks for the update

So, there are a few reasons your other attempts failed actually. The first is going to be water flow. I come from the PC liquid cooling space personally and this is something we pay attention to quite alot. You need more flow through the black tubing. Doing this will mean that the tubing can only get so hot at any given time but still give a great chance to let the water heat up. This is due to the fact that water will pull a ton of heat out of the tubing. The more flow the better. The second is already mentioned in another comment. Putting the plexiglass over the top will drive the temps way high. Which is good to some degree but partnered with the problem of not enough flow this will instantly start melting pipe. So instead you should have some sort of venting mechanism. It doesn't have to be much but just enough. If you even did something as simple as putting venting holes in the side of the case it would be enough. So first increase the flow through the tube, ideally all of your water flow through that tube for best results. Next, the venting. If you do both of these you won't have any issues. Think of this like the balloon with water in it. If you put water in a balloon and hold a lighter to it, it doesnt pop. Because the water is keeping the temperature under control.

spray flat black paint on the pipes where you hit it with temp gun , any shiny or reflective surface will give false readings as the beam from gun deflects and hits something near by

Great Vid, I appreciate all the attempts, as I've been doing similar things. One thing to keep in mind is that the goal is not to get the water as hot as possible, its to get as much heat into the pool. You slowed the flow several times to show increases temp, but that is also what's making your other attempts fail. Said another way, a small amount of super hot water is not better than a large amount of slightly hotter water. The thermal dynamics are the same in the main body of water. Increase your flow as much as possible to protect the heater. You won't gain anything by slowing it down. I've had several attempts fail with the "Sprinkler Hose" for too. It just isn't made for this kind of heat. Pex hose or garden hose allow much more flow, and have higher temp ratings if you have to try again.

Since you're more interested in the pool temperature and not the temperature of the water coming out the heater - you should have the flow as high as you can. This will give the best thermal transfer ability and heat the pool more.