DIY Pool Heater - $50 Solar Heater

Check out our $50 solar pool heater build we made for our super cheap $250 dollar DIY pool!

While the kids love swimming in our homemade pool, the water is a little chilly for the little ones. We set out to make a cheap and easy DIY solar pool heater that we could run off of the exiting pump. This particular design used about 400 feet of tubing and heats the water about 12 degrees through the run.

Build List
4 x 8 1/4 inch sheet - $10 (our was free scrap)
2 x 4 stud - $5 (we ripped one in half, buy a 1x2 if you don't have a table saw
Tubing - $40 - 500 foot role (we used about 400 feet)
screws and hose connections - $5 - 10

If you're planning on putting a plastic sheet on top, the price varies quite a bit. You could get away without that, or just a plastic wrap style.

#diy #pool #heater

[danratsnapnames]

FYI - i did this for an in ground pool. you dont even need it to be spooled nicely like this or anything.. just toss the black hose on your roof and have your pool water circulate through it.. wala.. you'll have a really heated pool in no time.. do it with the pool filter pump or with a different pump, it does not matter.. just noticed this was 2 years ago.. but if anyone else reads comments other than me, just know that it works pretty well for a large 6 foot deep inground pool in florida. and almost too well for a small jacoozy.

[Team]

I seriously thought Steve Buscemi started a DIY channel by hearing your voice! Love it!

[Tikolico]

I'm going to loop my pool water through my gaming computer, cool the rig, heat the pool, two birds with one stone!!.

[rronmar]

Someone brought this up earlier, but you really want to increase the flow and lower the outlet temp. The biggest factor in heat transfer is temperature difference. You have a 140F chamber and the cooler the tubes, the more heat they can absorb. If I recall your numbers i think you had 77F in and 89F out at the lower flow which you thought was about half the higher flow. Lets say that flow was 1 pound per minute. 1 BTU will heat 1# or water 1F, so that would be 12BTU/min or 750BTU/hr. You said the higher flow netted you about 87F, or 10F rise, but at double the flow(2#/min) that is 20BTU/min or 1200BTU/hr. You may have a lower temp at the higher flow, but you are actually capturing more energy because the lower coil temp makes the panel more efficient. Nicely done, most people neglect the clear cover, and that makes a significant difference in how well the work.

[ehRalph]

I made a round one of these about 20 years ago. It has been stored outside every winter and I’ve modified my design over the years. The first change was to make long straight runs looping at the ends like a racetrack to reduce resistance and the amount of bends. Then I went to a zig-zag design using male/female barbed fittings to reduce the system’s footprint and make it easier to drain out before winter. The original was 3/4” pipe and I added a few hundred feet of 1” pipe in the same zig-zag arrangement. This black pipe is super durable (you can walk on it), but I’m changing my design away from zig-zag and using tee fittings barb-female thread-barb to make the pipe run close and parallel and less pipe. If you have a retired clear solar blanket like I do, you can glaze over the solar panel to increase heat gain and prevent loss from wind and light rain. All this engineering is great, but as my dad once said “ to late smart” because I believe there a much easier and cheaper way to make a solar heater using a 2” heavy duty black roll-up Swimming Pool Backwash Hose - 50’ for $35 Amazon. Just lay the hose out or cut it into a couple parallel runs and glaze over it with clear plastic.

[carlosluna]

Very, very impressive. I really liked your heat-saving techniques (the black paper backing, using an enclosure to trap the heat, etc). Really cool and can't wait to try it. And just like any good teacher, you made it look so simple. Well done!

[angelamccourt]

We did this and it is AWESOME - thank you so much for the great idea!! We live in the SF bay area and the last couple years our pool has always been more on the "frigid" side. Within a few hours of setup and starting the heater we had 80 degree reading. It did cost cost a bit more than $50, but worth every penny 😀 Thanks again for the great idea!

[TomTom-vivp]

Looks great. You could also consider adding a thin layer of sand to what the coil pipes sit on, and then having two large mirrors on the ground angled at the sand to make the heat increase, like them solar power stations near Vegas maybe

[jtjvvlr]

I have a friend in the South of Spain and all of her hot water is heated via pipes on the roof. Like the idea of the sun heating the water for free.

[ginadelsasso]

Thank you. I will share this with a friend. I think it would make a great shade on top of her deck for her pool.

[alucard]

You know this was a good initial concept a few years back. But with what today's products are and options I decided to opt for a tankless 8 gallon electric water heater and water transfer pump. Keep in mind the cost difference was only $100 more to go fully electric instead of solar materials needed for the project. The interesting thing is is I now get up to 150° on demand whenever needed however I still have yet to see what the electric bill is. I had to go with the electric heater just because I never know what the weather is going to be and overcasting scenarios. I like the convenience of getting hot water on demand. Me watching these videos allowed me to uncover my new 2.0 electric water heater process and after an hour of installation it works flawlessly. I'm not saying it's for everybody but do your own research.

[craigzilla]

Just breezing over the fact that you also made your own pool.. lol. You're a talented guy!

[markwisner]

I built my own version. I did some thing differently that make mine easier to deal with. I live in NC. All we need is to get the pool up to temp when we open it in April and allow us to stretch our season a couple of weeks in the fall. We do use a solar cover to help keep any temperature gain through the night. We don't want to look at the heaters all year so we need them to be portable or more portable than your version.
1) I made two 4'x4' heaters. Each heater has ~200 ft of 1/2" irrigation tubing. A 4x8 panel is way too cumbersome for me to move around by myself.
2) I added two non-swivel casters to one side.
3) I added a handle on each of the other sides.
I can roll them away when I want to store them. The coils hold several gallons of water at 8lbs per gallon. They are pretty heavy.

I run a 500 gallon/hr pump and get a 10 to 12 degree temp increase. It may not sound like that but I am doing a pretty good flow rate. My pool is around 10K gallons. I am able to increase the pool temp 15 to 20 degrees in little over a week, depending on sun and outside temp. If the tubing feels warm then you are not absorbing as much heat as you could.

In the winter, it does go below freezing. We usually close our pool at the end of Oct. and reopen it the first week in April. If any water is left in the tubing, it could freeze and split the tubing. You could take an air compressor, get a garden hose air compressor connection at any RV store, and blow out the lines. But if you don't get all the water out, you could have a problem. I plan on pouring a couple of gallons of RV/Marine food grade antifreeze into a bucket with my pump and pumping it through the solar heaters. I will flush the antifreeze out with water in the spring.

[yogidemis]

I thought about doing this method of a pool heater but I was thinking about doing the fire heater, pumping water from the pool thru a steel tube slowly thru a fireplace and back into the pool. Be kinda cool to have a fire five feet from the pool while heating up the water. Plus the fire water heater would work on cloudy days as well.

[gamenuts]

I grew up on a similar system :) My grandpa put the hose on the roof, that was tiled with ceramic tiles. We had free warm water all summer 😎

[rupe]

To clarify some of what others have said, there's a little science behind heat transfer and it may work in your favor. If the water in your coils is too hot it will shorten the life of the poly pipe, and also could be uncomfortable to anyone near the discharge. The most heat transfer will happen with the least loss with only a few degrees temp rise. This is mostly because the rise will slow down as it reaches ambient temp. IOW, something between 2-5 degrees rise (from in to out) is a good target because the rising pool temp will slowly raise the inlet temp anyway. The reality is most people need to increase their flow rate. The goal is to have a continued but slow rise. In tech terms that's called a differential. The other tip I will throw in is that on order to make an appreciable rise the sq ft of the solar must be about 50% of the pool surface sq ft.... or higher. Most people use a small panel then wonder why they don't see a difference. The reason is the sun only shines so long but the pool cools off during the other 18 hours of the day. Keeping the pool covered can also gain you an extra 5-10 degrees by slowing evaporative cooling. Some people say a pool cover is too expensive, but that's cheap compared to heating a pool by conventional means.

[erikrempel]

"Do it Wrong Yourself" that was enough to get my sub.. Irony, I love it. I appreciate the no-nonsense video, top notch work. Backyard builder approved.

[pwrgreg]

I used this idea to do a less-expensive (although less effective) version: running the tubing along our in-ground pool fence. The fence is about 60 feet on the long side. It took four-and-a-half trips around to get all 500 feet of tubing unwound & installed. I put the spool on a sawhorse so was easy to counteract the half-turn at the ends, and any other twists that arose. To save money, I used old 10baseT ethernet wire cut to length (solid wire better than stranded), but zip ties etc. will work. The water temp went from 65 to 80 in less than two weeks. In full sun, it comes out about five degrees warmer than it goes in (max temp so far here in middle Georgia has been about 80). One-third hp sump pump on a timer powers it, but a thermal switch would be better, set to about 80 degrees. When it gets warm enough, the tubing (inlet fed by a short feeder hose) will be folded back up along the fence out of the way. Outlet end is about six feet long with an elbow so it hooks onto the edge of the pool, and folds away neatly. I'll ad a pic if I can find out how to do so.

[phoglite]

Awesome build! Decreasing flow rate may increase the delta T but it won’t speed up heating the pool. Consider mixing a drop of boiling hot water to a gallon of ice water vs adding a half gallon of Luke warm water to half gallon of ice water. In both cases you have about a gallon but the Luke warm / ice water mixture will be much warmer overall. And in this case it probably makes zero difference but you might start to see higher losses to air around the panel as its temp delta to air increases, increasing convective heat transfer to the surrounding air.

[petec]

Not a bad build at all. Back in the early 70's I built a solar heater for my mother. She had a patio with a sink and cold water only. One day she said she wished she had a source of hot water. So I went to the local hardware store and bought five 8' lengths of 4" ABS pipes and some fittings. With short tubes between elbows, all in all it was about 393 inches in length. 4"Ø x Pi x 393" = 4, 938.6 cu. in. of water. Divide that by 231 (cu. in. per gallon) comes to a water capacity of abut 21.4 gallons of water sitting on an asphalt shingle roof (slope 1:48"). Not a lot of hot water, but the Southern California sun would heat that water to pretty darn hot. Mom was pleased.

At the top of the two lengths I drilled quarter inch holes tapped with NPT 1/4" thread and installed 1/4" plugs. Their purpose was so the air could be removed and effectively make the system nearly full of water. Darn thing worked great.

How many gallons of water in your pipe? You said bout 400 feet of 1/2" piping. @400 feet of 1/2" piping that's about 4.1 gallons of water. With a 1" pipe you would have four times the volume for the same length. Like I said, this was back in the early 70's so I didn't do any temperature testing. But the water basically sat in the sun all day, every day unless mom used the hot water outside.

One thing you didn't mention was water flow rate, how many gallons per hour. With that information you can calculate the thermal gain versus the size of the pool, heat loss to atmosphere at the surface as well as how long it takes to heat the total volume of the pool. All in all, it's not a bad build. I wish I knew how much thermal gain I got out of my system. One thing I DID learn the hard way was to put an over-temp / over-pressure relief valve on the system. I blew out a pipe. Had to rebuild a small section and installed the safety pressure relief valve. In the end it was a great system.