Thoughts on this method to heat my pool?

So, I have an intex easy-set 12' pool. We have finally leveled the ground and re-filled it and it works great. I live in Texas the swim season is pretty long already. I have this all rigged up with a bungee cord tether so I can swim in place for exercise. I dug out the center to give me another foot depth where I needed it. I also have a solar cover and the entire thing is covered by an elevated parachute tent for shade/wind block. (Also modesty). For now the water warms up significantly enough by about 10 am without much heat loss at night. I have thought long an hard and this is what I have come up with to heat it during the colder months. I can build a typical solar collector with hoses and hook it to either my saltwater sand pool pump or the cheapy pool pump it came with (which would be better?) then put it on top of a metal roof piece in the yard slightly elevated from rain water, then attach radiant floor heating mats underneath it. I am hoping this would provide a boost of heat on less sunny days or when it is significantly cold, like December. With a much cheaper energy bill. I am guessing I will need to insulate the heating things a bit or something. Feel free to suggest anything. I am just kinda in plan mode atm.

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HidiousTak (author) 1 year ago

Because of tropical depression Bill, pounding us with rain today I had to drain about 7 inches out of my pool. I realized the drain pipe perfectly fits a bit of hose I had laying around. The water ran out of that thing pretty quickly since it is at the bottom of the pool and has a lot of pressure on it. I am considering attempting getting a thermosiphon going with my solar heater. It would go down hill about six inches then heat up in the hose and have to come out almost 4 feet up. Idk if there is enough pressure to push it that far maybe that little solar powered pump would be enough to boost a solar thermosiphon.. Gonna play with seeing if there is enough pressure to return it to the pool.

RobT50 HidiousTak10 months ago

Been a while since this post, but how did this option work? I too am looking for a quick, easy, and cheap way to heat up my pool!

rickharris1 year ago

OK it's ho tfor a lot of the year so solar will be your cheapest option.

Even black plastic pipe will be enough to make a difference, under double glazed glass and a bit of insulation and you will get serious heat. It will need some way to pump the water through the pipe.

HidiousTak (author)  rickharris1 year ago

Thanks for helping me think through this. Bear with me on this comment I just typed it out and then my browser crashed and I lost it.


I love this concept but I am assuming 42 gal an hour will not heat a 1800 gal pool very effectively. Or the water will be extremely hot by the time it gets to the pool. If the pump can even pump pool water.

I do have a 530 gal per hour pump that is not being utilized, I might be able to figure out hooking a solar panel to that to run it only when the sun is out. (Hooked to the solar heater)

My actual pool filter pump is 1600 gal per hour (overkill but it was a craigslist deal)

I am unable to figure out if my situation (non insulated pool) will benefit from a faster or slower pump for heating. There doesn't seem to be much info on if faster/slower or what size of heater based on the size of the pool, or how much heat is needed. I am assuming the slower the water moves the hotter it will be, but adding it to the cool pool water that would heat it very slowly if at all since there's no wall insulation. So faster might be able to slowly increase the temp incrementally, but it would need to be a large enough heater to offset the pool cooling caused by the air temperature. I wish I could find the mathematical breakdowns of what is most effective/ cost effective. Variables being what they are, and not many people putting effort into multiple builds makes it complicated to make a best guess on size needed. Sorry for the long winded post. Thank you for your input!

:-) What starts out as a simple and very basic question often leads to complicated issues the deeper you get! This is a fact of life.

I would guess your biggest heat loss is through the pool surface. Evaporative cooling is quite efficient that's why you sweat. Covering the pool or floating 1000's of plastic balls on it reduce that.

Your best flow/heat conversion is a matter of conjecture because there will be so many variables involves. Best, (engineering), solution is build it - see how well it works, improve what you have to strengthen the weak points.

HidiousTak (author)  rickharris1 year ago

yep, that's how it is with all my projects... I do have a solar cover for the top. That should reduce the heatloss from the pool.

Makes a huge difference. Some years ago I visited a pool in Germany and the outdoor part was covered in coloured plastic balls to keep the heat in but allow swimming. Really odd. (it was also snowing.)

Probs your "Best answer" right here (Hint, Hint :P )

Black PVC inside whats basically a Solar Oven sounds like the most effective option over a proper pool heater.

Btw nice Bungee-Cord Solution !


HidiousTak (author)  rickharris1 year ago

but will that work on a sunny December day?

Yes, just to a lower temp. Much depends on how well you insulate and if you double glaze the front.

HidiousTak (author) 1 year ago

ok, what if I build a shallow box and line it with pond liner. Clear plastic on top. Attach radiant floor wire to the bottom and insulation below that. Pump water in on a low spot and out on a higher spot.. Should I make the bottom of the box metal to spread the heat more? Will this fry the Radient heat flooring wire? I just want to be able to turn on the heat if it's incredibly cold out for some reason. I would think it would be at least as effective at heating the water as solar. What about getting a space heater and pumping hot air into the trapped small area would that be effective? It would be nice for it to no require more breakers and just be able to plug into my outdoor outlet.

Watts are a measure of power - In general power in = power out - any losses.

You electrical heater will need to be VERY powerful (high wattage) to heat up an entire pool

Imagine if it was 200 watts per 2q meter (yard) the highest power heating pad I can find in a hurry, and your box is 6 feet x 6 feet that's 4 sq yards. 4 x 200 is 800 watts of heating power that's somewhat like putting a spotlight bulb in the pool and expecting it to heat the pool up.

Depending on the time of year and where you are on earth the ground around you may get as much as 1367 watts per square meter. An insulated box with double glazing on the front will easily boil water if there is little flow.

HidiousTak (author)  rickharris1 year ago

ok what do you think is more effective the box with water openly flowing in and out via pump or the hoses on metal with clear plastic top?

Do a bench test !

Build two small boxes, one filled with water and the other will the black Pvc Pipes and just set the out in the sun (no need for the pump quite yet)

Come back in a few hours and use a termomiter to tell wich is warmer !

I think my first suggestion was the most effective.!



Food for thought in those links.

To answer your question more directly you need a large heated surface area to allow maximum contact area with the water to give the fastest heat transfer.