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Clean Power DIY solar pool warmers look like lily pads

Published on July 22nd, 2014 | by Jo Borrás


DIY, Zero-energy Pool Warmers Could Save You Thousands

July 22nd, 2014 by  

DIY solar pool warmers look like lily pads

There’s nothing better than a swimming pool for beating the summer heat and spending some quality time with friends and family outdoors, but keeping a pool warm can be prohibitively expensive and incredibly wasteful. Fortunately, these simple-to-make, DIY pool warmers concentrate the energy of the sun to release up to 500 BTUs per hour into your pool. Each!

All you need to get started making these lily-pad style pool warmers are hula hoops, some readily-available polyethylene film, a few clamps (or an extra set of steady hands), a sharp blade, and a slightly modified soldering gun to get everything to stick together.

Keep in mind, it might take a bunch of these lily-pad pool warmers to keep your pool warm, and the original Make article seems to think that 50% coverage is what you’re really after. Still, given the bargain-basement unit cost of these things and their high potential output/heat-retaining insulation, you’ll probably make your money back in no time. You can check out the super-over-simplified version of the instructions for making your own zero-energy pool warmers, below …




Cut the polyethylene film to the approximate size of the hula hoops you bought.




Clamp (or find someone willing to hold) the polyethylene film to the edge of the hula hoops.




Use the slightly modified soldering gun to melt, or “spot-weld”, the film to the edge of the plastic hula hoop. Next, use the pointed tip of the soldering gun to puncture 9 small vent holes in the film, one in the center and the rest distributed in a circle of about 24″ diameter. This is critical, because, without these vents, air bubbles would form under the stretched polyethylene and reduce the heat transfer.




Trim the edge of the film so it more neatly aligns with the hula hoop. This is purely an aesthetic step.




Toss those DIY lily-pad pool warmers into the pool and start making that freeloading sun work for you!


… if that’s not enough, just head on over to the original article on Make.com for a much more in-depth, step-by-step guide to lily-pad construction. In the meantime, you can watch Make’s lily-pad pool warmer promo video, below. Enjoy!


DIY Solar Pool Warmers

Source | More Photos: Make, via Pinterest.

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About the Author

I've been involved in motorsports and tuning since 1997, and write for a number of blogs in the Important Media network. You can find me on Twitter, Skype (jo.borras) or Google+.

  • Peter

    I need to try this ! The solar blanket for our odd-shaped pool is such a pain that it rarely gets used . . . so we pay around $300/month CDN to keep our pool at 84 degrees with natural gas (Ottawa Canada)

  • Fishar

    Are you serious?…. hmm guess you are. Umm this is a spin-off 1960’s technology but if you use 1970’s technology and use a bubble wrap plastic pool blanket you’ll get a far greater level of efficacy and without the bacterial problems of black plastic. They are clear, roll easily, no bacteria growth issues and you actually have a clear thermal blanket that covers a multitude of uses.

    BTW… all those hoops, use of electricity, etc etc…. Did you ever stop to consider the size of the latent carbon footprint you placing in the pool using such an idea?

    Just an observation mind you. Sometimes old farts and “history” have their place. 🙂

  • GaryBIS

    Interesting idea, but I agree that a full pool cover would be more effective and probably less work to do.

    There are a lot of pool heating solar collectors that DIYers can do that are pretty simple to build and work quite well. As a solar heating system, they are very simple in that they pool itself is the storage (so no storage tank), and the pool pump can also act as the collector pump.

    Even buying the commercial polypropylene pool heating collectors at about $5 per sqft is a very cost effective DIY pool heating project.

    Lots of DIY collectors on the BuildItSolar pool heating page — proven designs that people have built and reported on with details.

    Gary Reysa

  • spec9

    Not only does it heat the pool, it also reduces evaporation and thus save fresh water.

    • MarTams

      Not with the freely floating hoops. Water splashes and collects into the upper surface where it can evaporate and have the cooling effect. Small waves from wind, swimmers splashing, water will collect over these hoops and they will evaporate. Even in the picture above, there are tiny puddles of water above the hoops, and it lessens the heating effect.

  • MarTams

    A typical swimming pool of 30′ x 15′ x 5′ deep would lose about 612,724 BTU/day just on evaporative cooling alone on a typical summer day. Distributed over the sunshine hours, the average per hour heat energy loss would be 51,000 BTU/hr. To heat the same pool by 10 F degrees, would need 1.4 Million BTU’s. These hoops don’t cut it. Better to cover the pool to heat it up.

  • MarTams

    More expensive and more work than necessary compared to simply NOT cutting and glueing circular sections. Simply cut the poly sheet into the shape of a pool, then cover the pool with it. If you only need half, cover half and use the other half. You can attach the sheet to a roller if you like. Most pools have these roll-out sheets already and it keeps the pool clean from debris when not in use. All you need is to replace with a heat absorbing material. These hula hoops are backwards thinking!

    • MarTams

      And if you cover the entire pool with the same poly sheet, you also prevent the major cooling factor of the swimming pool, the cooling effect of heat of vaporization. Having the entire pool covered with a sheet that you can roll and unroll would have many advantages.

      • Bob_Wallace

        There have been some reports of children getting trapped under the cover.
        Just a heads up….

        • MarTams

          Even without covers, there are always constant reports of children drowning in the pool. The pool covers rarely contribute to this. So that you also know.

        • Yeah, that would be my concern. With these, they’d just float away.

        • Pat Campbell

          Yep, it could delay finding a small child who falls in thinking the pads are something to climb into or walk on… Maybe the standard black poly coil on the roof method would be a better idea.

          • MarTams

            That is why in California, all households that has a child living with them are required to have a fence with a safety lock around swimming pools. Putting a cover over those pools should not matter, and a distorted cover is a better indicator indicator that someone has fallen into the pool than the one with no cover. Logic my friends.

          • Bob_Wallace

            ” distorted cover is a better indicator indicator that someone has fallen into the pool than the one with no cover. Logic my friends”

            I wouldn’t bet on that….

    • Birdie Duplessis

      Well I had one of those blankets for the pool but our pool is an above ground & it is very difficult to find a place that isn’t dirty to lay the blanket down. (Maine is very rural). The Lily pads are so easy to stack on the deck & don’t take up a lot of real estate while sitting off to the side. The poly sheets you are referring to are only about 4 ft wide so that isn’t sufficient to cover the pool. The blanket we bought was quite costly & & started to disintegrate with the chemicals & sun.

  • Kompani

    One of the best, low cost, energy saving ideas I have seen, brilliant, everyone with a pool who has no solar heating should be doing this.
    Pool maintenance people should be making these in their spare time as a nice sideline!

    • I was psyched when I saw this on Pinterest, also- you can’t imagine what my family in Florida pays to heat a small pool!

      • Jan Veselý

        It is such a waste not to use sun in the SUN state.

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