How to make a homemade solar heater for an above ground swimming pool (with an automatic schedule and smartphone control)

So a few days after setting up our above ground pool, we quickly realised that we were going to need to heat it, particularly as it was undercover, otherwise it was not going to be getting used very much.

After searching for an affordable and effective heating solution, I gave up and decided to make my own. And after seeing the results - an increase of over 5 degrees Celsius in a few weeks for an outlay of $50 - I thought I'd provide the details here, including how I setup an automatic schedule with the pool pump using a Belkin WeMo Insight Switch.

I will say, though, that the biggest contributor to keeping the swimming pool temperature high is the pool cover. They say that water evaporation results in approximately 70% of heat loss, so do make sure your pool is covered when not in use if you want good results.

This homemade solar heater took me about four hours to setup, which includes the trips to Bunnings. Incidentally, this was probably around the same amount of time I spent researching and driving around trying to find a ready-made solar heater to purchase.

All parts came from Bunnings, including the WeMo device. Total cost was $125.05 (or only $50.31 excluding the WeMo device).

Here's the full list of parts:

• 1 x Holman 25mm x 25m Black Poly Drip Irrigation Tube (1 x $35.89)
• 2 x Holman 34mm x 25mm Reducing Coupling (2 x $3.97)
• 2 x Toledo 21-38mm Perforated Clamp Hose Fit (2 x $1.52)
• 2 x Toledo 27-51mm Perforated Clamp Hose Fit (2 x $1.72)
• 1 x Belkin WeMo Insight Switch (1 x $74.74)

I did get the WeMo device at about a 25% discount to the RRP thanks to Dick Smith having it on special. Bunnings, per their policy, beat them by 10%.

Making most of Dick Smith prices. Bunnings beat them by 10% on this #WeMo Insight Switch. #IoT #homeautomation pic.twitter.com/uVHI9nI2b7

— Greg Solon (@gregsolon) January 5, 2016

The above ground swimming pool we have is an Intex 15ft x 36in Metal Frame Pool. This solar heater should work with most above ground pools that come with a filter pump. A pump is required, as the solar heater works by filtering water out of the pool, moving it through a length of black pipe that gets heated by the sun, and ultimately returning it back to the pool. The returning water should be slightly warmer, thereby slowly warming your swimming pool. Here's what the assembled solar heater looks like:

Setting this up is really a breeze. Essentially, all you need to do is extend the hose / tube that returns water from the pump to the pool with the black poly tube. The poly tube should be positioned to ensure maximum sun exposure - both in terms of its surface area and duration of day. Obviously, the hotter the day and the more sun exposure the flowing water gets through the black tubing, the better results you'll get.

I found the Holman 34mm x 25mm Reducing Coupling as the most suitable product to use for attaching the standard pool pump hose / tube to the black poly tube. This was secured using the appropriately sized Toledo clamps to ensure no water leaks. The same reducing coupling and clamps were used to connect the black poly tube back to the swimming pool. Here's what the two connections look like:

So there you have it, for $50 you can setup something similar. And after a few hot days you should be noticing your swimming pool water temperature rising. As mentioned above, do ensure you cover your pool to prevent heat loss due to evaporation!

So now comes the automatic scheduling. Unless you plan on running your pool pump 24 hours a day, you'll need to turn it on and off at various times. Given the pool pump powers the solar heater, it's best to turn it on in the morning and off in the evening to ensure it does get maximum sun exposure. You can do this manually, but it's a little mundane and you can forget some days. As stated above, my solution to this was the Belkin WeMo Insight Switch. The cost of the WeMo device is high and you can get some cheaper and simpler products at Bunnings that can automate turning on and off a pool pump, though given my interest in home automation I decided on dabbling a bit with Belkin's WeMo range. WeMo devices also provide smartphone control and the Insight Switch offers further functionality such as providing power usage statistic, which is an added benefit.

I have set my pool pump to turn on at 6:30am and off at 5:30pm daily. Here's a screenshot its power consumption today. I turned it off early as the temperature of the water increased to 29 degrees Celsius! I thought that was warm enough.

And here are some photos of the Belkin WeMo Insight Switch:

The WeMo device was very straightforward to setup and I didn't experience any issues. The WeMo Android app, somewhat disappointingly, is quite rudimentary. It has the basic functionality you would expect, though is not as polished as most smartphone apps. It almost seems as though it has been put together by a high school student working a summer gig at Belkin, rather than an experienced team of developers. Hopefully that will change with time.

So there you have it. A simple yet effective solar heater for an above ground swimming pool. It has achieved its intended outcome, as we have definitely used the pool more!