Homemade Solar Water Heater

Making a homemade solar water heater for your pool is relatively easy and inexpensive. Learn how to make one just in time for spring.

Do you need a solar water heater?

Here, in the Southern part of the Spanish Riviera, a lot of people have pools, but nobody seems to heat them. The warm weather usually comes sooner in the year than what I was used to in Michigan, so theoretically we should be able to use a pool sooner (and until later in the fall), but the cool nights mean the pool loses too much temperature during the night to make it comfortable. That’s why, a couple of years ago, we made a homemade solar water heater for our pool.

Making a homemade solar water heater is easier than you might imagine, and it doesn’t have to be expensive either.

What materials do you need to make a solar water heater?

To make your own solar water heater, all you really need is a bit of black garden hose, and something onto which you can coil it up and hold it into position. You then connect it to your pool filter so that the filtered water passes through your homemade solar water heater before it goes back into the pool. The idea is to warm up the filtered water as you filter it. If you aren’t using it with your filter, you’ll need some sort of water pump to push the water through your black garden tubing.

You can also connect this between your faucet and your pool to heat the water as you fill your pool. If you’re doing it that way, you don’t need to use a pump and rely on the force of the water coming from the faucet, of course.

I will say that you use up a lot more tubing than you would imagine. We made this last year so I can’t remember how much tubing we actually used, but I would take a guess at around 100m of tubing!

Depending upon the tubing you have hooked up to your filter, you will need to find adapters that will let you connect that tubing to the (probably) smaller tubing of your homemade solar water heater.

How does a solar water heater work?

The concept is simple, really…

Because the color black absorbs heat, when the sun is out and shines on your black garden tubing, it absorbs the heat of the sun and transfers it to the water that runs through it. The more hose you use, the more water you’ll be able to heat in the same amount of time. Make sense?
That said, the more tubing you have, the stronger the filter or water pump you’ll need to push the water through all of that tubing.

When we first made our homemade solar water heater a couple of years ago, we coiled the garden hose onto a cross made out of thin wood pieces, and held the tubing in place using plastic ties. They ended up being the most expensive part of the project, believe it or not! Because they were relatively pricey, we spaced them out a little bit too much, and the hose started to bunch up on itself during the course of the year.

Last year we decided to fix our homemade solar water heater by taking it apart and putting it back together on sturdier wood beams. With my husband being a fisherman, he had an idea of good knots to use to tie down our black garden tubing. After tying it all down, he decided to make sure it would hold together, and used two scraps of wood to clamp down the tubing to our wooden cross on two of the sides. So far it has held up pretty well!

Watch how to make a solar water heater

How well do these solar water heaters work?

When the water begins to come out of the hose, it is pretty hot, but it will cool down a little as more cold water runs through it.

You might think that it means that the homemade solar water heater isn’t working very well anymore, but if you compare the temperature of the water to the cooler water in your pool, you should notice that the water is still being heated quite a bit.

For the first time this year, we decided to leave up our above ground swimming pool as an experiment because it’s a hassle to take it down and clean and dry it, fold it, store it, and take it out to fill again!

We’d heard about people leaving theirs up all winter successfully, and decided to try it out for ourselves.

It worked out wonderfully, and this past weekend my son and niece were already playing in the pool!
They would have been playing in it weeks ago if it hadn’t been for the cool weather we’ve been having this spring.

Before they began to swim, I checked the temperature of the water in the pool, and it was under 80 degrees Fahrenheit. I didn’t think to check the temperature of the water coming out of the heater until after it had been running for a while and was feeling much cooler again, but even then that water was above 95ºF. It easily brought up the temperature of our small pool a couple of degrees after running a short time, and it made for more comfortable swimming for the kids.

Luckily, the warm weather has finally arrived, making me a happy girl!