What if you could make a DIY solar water heater for a few bucks in materials?

Guess what? You can.

While I was in Indonesia, I had the pleasure of meeting Pak Rus Alit at the Bali Appropriate Technologies Institute (BATI). While there, we got to see a wide range of simple, low-tech solutions for living.

One that really struck me as useful was the solar water heater he created.

Check this out:

The BATI DIY Solar Water Heater

This DIY solar water heater consists of a metal tank on a base with a pyramidal frame over the top covered in clear plastic sheeting.

The base was constructed of fire bricks with a channel running through under the tank in which a fire can be constructed.

Water is piped into the bottom of the metal tank and emerges from the top.

It’s a simple system for hot water. When I was at BATI, the weather was overcast but the water was still pleasantly warm.

Where I live in Central America, people often install solar water heaters on their roofs. It seems like a great idea to take care of the tropical sun – until it rains for a day and you have to take a cold shower. The pre-made systems are also expensive.

This design, which I presume is by Pak Rus, also gives you the option of heating with gas or wood. The downside of it is that the pipe has to be disconnected in order to remove the greenhouse top and light a wood fire inside, which is an unnecessary complication. If I build one I’ll design it so I can take the greenhouse portion off without undoing any plumbing. I hate plumbing.

The plastic sheeting needs to be UV resistant. I think some corrugated polycarbonate panels would be the way to go if you can get them. They are cheap and rigid and stronger than plastic film.

Overall, this is a nice solar water heater design. During the sunny time of the year you’ll have plenty of hot – or at least warm – water, then you can add a gas burner or a wood fire when it’s cool and rainy.