Both! Here's the story:

As most of you know, I live off the grid. Way off.

Because we're on solar power, having a traditional electric water heater is out of the question. With butane at $3/gallon, that gets expensive too, especially when you're living entirely on donations. Thus, for the last 8 months, I've not had hot water at home. This means cold showers every day.

So I've been looking for a solution to this problem. Especially since occasionally during winter, it can get into the 50's at night (poor me, right?), and that's an awfully cold shower.

A friend of mine sent me the attached plans to a solar hot water heater that's being built quite a bit in Brazil. They're translated (not terribly well) from Portuguese. I was able to understand them well enough to give it a shot though. The same friends came down from the States to visit and we decided to build it while they were here.

To spare you from the pain of having to decipher that document: here's a quick summary. As with most solar water heaters, there are two parts - a storage tank and a heat collector. The design uses as many renewable materials as possible. The heat collector is built out of "trash" - Empty plastic bottles and cardboard milk cartons - and inexpensive PVC pipe and black paint. For the tank I just used two different sized trash cans and filled the void between them with Styrofoam and that "Great stuff" spray-foam-in-a-can. It does not require any circulating pump as it relies on a thermosiphon effect to circulate the water.

My first effort at building it is admittedly a bit clumsy compared to the finely tuned ones that they build in the plans I've attached, but I think that I can fine-tune the design to make it cheaper, easier and more efficient using the materials I can gather here.

Bottom line: For about $100 USD and some time walking the beach collecting plastic bottles, I now have toasty hot showers at night. The best part: ongoing cost is $0.

If anyone is interested, I'll post some pictures of my build when I get a chance. I'm currently in the city for about 4 weeks.