Anyone here use a homemade passive water heater?

[OnionPatch]

I've been looking at different plans online for solar water heaters. After watching Live Earth, we really want to finally start doing something at home to unleash us from fossil fuels but we can't afford the solar heating systems that cost $1000 or more. (And we don't plan on living here for more than three-five years.) A home made passive solar heater would be perfect for us. My husband can make anything if he has a plan. We are in southern CA, where I burn my hand on hose water if the hose is left laying in the sun! We have a great place, facing south, to put the heater. I just wanted to get some advice.

For example, if we use an old heater, like these articles say, do we need to remove the outer shell? This article seems to indicate that. http://www.epsea.org/wtr.html but others don't mention that at all. Or maybe I'm just confused.

Anyway, I would love some advice or comments from anyone who has a passive system or has installed one.

Thanks!