Brad Lancaster of harvestingrainwater.org shows us his solar water heater...
He hasn't paid a dime for a hot shower in 30 years...great way to screw the gas company.
From Brad Lancaster: Our batch-style solar hot water heater was designed by Solar Toby and Bill Cunningham of https://www.southwest-solar.com/.
It was sized, and built around, the salvaged double-glazed tempered glass we got from Bill. Two pieces of 1-inch thick fiberglass insulation with foil backing heat taped together is what the batch/box is made of. The galvanized sheet metal on the exterior is just to protect the insulation from woodpeckers.
We used gas hot water heater tanks, because they have a flue pipe down their centers that results in more surface area for faster heating than you'd get with an electric water heater that has no flue pipe. And I misspoke in the video. We got the water heaters new (not salvaged), then disassembled them, and painted them black (using high temp black paint for grills and such) for use as solar water heaters.
It has worked great as our sole source of hot water for two households of 4 permanent residents total for over 30 years.
For more info on affordable and effective passive solar heating and cooling strategies check out Brad's website https://www.harvestingrainwater.com/s...
and the full-color edition of Brad's book "Rainwater Harvesting for Drylands and Beyond, Volume 1, 3rd Edition", which you can get at deep discount, direct from Brad, at https://www.harvestingrainwater.com/p...
The book has a whole chapter and an entire appendix on sun & shade harvesting.
I found a YouTube link in your post. Here are links to the same video on alternative frontends that protect your privacy: