DIY Friday: Solar Hot Water

First it was soaring gas prices, then the cost of food – now it appears that the price of natural gas will surge fast.

The consequence? The cost of heating your home will be a lot more expensive next winter (especially if you’re in Wisconsin). What to do?

Well, if you’re in Iceland, just dig a hole. An amazing 90% of homes are heated with geothermal energy. Of course, with my luck, I picked this unheated, sod-roofed backpackers hostel/shack (highly-recommended, btw) on my recent stay in Iceland. Chilly nights.

But, if you’re still States-side, the geothermal option probably won’t work. So beyond simple conservation, let’s start by finding a simple and energy-free way to heat our water – the sun!

Way back in 1984, Mother Earth News brought us the plans for building an integral passive solar water heater (IPSWH):

For the do-it-yourselfer searching for an inexpensive, easy-to-build solar water-heating system, the integral passive solar water heater (IPSWH, pronounced ipswah ) is a dream come true. All you need to get going on this down-to-earth water warmer is a discarded electric water heater tank rescued from the local dump, a homemade plywood box to house it in, a can of flat black paint, a sheet or two of used window glass or clear plastic, a few common plumbing fittings and some pipe and insulation. Combine all that with some spare hours of satisfying sawing, hammering and wrench-turning, and you’ll have an ongoing supply of hot water provided virtually free from that friendly furnace in the sky.

The article gives a good how-to on the building process, and a fairly exhaustive explanation on the different types of active and passive solar water heaters. And just three months ago came Mother Earth’s modern update. Among the findings: the solar water heater payoff could be dramatic, especially considering rising energy costs:

Solar water-heating systems have minimal—sometimes zero—operating costs, and maintenance costs only about $2 per month. When all costs for purchase, installation, maintenance and operation are taken into account, a solar water heater usually pulls even with an electric heater after just eight and a half years, and equals a gas heater in about 15 years. From then on, through the expected 40-year life of the solar system, you’ve got FREE hot water.

When you’re ready to roll-up your sleeves, Instructables has the how-to pictures and directions. Build it Solar posts some other plans, including a pretty wild idea to use the energy from composting to heat water. And this enviro-solution is just a damn good excuse to throw a party (instructions are available here).

But, despite all the fun ideas, this is one of the few DIY projects that I encourage you to get some help. If you really want to save some money, reduce your CO2 output, and keep the system cooking for 40+ years, I’d skip the bottles and buy a system.

Have a great weekend!



  • Shaun Bassolino says:

    Solar water heaters are great because they are eco-friendly. I myself use solar water heaters at home because they are energy efficient and of course cost less.

    Kindest regards

  • bb2 says:

    This is a great read! Thanks for posting.

    May I add…

    One of the most serious issues of mankind that we have not given enough attention to is from where we are going to obtain our energy. There’s a lot of talk of fossil fuels being depleted and the need for alternative energy sources, but I do not think our society as a whole understands how serious this all is. The problem is much much bigger than people realize. I don’t think there is a single solution. We got to do it all — solar electric, solar thermo, geo, wind AND nuclear. We need an infrastructure to make these four sources (and others) work together. Many say that solar is too inefficient. yes, it’s low. But if your gas tank is empty — solar is pretty impressive. Wouldn’t it be great if building codes required that all new construction cover the roofs of buildings with enough solar panels to make the structure produce 110% of it’s energy needs. More use will no doubt bring more research, which in turn leads to further improvement. Same sort of approach can be made with wind and geo. Nuclear can be the stable filler. Some day. But sooner is better.

  • Tessa Cowdery says:

    I use solar water heater at home because they are energy efficient.

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