If you’re like most people, 38% of the natural gas used in your home goes to heat up water. A solar hot water heater can cut your water heating bills by three-fourths. There’s a 30% federal tax credit for solar water heaters installed by 2016 and, in California, you can get a cash rebate up to $1875 for solar hot water heaters installed after July 15, 2009. Another option is a tankless (aka “on demand”) water heater that heats water on an as-needed basis rather than keeping a tank full of water heated all the time. A tankless water heater can be used alone or in conjunction with a solar hot water heater for maximum efficiency.
If you’ve ever left a bottle of water in a hot car, then you pretty much understand how solar thermal works. It’s pretty simple–sure, manufacturers have refined the process for maximum efficiency, but basically all that’s happening is that the sun pre-heats the water so that your gas or electric water heater has to do much less work. That’s it–an elegantly simple technology that has the potential to spare the planet millions of tons of greenhouse gas emissions every year.
The world is in the midst of a solar water heating revolution though, as usual, the United States is limping along far behind the pack. China is in the lead, with 27 million rooftop solar water heaters, enough to take the place of 49 coal-fired power plants. In Spain, Portugal and Israel, new buildings are required to install solar water heaters. Europe, Japan, India and Brazil are also hot to trot for solar thermal and have set ambitious goals for widespread adoption by 2020.