Solar Hot Water is taking off in countries all around the world. Lester Brown at the Earth Policy Institute has a great piece up this week with updates on this important technology:

The pace of solar energy development is accelerating as the installation of rooftop solar water heaters takes off. Unlike solar photovoltaic (PV) panels that convert solar radiation into electricity, these "solar thermal collectors" use the sun's energy to heat water, space, or both.

Far and away the world's leader with nearly 2/3 of the world total, China had 1.8 billion square feet of rooftop solar thermal collectors installed by the end of 2010, enough to supply 112 million Chinese households with hot water. With some 5,000 Chinese companies manufacturing these devices, this relatively simple low-cost technology has leapfrogged into villages that do not yet have electricity. For as little as $200, villagers can install a rooftop solar collector and take their first hot shower. This technology is sweeping China like wildfire, and Beijing will likely exceed their goal of nearly doubling that by 2020.

Other developing countries such as India and Brazil may also soon see millions of households turning to this inexpensive water heating technology. Once the initial installment cost of rooftop solar water heaters is paid back, the hot water is essentially free.

In Europe, where energy costs are relatively high, rooftop solar water heaters are also spreading fast. In Austria, 15 percent of all households now rely on them for hot water. Germany is also forging ahead. Some 2 million Germans are now living in homes with rooftop solar systems. Roughly 30 percent of the installed solar thermal capacity in these two countries consists of “solar combi-systems” that are engineered to heat both water and space.

Where is the US?

Despite being a large, sunny country the US ranks 10th in the world for installed solar hot water - much of it for pool heating. In terms of solar hot water capacity per person, the US comes in a disappointing 36th place.

The good news is the US market has grown steadily since 2006. Led by Hawaii, California, and Florida, annual U.S. installations of these systems have more than tripled since 2005, writes Brown.

With strong state incentives in place, high-quality equipment at competitive prices, and no-money down financing, there has never been a better time to take advantage of the energy-saving benefits of solar hot water. This will be an exciting market to watch in 2012.