Solar water heating has been around since the Mayans used stones heated by the sun to warm their sacred baths. A well-designed solar thermal water-heating system can operate efficiently practically anywhere in the United States.
- The moderate to warm climates of the southern and western parts of the U.S. are well suited to the traditional flat-plate collector.
- For the parts of Europe and the U.S. with colder climates, the evacuated tube hot-water solar collector is quite efficient.
A solar thermal water heater is 60-70% efficient in collecting the sun's energy, whereas the average photovoltaic system is in the neighborhood of 14-20% efficient in converting the sun's energy.
- As a result, heating water with PV usually does not make economic sense.
- Additionally, a solar water heater can operate efficiently even where there is some shading, while a PV system's performance is significantly reduced when partially shaded by adjacent buildings or trees.
- Many homes that won't support an efficient PV system can produce a good amount of hot water with a thermal system.
For a family of four, a solar water heater supplying 50-70% of the domestic hot water should cost $6,000-$8,000. The payback can be as short as five or six years.
- A federal tax credit can reduce the cost by $2,000, and some states and municipalities offer additional incentives.
- The Database of State Incentives for Renewables & Efficiency (DSIRE) has details of incentives for your home state of New York, and all other states, too.
Check GreenHomeGuide's Find A Prodirectory tofind solar installers near you.
For more information:
The Department of Energy publishes an online Consumer's Guide to Energy Efficiency and Renewable Energy that includes a good explanation of solar water heaters.
YouTube has a video of a solar hot water installation.