SmartEnergyViews

Pacific Business News reports that a new state law in Hawaii requires all new single-family homes built after Jan. 1, 2010 to have solar hot water heaters. Home sites that do not receive enough sunlight can use some other renewable energy source. Homes may also have gas-powered tankless "instant" water heaters as long as the home has one other gas appliance.

Solar hot water heaters are far less expensive than solar PV (photovoltaic) electric systems, and the payback period is much shorter. According to the DOE, water heating represents up to 17 percent of national residential energy consumption.