After a 20-year hiatus, solar water heating is experiencing a comeback as more homeowners look for ways to reduce their energy consumption. Recently named one of the top 10 technologies for 2007 by HUD's Partnership for Advancing Technology in Housing (PATH) program, solar water heating conserves natural resources, reduces carbon emissions, and can save money.
"What we're seeing now is a renaissance of interest [because of] new federal tax credits and the rising price of energy," says Noah Kaye, director of public affairs for the Solar Energy Industries Association (SEIA).
Photovoltaics, or solar electricity, get most of the attention when builders consider renewable energy systems, but solar water heating offers a more cost-effective way to incorporate renewables into a home than photovoltaics, manufacturers say. "Solar water heating can be as little as one-tenth the cost of photovoltaics," says Jeff Mahoney, North American representative for Rheem USA's Solahart division. Plus, the payback on a solar water heating system can range from five to 10 years, faster than a photovoltaic system.
"A good system costs no more than $8,000," says Donavin Gratz, president of Green in Green, a solar installer in West Hatfield, Mass. "After seven years, it's paid for and the rest of [water heating costs are] 80 percent paid for. People need to think long-term."
Installation Considerations
Solar water heating works best as a supplement to standard and tankless water heaters, according to most manufacturers. Nearly anywhere in the U.S., a solar water system can supply 60 percent to 70 percent of a home's domestic hot water, says Tim Bowler, solar sales and technical services manager for manufacturer Stiebel Eltron.
Different types of systems are available to meet the conditions of most regions. Passive systems are designed for warm climates and can store heated water in an integrated tank or in the collector plate. Active systems use an antifreeze fluid as well as water to collect heat, so they are ideal for colder climates. Pumps move the heated water or fluid from the collector to the storage tank in an active system.
"In the right conditions, it works very well," says Bob Tortorice, president of Building Alternatives in Franconia, N.H. But, he cautions, "Solar doesn't work for everyone. You can't get solar if your site is facing north."
"You can't easily turn it off," adds J. Craig Robertson, president of Heliocentrix, a solar collection installer in Williamstown, Mass. "If you make the system too big, the hot water tank could overheat in the summer. You have to make a provision for that."
Collectors can be installed nearly anywhere the sun shines for six to eight hours each day, but the best spot is nearly always on the roof. Some manufacturers have developed less obtrusive collectors, such as Fafco's Hot2o system. Its collector panel is made of black polymer tubes with a much thinner profile than flat-plate or evacuated-tube collectors. Dawn Solar's collector tubes install below roofing materials, protecting them and keeping them out of sight.
Current federal tax credits are set to expire in 2008, leaving builders and homeowners little time to act, but two bills pending in the House and Senate could extend the current legislation's credits for solar energy installations until 2016. Even without ongoing tax credits, though, contractors with green-minded clients are in a unique position to offer a non-polluting source of hot water that helps reduce a home's contribution to global warming.
--This story first appeared in Custom Home magazine. Diane Kittower contributed to this report.
SOL 25 Plus Flat-Plate Solar Collector
Stiebel Eltron. The SOL 25 Plus flat-plate solar collector, which can be combined with the company's tankless water heating system, is ideal for domestic water heating, space heating, and swimming pool heating. Each panel's 28 square feet of net effective surface area results in a maximum output of 21,000 BTUs per day. The 3-inch-thick panels use a polypropylene glycol solution for heat transfer. 800-582-8423. www.stiebel-eltron-usa.com.
Solahart Free Heat Series Solar Water Heating System
Rheem USA. The passive, closed-circuit Solahart Free Heat series solar water heating system uses a multi-flow collector panel that exposes more water to the sun's radiation than standard collector designs, heating water faster, the maker says. Its black-chrome selective surface provides high-efficiency energy absorption. Integrated storage tanks range in capacities from 48 gallons to 116 gallons. 334-260-1586. www.rheem.com.