CLEARWATER — Anyone who remembers Homer Villas, a public housing complex off N Betty Lane, wouldn't recognize the area now. It's now the Stevens Creek subdivision, a neighborhood of colorful single-family Habitat for Humanity homes.Now those homes are starting to harness the energy of the sun. "Progress Energy donated 15 solar water heating units for our affordable housing," said Steven Lightburn, vice president of development for Habitat for Humanity of Pinellas County. "To have this kind of resource available is unbelievable."TECO Energy Inc. also donated four units, two of which have been installed in Habitat houses in Oldsmar."With the way we build, the typical electric bill costs $100 to $150 a month," Lightburn said. "With solar water heating, instantly take some off and you're looking at going from struggling to people using that money to nurture the family."A total of 51 houses will be built on the 10-acre site of Stevens Creek, which is just south of Sunset Point Road. Habitat petitioned Pinellas County and the city of Clearwater to purchase the land after the Homer Villas were razed and the governments' plans to create a multipurpose area with retail businesses and moderate- to low-income residential housing fell through.To build the infrastructure of roads, lights, sewage, drainage and retention pond took two years. In late 2010, the first two homes were built and the first homeowner, a past tenant of Homer Villas, moved in.Each home is built to be energy-efficient. The solar thermal units are expected to save homeowners up to 85 percent off the hot water portion of their electricity bill, which is about 20 percent of the bill.Also, replacing a traditional water heater with a solar-powered system will reduce more than 40,000 pounds of carbon dioxide emissions over 20 years, said Jeremiah Rohr of Solar Source, the company that installed a solar water heating unit on the roof at 1851 Fuller Drive on Saturday.The unit doesn't generate electricity. It constantly heats 40 gallons of water using solar energy, so it saves on electricity needed to heat water. A backup system kicks in when the sun doesn't shine for two or three days.It has a solar collector with 4-inch diameter copper tubes and a storage tank. The tubes absorb radiation and preheat the stored water in a particular flowing pattern so water is heated and used, then the next tube of cooler water is heated by the sun. It's a passive system without pumps and works automatically. The cost of this particular unit, fully installed, is about $4,000."At the present time, there is a 30 percent tax credit on the unit," said Rohr. "We've installed nine so far in this neighborhood and have been a longtime proponent of solar hot water. This pays you back month to month. Florida has a fabulous free resource to take advantage of and no natural fossil fuel resources."Installing units to pre-existing homes takes years to recoup the cost. But with water bills on the rise, that number could drop. And for Habitat homeowners, the cost is built into the price of the house."We're appreciative to Progress Energy for their support of our program in general and particularly with the solar water heating systems," said Ron Spoor, chief operating officer of Habitat for Humanity of Pinellas. He noted that the 51 homes to be built in the Habitat subdivision will pay property taxes to Clearwater and Pinellas County.