Hot water from the sun

DALE QUINN, DALE QUINN, ARIZONA DAILY STAR

TEP program seeking to put solar systems in nonprofits, low- income households with aid of federal stimulus funds

Tucson Electric Power Co. is expecting $1.3 million in federal stimulus funds to help get solar water heaters into low-income residences and the offices of nonprofit groups.

And that means local installers also are looking to get the energy-saving appliances into more homes.

Jeff Shoemaker, the owner of Custom Solar and Leisure, said he's seen demand for solar water heaters increase recently. He said his company installed 30 in the last month, and competition has also been increasing among solar installers.

The main impediment for most people is expense, Shoemaker said, as it can cost $3,000 upfront to buy the water heater. State and federal tax credits offset some of those costs. The cost for non- solar systems varies, but it can run about $600 to $800, he said.

Solar water heaters don't work well in cool and cloudy weather, but people still don't have to worry about running out of hot water. Each has a backup gas- or electricity-fueled system that kicks in if the water gets too cold.

Still, with solar, most of the water is sun-heated, Shoemaker said.

"The system will account for 85 percent of the hot water," he said.

David Hermon, who's working on getting a solar-water-heater business up and running in Tucson, wants to use a broader approach. His plan is to sell solar water heaters to several homes - up to 12 - at once, thus reducing costs for installation and materials. Hermon, an Israeli native, said he doesn't understand why solar water heating isn't more widespread in Tucson.

TEP's stimulus money will be used, starting next year, to help pay installation costs for low-income households and nonprofit organizations, as well as to provide money for training installers of solar water heaters, utility spokesman Joe Salkowski said.

Contact reporter Dale Quinn at 573-4197 or dquinn@azstarnet.com

A CONSUMER'S GUIDE TO SOLAR WATER HEATERS:

* Estimated system cost $4,500

* TEP incentive ($750 plus 25 cents per kilowatt-hour of annual energy savings, usually adds up to another $750) $1,500

* Federal tax credit (30 percent after TEP incentive) $900

* State tax credit (25 percent up to $1,000) $750

* Adjusted cost $1,350

Source: TEP

THE SAVINGS

Energy savings can vary, depending on the amount of hot-water use. But if the system is saving:

* $15 per month, or $180 per year, it will pay for itself within eight years.

* $20 per month, or $240 per year, it will pay for itself within six years.

SIZE OF THE SYSTEM

The typical system installed in Tucson is sized for 2,750 kilowatt-hours in annual savings, under guidelines set by the Solar Rating and Certification Corp. The average Tucson home uses 11,000 kilowatt-hours of electricity per year and, in homes with an electric water heater, heating water usually takes up about 25 percent of an electricity bill.

HOW THEY WORK

Solar water heaters come in two main categories - passive and active.

Two types of passive systems:

* Batch: One or more water tanks inside a solar collector. The water warms up right inside the tank, and either gravity or natural convection - the tendency of hot water to rise - moves water from the tank to a home's pipes.

* Thermosiphon: The water tank is separate from the solar collector. Cold water moves through the tubes of a solar collector, and natural convection pumps the resulting hot water into a storage tank. From the storage tank, the water travels into the home's water pipes.

Active systems typically fall into one of three categories:

* Direct: Water moves through the solar collectors and into a storage tank with the help of electrical pumps and controls.

* Indirect: Instead of heating water, the solar collectors warm a "heat transfer" fluid, such as a food-grade antifreeze solution. The solution is pumped through the solar panel and heated. The solution is piped around water in a storage tank, so it heats the water, but there is no contamination between the antifreeze solution and the drinkable water.

* Drain-back: A drain-back system is like the indirect system except that it uses distilled water as the heat-transfer liquid, and it has a separate "drain-back" tank for the distilled water. Pumping all of the heat-transfer liquid out of the system and into an interior tank makes it work for colder climates, because the liquid isn't exposed to extremely cold weather.

Source: HowStuffWorks.com

LEARN MORE

More information and a list of TEP-approved installers is available at tep.com/Green/ Home/Solar/ spaceheating.asp