Progress Energy customers saved an average of $235 a year by switching to solar thermal water heater, representing an average annual savings of 63 percent on the water heater portion of their power bill. 
Those are the results Raleigh-based Progress reported this week to the N.C. Utilities Commission to wrap up a pilot project using 150 customers to test the efficiency of solar thermal water heaters. As part of the year-long pilot, Progress contributed $1,000 toward each customer's cost of buying as solar thermal water heater.
The company says that more than 15 percent of electricity used in a typical home is used for heating water. Solar water heaters use the sun as their primary source of energy, with electricity (or natural gas) as a backup.
Solar water heaters are known for their high efficiency performance as well as their high price tags, costing about 10 times to 20 times as much as a conventional water heater. Progress reported that buying and installing the solar water heaters averaged $7,271 per household, ranging from $4,000 to $12,375 per home.
Homeowners rarely pay the full price, however. In North Carolina, solar water heaters qualify for a 30 percent federal tax incentive and a 35 percent state tax credit (up to $1,400), which would cut the cost by about half.
