Living outside Columbia, South Carolina, Robert Hersey and his family had become accustomed to the battle with heat and humidity that came with each summer – and the corresponding spike in their utility bills.
Temperatures inside the home could get above 85°F, even with their heat pump running at full power, thanks in part to a leaky black shingle roof that absorbed the sun’s heat and let cool air escape. “I would hold my hand up to the ceiling and could feel heat radiating down,” Hersey said. At night, to save money, the family would run the exhaust fan only, which drew moist air from underneath the house and created moisture and mildew problems. Energy bills could exceed $400 during peak summer cooling and winter heating months.
As a construction worker, Hersey sensed that the manufactured home could be made a lot more energy efficient. But he didn’t know how to go about it and the family didn’t have much money to invest, even if it would ultimately save them money.
The solution came when the Hersey home was chosen to receive an energy efficiency retrofit as a part of test program to evaluate potential energy savings for rural homes. The rural energy savings program is being developed by the nonprofit Environmental and Energy Study Institute (EESI), the Electric Cooperatives of South Carolina Inc., and Central Electric Power Cooperative Inc. (Central), the wholesale generation and transmission co-op that serves the majority of the state’s local distribution cooperatives.
The home received a Duro-last roof covering, which seals air leaks and adds insulation to keep heat outside and maintain cool temperatures inside. The near-white color of the Duro-last treatment also reflects more solar energy than dark-colored roofs.
“It’s made a big difference, we love it!” said Hersey, when EESI’s Jan Mueller visited with him in March, a few weeks after the retrofit. Spring temperatures had already reached into the 80s, but the real benefits will come at the height of summer when temperatures regularly reach the 90s and humidity exceeds 70 percent (a statistic that many South Carolinians observe carefully).
Roof retrofits like this cost an average of $6,000 and the energy savings are expected to payback that cost in less than ten years (Central footed the bill for the test project). Other homes in the project will receive more cost-effective retrofit options, such as improving insulation, sealing ducts, or replacing electric resistance heating with electric heat pumps, to test their effectiveness and impact on utility bills.
The next step in the development of the rural energy savings program will be to apply an “on-bill” financing program, where residents receive a low-interest loan to pay for their own retrofit costs. Loans would be paid back through installments on monthly utility bills. “We expect the energy savings to drive down bills for these families substantially during peak energy seasons,” said Mueller. “Two-thirds of that savings will be used to pay back the loan, and after the payback period, all of the energy savings will just be cash in the pocket.”
The on-bill financing pilot project will begin its first implementation phase starting in June, and EESI plans to share the lessons learned with other states and federal policymakers. The South Carolina program aims to ultimately retrofit more than 200,000 homes and save co-op members an estimated $280 million a year.