Homeowners in Herndon, Vienna and Falls Church have until Tuesday to take advantage of a program that can make it more affordable to start powering their homes with solar energy.

The Solarize NOVA program helps homeowners save money on converting to solar power through free home assessments and bulk discounts, said officials with the Local Energy Alliance Program, which sponsors the initiative with the Northern Virginia Regional Commission.

Rebates, loans and tax credits are also available to help consumers finance the conversion to solar, said Angela Hopgood, solar program manager for LEAP.

Homeowners can lock in discounted rates for solar installation by registering for the program online and signing a nonbinding letter of interest by Tuesday, Hopgood said. Solarize NOVA has contracted with three Northern Virginia companies to do the installations at a reduced rate.

The installers review data on each home’s utility use and conduct site assessments to develop a proposal, Hopgood said.

“They can design a system that makes sense for the energy use of that particular home,” she said. “All of the systems are customized to the needs of the homeowner.” After a company makes a formal proposal, the homeowner has 30 days to sign the contract, she said.

The Solarize NOVA program was piloted last fall in Leesburg and Loudoun County, resulting in 17 signed contracts, Hopgood said. The contracts were valued at a total of $438,000.

Martin Boyd of Sterling signed up for the program because of his concern about global warming.

“I decided to jump up and be a better steward of myself and what I’m doing to the environment,” he said.

Boyd said his power bill had been a little more than $100 per month. Since converting to solar energy, it has dropped to $7.63 a month, he said. His system produces more electricity than his home uses, so the only charge is for the connection to the distribution system, he said.

Boyd estimates that, based on anticipated usage rates and projected costs of electricity, his solar system will pay for itself through cost savings in about 11 years. He also expects that his house will sell much more quickly if he decides to put it on the market.

Because Boyd’s system produces more energy than his home uses, it supplies power back to the grid. In return, he is receiving the equivalent of one Solar Renewable Energy Certificate every month. The certificates’ values rise and fall like stocks, he said. Currently each certificate is worth about $50.

“So not only have I gotten my electric bill down to $7.63, I’m also making about $50 a month” through the energy certificates, he said.

Mayors David Tartar of Falls Church and Laurie DiRocco of Vienna decided to hold a friendly competition to help spur interest in the Solarize NOVA program. They have a wager to determine which community can enroll the greatest number of participants for free home energy checkups and solar site assessments, Tartar said.

“The losing locality will provide some food from a local restaurant to the winning council,” DiRocco said in an e-mail. “Food can be an enticing wager!”

As of last week, the competition appeared to be generating interest. Vienna led with 214 sign-ups; Falls Church had 174 and Herndon had 93, Hopgood said. Seven people had already signed contracts, and about 125 were in the process of working on agreements with the contractors, she said.

“I’m expecting that it’s going to be even more successful than Loudoun,” Hopgood said.

Barnes is a freelance writer.