Sonoma County will use $2 million in state grant funds to help speed up payments to contractors installing solar panels and other power and water saving upgrades for homeowners in the county's energy retrofit program.

County officials said they hope the streamlined payment schedule would make the retrofit program more popular among builders and lead to more inquiries and contracts for residential retrofit projects.

"This is another win for the county program," said Efren Carrillo, chairman of the Board of Supervisors.

The grant funding does not apply to commercial retrofits under the county program.

Supervisors on Tuesday accepted the funding from the California Energy Commission. The federal stimulus money is an addition to the $3 million grant the commission awarded to the county in March to support other improvements and initiatives in the 2?-year old retrofit program.

The county has until March to spend the total grant of $5 million.

The $2 million addition will support a revolving fund from which the county will be able to more quickly disburse money to participating homeowners, allowing faster payments to contractors.

Currently contractors must wait up to six weeks to be paid because the program relies on disbursements from bond financing available only at the start of the month.

Disbursements from the new revolving fund — which will be reimbursed from the bond financing — will allow payments within five days of receipt of an invoice, said Diane Lesko, assistant manager for the Sonoma County Energy Independence Program.

"That's going to be huge," Lesko said. "It's going to make the program much more user-friendly for contractors and customers."

The county will be able to retain the grant-supported revolving fund as long as it makes $2 million in disbursements for residential projects by the March deadline.

Lesko said she thought that would be possible based on figures that show an average monthly disbursement of about $750,000 for residential projects since July.

Meanwhile, the program also is expanding its discount for home energy audits. As part of the initiatives supported by the initial $3 million energy commission funding, the cost of the audits will be covered entirely by grant funding, a value of about $700 per audit, Lesko said. The previous arrangement covered three-quarters of that cost.

The audits focus on many aspects of energy use, including windows, doors, insulation, weather stripping and heating and cooling systems.

Audit customers are not required to participate in the retrofit program, Lesko said.