You may need to brace yourself for thicker sweaters and thinner wallets next year, as Rochester Gas & Electric and New York State Electric and Gas are seeking sizable rate increases.

If approved by the state Public Service Commission, the higher rates could go into effect by August 2010 and raise the average bills of households served by the utilities by roughly $400 to $450 a year.

According to the companies, which are owned by the Spanish utility Iberdrola SA, the increases are needed because of rising expenses. The two indicated that with the added income, they would increase their investments in infrastructure to improve reliability, the Home Energy Assistance Program for the needy and the vegetation management program that cuts back trees near power lines.

"NYSEG and RG&E rates have not increased since the mid-1990s," said Clayton Ellis, a spokesman for the Rochester-based companies. "Costs that we do not control, such as supply costs, taxes and mandated fees, may have impacted customers' bills, but NYSEG and RG&E rates have not increased."

Under the proposal, the average RG&E residential electricity bill would go up by $11.86 a month, or 16.1 percent, while the monthly gas bill would increase $21.03, or 15.2 percent. NYSEG increases would be $12.39, or 18.6 percent, for electricity and $25.34, or 17.4 percent, for natural gas.

The varying amounts reflect that RG&E and NYSEG are separate companies with different revenue requirements for maintaining service, Ellis said.

The companies said their operations already are lean, with steps such as salary and hiring freezes and business travel reductions having been implemented. They said they need more money because their borrowing costs are up and materials prices have risen substantially - the cost of a copper power line has increased 67 percent since 1996, while a pole-mounted transformer is up 149 percent.

Iberdrola bought the companies in September 2008. As a condition for approval of the $4.5 billion deal, state officials prohibited the companies from seeking rate increases for one year.

Nevertheless, RG&E and NYSEG applied for higher rates in January, saying the frozen credit markets that followed last fall's global financial crisis had created extraordinary circumstances. In April, the state PSC shot down the request. Now, a year has passed and the companies are trying again.

The idea of higher rates did not sit well Friday with a number of area residents and businesses.

"Our orders are few and far between - supporting a rate hike would be really difficult," said Thomas Coburn, facilities engineer at Rochester-based gears manufacturer Gleason Works. An increase in the transition charge the company pays RG&E means Gleason already figures to see its annual electricity costs go from about $1.4 million to $2 million, Coburn said.

"We're in a pickle here," he said. "If they get (that big) a rate hike on top of the transition charge, we're going to have to do something drastic. I don't know what that is."

Ann Heizmann of Castile, Wyoming County, personally handed Gov. David Paterson a letter in March in opposition to the first request for a rate increase. The latest proposal is no more defensible given the current economy and people's inability to absorb larger monthly bills, she said.

"It's asking a lot from people," Heizmann said. "New York state, I don't think we can handle these rate hikes, with the unemployment."

The PSC has an 11-month deadline for ruling on the request. No dates have been set for hearings.

The commissioners and a PSC administrative law judge have the authority to reject, approve or modify the request. The ultimate decision is to be based on whether the rates "are fair and equitable and that the safety and reliability of the system are maintained," said PSC spokesman James Denn.