To the unobservant, the rushed, or those simply caught up in the routine of another trip to get the mail, the outwardly quaint building to the east of the East Hampton Post Office on Gay Lane might appear to be relatively unchanged since its days as a blacksmith shop.

But a walk from the Amaden-Gay Agencies’ front door to the rear takes a comically long time, as a visitor treads a carpeted path past meeting rooms, office after actuarial office, and at last through a great hall of a room filled with scores of filing cabinets giving it the air of a city morgue, a paper-record repository of a town’s desire for indemnity.

The deceptive size of the insurance agency matters for two reasons. With a computer humming in every nook and cranny, it draws a lot of electricity. Conversely, with all that floor space, 7,500 square feet worth, Amaden-Gay has the commensurate roof space to carry enough solar panels to forever remove it from the Long Island Power Authority’s accounts receivable.

The first stage of a project to do just that is complete. The company that has been selling insurance policies for 116 years has teamed with one not yet a year old, GREENLOGIC, to put forty-two 208-watt solar electric panels on 700 square feet of two south-facing roofs.

The job started on June 13, and three and a half days later the building was partially powered by the sun.

“It’s the first solar system in the village,” Marc Clejan said last week. He owns GreenLogic, a provider of alternative energy products and services based in East Hampton, with his business partner, Nick Albukrek. “And we believe it’s the first commercial system in town.”

That system is 8.7 kilowatts, and it comes with a $63,000 price tag. But federal, state, and LIPA incentives to install solar units are now so generous that after all is said and done, the net cost to Amaden-Gay will be, according to GreenLogic, $11,500.

“Last year’s new tax law,” Mr. Clejan said, “allows for a 30-percent tax credit” on installation costs for businesses. “You recoup 30 percent of the cost, dollar for dollar, in addition to LIPA’s $3.75-per-watt rebate,” which applies to systems of up to 10 kilowatts. Amaden-Gay’s rebate totaled $35,000; the tax credit, $8,500.

And who better than a group of insurance professionals to appreciate the tax write-off associated with the depreciation on such a capital investment? “You can depreciate the entire system in the first year,” Mr. Clejan said, here saving Amaden-Gay another $8,500, further winnowing the system’s initial price.

“With the return on the investment, it will take less than five years to recoup the cost,” Mr. Clejan continued, what with LIPA’s rates, commercial and residential, headed in only one direction — up more than 20 percent in a year for his client, he noted, to 22 cents per kilowatt hour.

Other numbers were on display on Monday. Two small inverters the size of medicine cabinets are now tucked away upstairs in the Amaden-Gay office maze, in a central computer room. There they take in the photovoltaic energy piped in from the roofs and turn it into alternating current to be soaked up by the building, and they constantly blink with status reports. Between midday Friday and midday Monday, 123 kilowatt hours had been produced.

A former manager of a Manhattan real estate investment firm and quick with numbers, Mr. Clejan figured on the fly: “That’s 40 kilowatt hours per day, 1,200 kilowatt hours in a month, 14,000 kilowatt hours a year.” He thought a moment more. “Officially we say people can expect to save $2,000 to $3,000 a year” on their electric bills with a roughly 10-kilowatt system. “This, if you run the numbers, is showing a $2,900 savings.”

The inverters’ displays blinked again. Two hundred and forty-six pounds of greenhouse gases had been saved up to that point.

A 50-50 Motivation

“We want to do what we can for the environment,” James P. Amaden, one of Amaden-Gay’s three principals, said. He thought about a move to solar power first for his house, which he might outfit with a system next year, he said. He shifted his attention to the business because of the “compelling financials”: Commercial incentives have now outpaced those for installing a residential system. A 10-kilowatt system is enough to power a 3,000-square-foot house, but according to GreenLogic it could take 8 to 10 years for the investment to pay off.

“It’s really 50-50,” Mr. Amaden said of his motives — economic and environmental — for going solar. “These days, everything has to work out financially.”

GreenLogic will “float the money until the LIPA rebate comes back,” he said. Mr. Amaden and company paid $28,000, about 44 percent of the retail cost, up front, and then over time will recoup the tax credit and the depreciation, eventually arriving at the $11,500 net figure.

The energy company will not only design the system, Mr. Amaden said, but will help line up rebates and guide paperwork through the local bureaucracy for a building permit, which in this case was greenlighted within 24 hours.

Mr. Amaden plans to add another 1,000 square feet of solar panels on a third roof at Amaden-Gay next year, potentially making it, in his words, “a net-zero energy conservator,” self-sufficient in its power needs.

“We think of it as a rare chance to do good in the private sector,” Mr. Clejan, who has a master’s degree in environmental management, said of his new enterprise — this after his and his partner’s “stint in pure capitalism.” Mr. Albukrek until recently headed a company that supplied machinery to the textile industry.

GreenLogic is working on an 8-kilowatt residential solar unit in Montauk, has 20 proposals in the works, according to the entrepreneurs, and will next help to turn Quail Hill Farm in Amagansett into a “zero-energy farm” powered by the sun, its tractors by vegetable waste.

“We’re optimistic that the Hamptons will be the next green corner of the world,” Mr. Clejan said.