According to Mr. Schneier, the state is a leader in the developing market for investors and utilities wanting to buy these credits, called Solar Renewable Energy Credits. Each credit certifies that one megawatt-hour of power has been produced by solar energy.

The credits are bought and sold in an online marketplace. New Jersey’s credits have emerged as a particularly hot property, because electric rates are comparatively high here, making each megawatt of power worth more.

“The system is complicated,” said Douglas Fenichel, a spokesman for K. Hovnanian Homes. When Hovnanian put solar technology on its list of options at its Jockey Club age-restricted development in Oceanport, he said, “We found people didn’t really understand it.”

Buyers were generally interested in sustainable construction, Mr. Fenichel said. But it was hard to explain the savings and how they would be reaped by buyers. In the end, the developers decided to make solar standard instead of optional in all 44 Jockey Club units. The development sold out six months ago.

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“It was not until the first resident stood there watching his meter going backward, generating electricity that would go back to the power company, that I think it really sunk in,” Mr. Fenichel said.

Mr. Schneier of the PulteGroup noted that buyers on a fixed income — or thinking about retiring — may be attracted to the idea of owning a solar system. “Of course, now, though, everyone is starting to think about cutting costs any way they can,” he added.

Several builders, as well as individual homeowners around the state, are moving to install solar panels on the roofs of their buildings, along with support technology to meter productivity.

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In New Brunswick, for instance, Ironstate Development is retrofitting Riverwatch Commons, an apartment building, with rooftop technology that will power lighting in common areas and the garage.

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The cost of the units has been the prevailing issue holding back more widespread use, said Michael Winka, the director of the New Jersey Board of Public Utilities Office of Clean Energy. At River Pointe, the cost to the developers of installing the standard 2.25 kilowatt unit, which at current rates would earn about $1,330 in credits per year, is about $20,000. An optional upgrade to a 3.1 kilowatt system, which would earn about $2,000 per year, would cost the buyer $10,000. Mr. Schneier said that solar equipment adds to resale value.

On the other hand, Mr. Winka said that most solar power systems start to wear out after about 10 years. In addition, both he and Mr. Schneier said that the market for energy credits could not be expected to remain strong indefinitely, as utility companies are pushing ahead with developing their own solar plants.

The reimbursement at River Pointe on a house bought right now would shape up like this, according to the PulteGroup’s calculations:

¶$6,000 to $10,000 in federal tax credits, depending on the size of the solar unit.

¶Roughly $450 in reduced energy costs the first year, depending on use and house size (floor plans range from 1,600 to 2,700 square feet). Savings would rise in proportion to rising energy costs.

¶Solar technology is exempted from property tax, saving $341 or $451 a year, depending on the size of the unit.

¶Proceeds from the sale of energy credits, $1,333 or $2,000 a year.

There are already 150 residents at River Pointe, a community of single-family houses with yards that are maintained by the homeowners’ association, a community clubhouse and other amenities. A total of 550 units are planned.

A model unit with the solar panels and technology installed is newly completed and open to house hunters.