NEW YORK — Jillian Lung says she’s no environmentalist. Still, she couldn’t pass up a chance to install a carpet of solar panels atop her co-op in Queens.

“At these prices, why not?” Lung said.

The government has plowed so much cash into the solar industry that it’s effectively pulled the luxury tag off of home solar systems. Combined with local incentives, buyers can save up to 90 percent on a system, whether it’s for a single-family home or a 75-unit condo in the city.

Thousands of homeowners are finding they can pay off a rooftop solar system in just a few years and then start pocketing the energy savings.

Lung, the co-op president, stumbled into solar subsidy programs last year as she priced out roof repairs. City, state and federal incentives covered nearly three-quarters of the tab for a $394,514 solar system.

The building flipped the switch on in July and already cut last month’s electric bill in half.

“This was just icing on the cake,” Lung said. “We had to change the roof anyway.”

Solar power has been getting cheaper for years. Panel prices declined 31 percent from 1998 to 2008 because of lower manufacturing and installation costs and state and local subsidies, according to a study released Wednesday by Lawrence Berkeley National Laboratory. But it still took a ramp up in federal incentives this year to bring the cost within many people’s reach.

More than half the states in the U.S. and Washington D.C. offer enough incentives to cut the costs by 40 percent or more, according to Amy Heinemann, a policy analyst at the Database of State Incentives for Renewables and Efficiency.

How much you’ll spend depends on where you live.

In New Jersey, generous state incentives can pay for more than 90 percent of a home solar system. A 5-kilowatt solar system would drop from $37,500 to about $2,625 after applying the federal tax credit, a state rebate, and a renewable energy program through the state’s largest electric utility, PSE&G. A system that size can shrink a typical home’s electricity consumption by up to 40 percent and cut an electric bill by several hundred dollars a year. The owner would recoup the cost in roughly three years.

Homeowners may never see discounts like these again. Funding in some states dwindled this year as the recession tightened government budgets.

With labor and electricity rates likely to rebound, people should do the math and determine if now is the best time to buy solar.

In some cases, it may pay to wait.

Solar technology is advancing quickly — like laptops and cell phones a decade ago — and homeowners can expect to see more powerful solar panels in the near future.