New York Council Is Set to Encourage Greener Buildings Eric Michael Johnson for The New York Times BrightFarms, a company that finances, builds and operates rooftop greenhouses for food retailers, recently announced the opening of the nation's largest rooftop farm in Sunset Park, Brooklyn. New York City is about to update its zoning regulations to catch up with the Bloomberg administration's environmental image and to make it easier for buildings to insulate exterior walls, install solar panels and put gardens on rooftops. With buildings accounting for 75 percent of the city's greenhouse gas emissions, city planners say, the hope is that owners will take steps to increase their structures" energy efficiency, produce their own renewable energy, put storm water to good use and, in some cases, even grow food. Mayor Michael R. Bloomberg and the City Council support the proposed new rules, which the Council is expected to approve in a vote scheduled for Monday. The zoning changes would affect building types as varied as office towers, warehouses and apartment buildings. The new regulations would encourage better insulation by allowing buildings to add up to eight inches of thickness to exterior walls without its being counted in the building's maximum footprint. Other changes would relax height limits and facade restrictions to make room for equipment like solar panels, wind turbines, awnings, green roofs, recreational decks and skylights. Solar installations, in particular, have the potential for significant growth: under the new rules, panels would be allowed on flat roofs anywhere below the parapet regardless of building height. On sloping roofs, the panels could be mounted flat. Rooftops could also accommodate boilers and other equipment that might operate more efficiently there than in the basement, officials said. But some changes apply only to certain buildings. Wind turbines could rise up to 55 inches above roofs, but only on buildings taller than 100 feet or those near the waterfront, where winds are consistent enough to generate power reliably. And the greater latitude for rooftop greenhouse installations would apply only to nonresidential buildings, including schools, that promote education or year-round food production. BrightFarms, a private company that develops greenhouses, said this month that it planned a 100,000-square-foot commercial greenhouse on the roof of a city-owned warehouse building in Sunset Park, Brooklyn. The operation is expected to yield a million pounds of produce a year. The changes in the zoning rules were based on recommendations by a task force of design and construction professionals enlisted by the city to propose ways to promote energy efficiency and other environmental improvements for buildings. Adding green features to buildings can cost thousands of dollars, and officials with the City Planning Department said they were not certain how many property owners would ultimately take advantage of the new rules. Lowering utility bills is generally the biggest incentive for older buildings to undertake energy upgrades. City planners estimate that New Yorkers spend $15 billion a year powering and heating roughly one million buildings. "Every building is going to make different decisions," said Howard Slatkin, the director of sustainability at the City Planning Department. We're creating more choices. The city offers tax incentives to property owners who install features like solar panels or green roofs. Still, Angela Pinsky, a senior vice president with the Real Estate Board of New York, the industry's trade group, said questions remained about how quickly upfront costs could be recovered through electricity savings. She said, however, that other features like green roofs were appealing to many building owners, and that the zoning changes would eliminate a "very large hurdle." Some builders suggested that the main advantage of the new rules would be saved time. Paul Freitag, the director of development for the Jonathan Rose Companies, a developer of major green projects in the city, said the new rules in many cases would eliminate the need to apply for a variance to add special features. He said it once took him 18 months to get city approval to install exterior solar shades on one building. The new rules would allow sun-control devices and awnings to project two to six feet over areas that are zoned as open space. Mr. Freitag said the more flexible approach would help property owners consider improvements "based on what they want and not on whether it's difficult to have it approved." "A lot of people will say, "We can do this differently" once they realize their options," he said. Russell Unger, the executive director of the Urban Green Council, the New York chapter of the United States Green Building Council, which confers the seal of approval, known as LEED certification, for environmentally sound buildings, said that improvements in energy efficiency were the best long-term investment for property owners looking at the bottom line. He estimated that a three-story residential building that added four inches of insulation to its exterior walls could save 10.5 percent on its yearly heating bills, reducing a utility bill of $3,575 by about $373. The City Council speaker, Christine C. Quinn, said the changes would help bring more certainty to the building industry in terms of what would be allowed. "We're giving people looking to build or rehab a building a permanent green light to make that building greener," she said.