NEW YORK CITY-Mayor Michael Bloomberg on Thursday gave an update on PlaNYC, his initiative to create a greener, greater New York. One much celebrated part of the initiative calls for the phasing out of numbers 4 and 6 heating oils. One percent of buildings in the city, a PlaNYC press release says, “produce 86% of the soot pollution from buildings,” a figure that surpasses that created by all the cars and trucks here.

But some are concerned that costs for the initiative are going to be passed on to tenants. “It’s certainly a good idea over the long term,” Dan Margulies, the executive director of the Associated Builders and Owners of Greater New York, tells GlobeSt.com. “There is a significant cost in putting in a replacement burner or replacing a boiler that can range anywhere from $10,000 to $100,000.”

A city spokesman says that 10,000 buildings around the city will be affected by the new rule but that the phase out is staggered and meant to coincide with natural replacement schedules.

Number 6 heating oil would be phased out by 2015 and number 4 by 2030. Andy Darrell, the New York regional director for the Environmental Defense Fund, says that the replacement schedule is indeed in line with normal replacement schedules because of the capacity of existing equipment. “To go from number 6 oil to number 4 oil does not usually require any major capital investment,” Darrell says. “Whatever equipment is burning number 6 oil can most likely burn number 4 oil as well.”

Replacements are a tricky matter, though--with owners left to weigh the costs versus benefits of switching oils, or relying on natural gas. The iconic Beresford on Central Park West ditched heating oil altogether in favor of natural gas, according to a release on the EDF’s Web site. It all comes down to costs, the Beresford perhaps having resources that others lack. “I understand that the city believes that this is a moderate phase out,” Margulies says, “but it still costs money."

There remain questions about costs, with several sources vague on the price tag for upgrading a number 6 boiler for number 4 oil. “People say $10,000, but it's nothing near the cost of a full burner swap out,” New York City Council Member James F. Gennaro, chairman of the council’s Committee on Environmental Protection, tells GlobeSt.com. The price tag, he believes, will be well worth it. “New Yorkers will benefit in ways that I cannot do justice to with the spoken word,” he says. “The whole notion that we will be able to have pollution reduction equivalent to taking all the cars and trucks off the road in New York City with this one regulatory action is something which can’t happen soon enough.”