A New Way to Cut Carbon Emissions: Convert Offices Into Apartments

While many co-op and condo boards struggle to cut their buildings' carbon emissions enough to comply with Local Law 97 — which goes into effect Jan. 1, 2024 — a new report suggests that converting vacant offices into apartments would not only slash carbon emissions but also would help solve the city's chronic housing shortage.

The report by Arup, a global sustainable-development firm, found that if about 220 office buildings were converted to housing, they could produce 54% less carbon emissions by 2050. That would be a decrease of up to 11 million tons of carbon dioxide, with over half of the carbon savings coming simply from reusing existing buildings. This emission decrease is equivalent to the annual carbon output of 2.3 million passenger vehicles.

“Ninety percent of the buildings that will exist in 2050 have already been built, so if we can productively put them to use, it’s a win for the city and for the environment,” Dan Garodnick, the director of the Department of City Planning, tell The New York Times.

This fall the city proposed zoning changes known as “City of Yes for Housing Opportunity,” which could create 100,000 new apartments over the next 15 years by updating restrictive zoning rules, including the conversion of vacant offices into housing. The proposed zoning changes would allow office buildings constructed before 1990 to be converted to housing; currently, the cut-off is 1961 or 1977, depending on the neighborhood. The city estimates this change could create 20,000 homes. Office vacancy rates remain high in the wake of the pandemic-induced trend to work from home.

Other emissions cuts would come from new, more energy-efficient building facades with operable windows, which residential units must have. And about half could come from upgrades recommended by the city, such as replacing fossil fuel-powered HVAC systems with electric-powered ones, says Tess McNamara, the senior sustainability consultant at Arup who led the study.

But the cost of converting underused office buildings into residential buildings is prohibitive — unless the government provides some tax incentives. “These conversions are almost as expensive as ground-up construction,” says Robert Schiffer, the executive vice president of development at SL Green, which owns office buildings throughout New York. “In almost every case they don’t pencil out without significant government incentives.”

Several city leaders have said they intend to push for financial incentives that will support conversions when the state Legislature convenes next year. The New York City Council recently approved a package of zoning changes that cuts the red tape that has blocked many co-op and condo boards and other building owners from moving ahead with carbon-cutting retrofits.