Demystifying Steam: Smaller Buildings

Demystifying Steam: Smaller Buildings provides the first-ever granular estimates of the locations and prevalence of steam heat in NYC’s 53,000 small and medium multifamily buildings (and expands upon our first report on steam heat). We found that: 

  • 86 percent of multifamily properties between 5,000 and 50,000 square feet are steam heated: that’s over 700 million square feet of residential area in NYC. 

  • But these buildings are not evenly distributed across the five boroughs. Explore our interactive map to get a closer look.

Why It Matters

Forty percent of NYC’s carbon emissions come from burning fossil fuels in buildings, primarily from boilers, and we can’t achieve our long-term carbon emissions goals without retrofitting or replacing steam systems in all buildings.1 With little information about small and medium buildings (many of which will need to comply with NYC’s Local Law 97) this research takes an important first step in identifying the characteristics of these buildings. 

Proportion of NYC Multifamily Property Area
Multifamily properties larger than 5,000 SF account for 2.3B SF citywide. Over one-third of that area is found in small and medium buildings.

Predicted Number of Small and Medium Multifamily Steam Heated Properties
Learn more about the methodology and explore the map here.

The proportion of small and medium multifamily properties that are steam heated varies by borough, according to our new categorical tree-based model that predicts whether a building is steam heated or not.


1Fossil fuel combustion (natural gas and oil) in buildings accounts for 41.4 percent of carbon emissions citywide. The 2017 New York City GHG Inventory is available here

                                EXPLORE THE MAP

Demystifying Steam Cover

                                                       READ THE FIRST REPORT