Inside NYC’s large buildings

What types of systems heat NYC’s largest buildings?

Highlights

70 percent of large-building square footage is heated by steam systems.
Heating systems are more diverse in non-residential sectors.
Buildings with similar systems represent substantial market opportunities to scale innovative retrofit solutions.

A building’s heating system is a major driver of its energy efficiency and future retrofit options. Space heating is the single largest end use in NYC’s large buildings, accounting for over half of all site energy use. To improve energy efficiency in NYC’s largest buildings, it is essential to understand which heating distribution systems are most commonly used by each building type.

A majority of the square footage in NYC’s large buildings is heated by central steam systems where steam is produced by a boiler and piped to different areas in the building. These systems are overwhelmingly common in older buildings, and they represent a major barrier to full decarbonization because they are difficult and costly to retrofit with heat pumps. This is particularly true for 1-pipe steam systems, which use 13 percent more energy on average than other heating systems.

Hydronic (water-based) and forced air distribution systems are more common in office buildings and property types other than multifamily buildings. These systems have a more straightforward path to heat pump retrofits with current technology.

New York City’s systems data for large buildings (referred to as LL87 or audit data) offers a detailed look into the systems used for heating, cooling and other building functions. The tables below segment NYC’s large buildings into 22 different typologies, with basic characteristics for each. Combining variables like Citywide Area and Carbon Use Intensity (CUI) allows us to define the potential for decarbonization within each typology, and to identify priority sectors accordingly. Variables such as the most common heating and cooling systems can guide which retrofit solutions are applicable and potentially scalable across a given typology.