Carbon Lean Facades

With net zero and carbon neutral mandates on the near horizon, New York City has pushed the green building envelope by leveraging incentive-based programs such as Zone Green, and most recently with the Climate Mobilization Act, which will penalize buildings for non-compliance. These measures are pushing for progress ahead of slow moving code revisions and are driven in part by New York City’s 80 x 50 carbon reduction goal.

Zone Green has successfully captured the economic interest of developers to incentivize better performing building envelopes. Developers are rewarded with additional floor area ratio (FAR) based on specific over-performance criteria for the opaque and the overall facade area as compared to the energy conservation code baseline. While not foolproof in its application, the amendment specifically encourages a thicker wall build-up with increased insulation, which then reallocates the floor area within the zoning district envelope. The retrofit of (the far larger number of) existing buildings poses a different challenge, which Zone Green addresses in a similar manner by allowing an over-build into required setback and open spaces without adding to the floor area of the building. Combating the economic dilemma that thicker, more energy efficient walls count as floor area, Zone Green incentives high performance by rewarding developers with giving back the lost floor area with increased building height (and, for NYC: the taller, the better).

The building envelope plays a pivotal role in energy consumption, with heating, cooling, and lighting tying directly into how a building’s envelope is designed. Incorporating the need for high performing building envelopes into direct rewards through incentive programs successfully created a space for progress ahead of the code, as it offset the developers’ begrudging approach to initial investment cost. New York City’s next step, the Climate Mobilization Act, will mandate carbon limits for building types and will implement penalties starting 2024.