Net Zero for Historic Buildings

New York City is hundreds of years old and the skyline is filled with countless buildings reflecting that history. New York State is working hard to improve buildings' energy efficiency, and the question arises of what can or should be done to reduce the carbon footprints of historical buildings. Aufgang’s Director of Rehabilitation and Preservation, Iskra Petrova Ceresa, AIA shares her thoughts.

"For a building to be Net Zero, the building envelope must be very tight to minimize loss of heat and cooling. This usually means adding exterior insulation, but this can affect the building's appearance," says Iskra.

“If a building's fa?ade is iconic, renovations to achieve Net Zero must be carefully planned to preserve as many architectural details as possible. Buildings with Landmark status in New York City have very strict rules on what renovations and alterations can be done. However, Landmark status only applies to a small number of the historically significant buildings in the City. Non-Landmarked buildings are subject to substantially fewer renovation restrictions,” she said.

Adding interior insulation may be possible, but this approach may be less effective.

“In past decades,” says Iskra, “common practice was to insulate only between the framing studs. The issue with this method is that in areas where there is no insulation due to the framing, a path is created for heat and cooled air to escape the building. In recent years, building and energy codes have started requiring continuous insulation on exterior walls. Continuous insulation is placed outside of the framing members to prevent breaking up the insulation every sixteen inches, and minimizing the areas through which conditioned air can escape the building. A building with continuous insulation is much more effective in retaining a consistent interior temperature. Whether or not a building’s upgrade can include continuous insulation depends on the building design and the renovation budget,” said Iskra.

She identified design strategies that can help achieve environmental efficiency goals:

1. New insulation can be hidden behind decorative features such as molding.
2. High efficiency windows can greatly reduce building heat loss. Ideally, they should mimic the building’s original windows.

Learn more about Aufgang's sustainability mission

Aufgang has the resources required to design energy efficient renovations under the firm’s leadership team. Aufgang’s Director of Engineering, Sam LaMontanaro, PE CEM, was recently interviewed on The Civil Engineering Academy Podcast in which he discusses the challenge of electrifying buildings as required by New York State, while balancing sustainable designs and reasonable costs.

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