Landmark Prewar Co-op Tackles Carbon Emissions with Smart Lobby Reno

For prewar buildings looking to reduce their carbon footprint, it might well be worth evaluating how much fossil fuel is being used to heat your lobby. That’s exactly what the board at 1120 Fifth Ave., a landmarked 45-unit co-op in Carnegie Hill, did, which turned out to be the first step in transforming the 1,800-square-foot lobby from a gas-guzzling space to one that’s fully electrified.

The building has a gas-fired steam boiler to provide the building’s heat. The equipment is over 40 years old, but the board, keen to put off a boiler replacement, has worked hard to make the equipment as efficient as possible. This involved fixing key components, adjusting the boiler controls, and moving a sensor to improve efficiency. “That gave us a 10% savings right away,” says William Zoha, founder and CEO of Prescient Energy and the building’s energy consultant.

However, a disproportionate heating load was still required for the lobby. “We estimated approximately 10% of the building’s annual natural gas consumption was attributable to heating the lobby,” Zoha says.

The board then decided to make a major energy-saving move. “We’ve shifted to heating and cooling the lobby with a heat pump instead of consuming so much natural gas,” says Ellen Conrad, board president and co-founder of Bedford 2030, a climate action nonprofit in Westchester.

The co-op installed a Variable Refrigerant Flow (VRF) system, consisting of an outdoor heat pump connected via refrigerant lines to a new indoor air handler with ducts leading to the lobby, which handles both heating and cooling far more efficiently than the old equipment. Rather than running at 100% all of the time, the system modifies the delivery of hot and cold air based on temperature settings. The installation cost around $100,000 and was funded through the building’s capital reserves.

Although emission penalties under Local Law 97 were not foremost on the board’s mind when the work began, Conrad says they certainly are now. Based on data from 2023, the co-op is not facing penalties until at least 2034, but the installation enables the building to qualify for beneficial electrification credits. Under the Department of Buildings guidelines, the credit allows co-op and condo boards that are early adopters of electrification to bank the accumulated carbon savings and apply them to future compliance years.

The building’s super, Martin Pjetri, was a key player in the co-op’s efficiency efforts, working with Zoha to optimize the boiler system and enthusiastically supporting the heat pump installation. “My advice to other boards is to embrace new technologies that can reduce carbon emissions,” he says. At some point in the future, the board will need to confront the question of what to do with the aging boiler.

In the meantime, to preserve heat in the lobby, Pjetri is working to reduce what’s called the stack effect, where warm air rises and affects air pressure throughout the building. It can make doors difficult to open on high floors and also affect energy efficiency. “When the front doors open, cold air rushes into the space,” Conrad explains, adding that Zoha and Pjetri are exploring ways to limit heat loss. “We want the savings to be contained,” she says.