New York Co-op Explores Heat Recovery to Reduce Emissions and Costs

Capturing and reusing waste heat makes a lot of sense in theory — but how can it be done in practice? At 315 East 65th Owners Corp., a 134-unit postwar building in Lenox Hill, the board is among the first to tap into state funds to explore exactly this. The 12-story building is doing a $40,000 study — with 75% of the cost being met by NYSERDA — that will quantify all the different sources of waste heat for water, air and cooling. “We went to see where we can recapture it and how we can reuse it,” says Kyra DiFrancesco, senior energy engineer at En-Power Group, which is doing the evaluation. 

The 1960s co-op currently has an outdated steam absorption chiller for heating and cooling, and the board initially engaged En-Power to figure out how the system might be replaced. In winter, the chiller uses the gas boiler to make hot water, which is sent to the fan-coil units for heating in apartments. In summer, the chiller and cooling tower work together to send cold water to the same units for cooling. The co-op is looking at reducing emissions with high efficiency electric chillers. In addition, heat pumps for domestic hot water would allow the boiler to be switched off in summer.

Cooling tower heat recapture. The heat recovery pilot dovetails nicely with plans to replace the chiller. Although it is only in the initial data-collection phase — with temperature sensors gathering information over a six-month period — it’s clear heat recapture via the cooling tower might be the most feasible option. “We are already doing work on the chiller, and it’s a very related system,” DiFrancesco explains. The idea would be to extract heat before it goes to the cooling tower and use it to meet the building’s hot water needs in summer. 

Other elements of the co-op are also being studied for possible heat recapture, including waste water from showers and sinks. Ventilation is another area of study, with the goal of capturing heat from air lost through rooftop fans. However, in many postwar buildings like East 65th, ventilation systems are often in poor condition. “In most cases, you don’t want to be adding complexity to a system that already needs work,” DiFrancesco explains. The study will provide the board with the data needed to help them decide the best steps forward. 

Cutting costs and emissions. Heat recovery could certainly play an important role in reducing Local Law 97penalties for the co-op. Although the building is emission compliant until 2029, annual fines of around $30,000 are expected in 2030. A 10% reduction in gas use could halve that penalty. If heat recapture from the cooling tower proves the most beneficial route, the design would likely be done with heat pumps. Heat-laden water heading for the cooling tower would be redirected to the pumps to heat domestic hot water. 

Forecast. NYSERDA funding covers the initial study of the co-op’s heat recovery options. The next stage would be to apply for funds to design a heat recovery system. NYSERDA will fund up to 75% or a maximum of $80,000 to create and deliver the completed designs. As with any retrofit, one of the main challenges is finding space for the equipment. “Part of our study is going to be figuring out whether we can fit this equipment in the basement.” DiFrancesco says. For other buildings wanting to access the program, applications are open until Nov. 17, 2025 and funding is on a first-come, first-served basis.