Clinton Hill Co-Op's Energy Efficiency Upgrades Slash Gas Use by 50%

Multiple energy efficiency upgrades over several years at the Clinton Hill Cooperative, a huge 1,221-unit, 12-building complex in Brooklyn, are delivering big results. At a cost of close to $10 million, the co-op has slashed its gas use by 50% since 2017 and is compliant with Local Law 97 until 2029. What’s more, the work — from steam trap and window replacements to smart sensors and radiator covers — was paid out of the co-op’s capital reserves without the need for an assessment. “We have a 5% flip tax, which has been critical to giving us the reserves to undertake these kinds of projects without an additional expense to residents,” says board president Alyssa Alpine. 

Split into north and south campuses, Clinton Hill Co-op has a metrosteam system, a heating design installed in some campus-style post-war apartment buildings. Steam traps in the pipework hold steam in the radiators until the heat is released. When steam traps fail to work properly, the system often burns more fuel than necessary and also leads to uneven heating, because steam will reach some apartments but not others. This was an issue at the co-op, which replaced the traps throughout the complex several years ago. In addition, a $5 million window replacement project was undertaken to prevent heat loss from apartments. However, this weatherization had another effect: “It was even hotter in apartments because the windows weren’t leaking,” says architect and board director Lee Devore. 

The board’s solution was to install more than 4,000 custom smart radiator covers, known as Cozys. These metal radiator enclosures, designed by manufacturing firm Kelvin, trap heat and release it based on individual temperature settings in each unit. “New windows plus Cozys work really well together,” says Matthew Isaacs, Kelvin’s vice president of business development. “The Cozys do a good job at not overeating the room,” he says. The covers contain an interior duct and fan and have been installed in about 96% of the co-op’s apartments at a cost of around $2.4 million. 

More recently, a system of wireless indoor heat controls and sensors developed by the firm Runwise are also giving the gas-fired boiler more accurate data, helping it run fewer heating cycles. Runwise is also able to adjust valve controls, which dictate how hard the boiler needs to run, helping it operate more efficiently. The company estimates the technology generated $96,667 in savings last year. “We are able to modulate those valves in a much more efficient way that takes advantage of all the prior weatherization work,” says Runwise co-founder, Mike Cook.

Other improvements at Clinton Hill include pipe insulation, insulated jackets for the boilers to reduce heat loss, switching common area lights to LEDs, and laundry room upgrades that include tweaking the default wash setting to cold. Another significant upgrade begun in 2022 and completed this year has been retro-commissioning a 17-year old combined heat and power (CHP) system on the north campus. In a CHP system, a turbine produces electricity and the heat generated from the process is turned into steam for heating and hot water. However, at Clinton Hill, it was never set up to run at peak efficiency. “We’ve retro commissioned it so we don’t have to run boilers in the non-heating season any more,” Devore says. 

The board has been able to take advantage of incentives from both NYSERDA and National Grid to complete the work. NYSERDA provided $818,000 for the installation of the Cozys and National Grid offered a $82,084 rebate for the Runwise controls. The co-op has also partnered with Urban Green Council and NYSERDA to provide staff training as well.

While the Clinton Hill Co-op is compliant with Local Law 97 until 2029, the board anticipates additional efficiency measures will be necessary to avoid penalties in 2030. “The next tranche of projects might be bigger and more complicated,” Devore says. For that, the board is working with engineering firms and management to figure out what will work best for their community.