Co-op's Extensive Retro Commissioning Reduces Energy Usage and Boosts Bottom Line

Linda Tenants Corp., a 120-unit co-op at 209-10 41st Ave. in Bayside, Queens, is reaping the rewards of extensive retro commissioning that’s taken the building from grade C to A for energy efficiency. This benchmarking leap not only makes the building emission compliant under Local Law 97 until 2030, but is also boosting the co-op’s bottom line. “Before the upgrades we used around 72,000 therms of gas annually and afterwards it was 51,000,” says John Carisle, the co-op’s secretary and resident manager. “Our usage went down 30%.”

The impressive performance of the building’s mechanical systems has been achieved through a patchwork of improvements, both large and small, over the last five years. A $1 million window and roof replacement project has been followed by upgrades to the co-op’s steam and ventilation systems, including the addition of variable frequency drives (VFDs) to the pumps and fans. 

Farsighted thinking. The 1960s building has a gas-fired boiler and a one-pipe system for heating. To improve the performance of the steam system — a process known as steam balancing — a range of upgrades were needed, including installing correctly sized air vents, adding insulating and repairing pipes, and adjusting the boiler controls. “The goal for the board was to get below the 2030 emission cap early because they understood that the longer they waited, the more expensive it was going to be,” says Darren Johnson, a senior account manager at Bright Power, the engineering consulting company brought in to oversee the improvements. 

The ventilation system had been neglected for years and construction debris was even found in the shafts. Overhauling the network and adding VFDs allowed for the frequency of motors to be adjusted without losing any capability. “We had old belt-driven fans on the roof that were not doing a good job, but now we can regulate them individually,” Carlisle says. 

Avoiding assessments. Replacing all 631 windows and adding the new roof cost around $1 million and was paid for with reserve funds. Then, in 2021 the co-op refinanced, keeping monthly payments the same but allowing it to take out equity to fund the additional upgrades. The ventilation improvements, VFDs, steam balancing and domestic hot water upgrades cost around $200,000. “None of these projects required us to assess shareholders,” Carlisle says. In addition, Con Edison provided a rebate of $55,000, amounting to around 25% of the project costs.

Bright Power continues to provide support to the building through its EnergyScoreCard software, which provides data to help drive further efficiencies. “You can’t give up ground once you’ve made an investment, because the emission caps are just going to get more stringent,” Johnson says. Dialing down energy usage has also kept the co-op’s gas and electricity bills steady despite rising costs. “Had we not done these improvements, our costs for gas alone would have gone up 44%,” Carlisle says. The EnergyScoreCard data is allowing them to consider their next steps towards Local Law 97 compliance beyond 2030.