Brooklyn Condo's Ventilation Upgrades Reduce Humidity and Improve Efficiency

Stuffy corridors, dripping vents and a D grade for energy efficiency: These were just some of the problems plaguing the board at One Grand Army Plaza, in Brooklyn’s Prospect Heights. Built in 2008, the glass-clad, 15-story condo has long been uncomfortable inside during the summer. “We were getting a tremendous amount of humidity and the floors were becoming slick,” says board president Marla Maritzer. Having previously worked with En-Power Group to replace the aging chiller and partially electrify, the board turned to the engineering firm again to problem-solve the building’s inefficient ventilation.

It became clear that while the condo’s exhaust fans were oversized, the fresh air intake unit on the roof, which draws outside air through an HVAC system for ventilation, was poorly designed. “It was never really designed to fully meet the cooling loads of the building,” says Amalia Cuadra, En-Power Group’s senior director of engineering. In addition, the air intake unit’s location next to the rooftop cooling tower was problematic.

“All this humid air was leaving the cooling tower and being pulled into the fresh air unit,” Cuadra says. It created an impossible battle against indoor humidity.

With the cooling tower nearing the end of its life and requiring costly maintenance, the board decided to replace and reorganize the rooftop equipment. However, rather than replace like for like, the new equipment would be better sized to meet the needs of the building.

“The solution was holistic among the cooling power, the rooftop intake unit and the exhaust fans, so they all can be more efficient,” Cuadra says.

To fund the $1.1 million project, the board sourced money from a loan, reserves and a special assessment, which will run until the end of the year. “Operating costs have gone up and this funding strategy was the least financially impactful for residents,” says Margi Navarro, property management executive with 1Source Consultants and the project manager for the upgrades.

It turned out to be a cost-saving measure to switch out the cooling tower and air intake unit at the same time. The board didn't want to spend money on the crane twice, so replacing both on the same day made sense.

In addition to the new cooling tower and air intake unit being more efficient, newly installed exhaust fans also run at a much lower airflow volume, which is measured in cubic feet per minute (CFM). “We came down from 400 CFM to 200 CFM, so it’s a 50% saving,” Cuadra says. The upgrades are expected to generate $40,000 in annual energy savings for the condo.

Some roof preparation was required to house the new equipment. This included the removal of a redundant steel structure originally designed for window cleaning support, which had never been completed. The installation of the new equipment took place in October last year. A final element of the repairs is sealing the ductwork in the common areas. “That’s also a huge saving,” Cuadra says, because it prevents air escaping from holes and cracks.

“It’s a work in progress, so we are tweaking it as we go,” says Maritzer. She credits Navarro, who liaised with engineers and contractors, as a big part of the project’s success. “Having great management is key,” she says.