A Master Plan to Keep an Upper West Side Co-op Cool

For years, the residents of 157 West 79th Street made it through the long, hot summers with air-conditioning units perched in their windows. While residents at nearby buildings were installing through-wall air-conditioning, such systems seemed impossibly difficult at the 50-unit co-op on 79th Street, which was built in 1911. 

“Every so often the question of the through-the-wall air-conditioning would come up, and the answer was always ‘You can't do it,’” says M. Franklin Boyd, president of the co-op board. “The task seemed daunting to the point of being insurmountable.” 

But earlier this year, the board paid $3,500 to RAND Engineering & Architecture to lay out options that might work. The first step was to confirm that the century-old building’s electrical wiring could supply enough power without major changes. It could. 

Air-conditioning units typically have two parts: an “air handler” that cools the air in a living space; and a condenser that vents heat to the outside. Compact window units fit both parts into a single metal box. Larger air-conditioning systems often split air handlers, located in living spaces, from the condenser. 

One of the options RAND identified would have located condensers on the rooftop and in the courtyard. New ductwork would have to be cut through the building, from the ground floor to the roof, for pipes to carry refrigerant between the condensers and the air handlers inside apartments. That would require the whole building to pay for the ducts and pipes before the first air handler could be installed in an individual apartment. “We did get some pushback from residents who were not keen to spend the money and believed no one will ever do it,” says Boyd. 

A much simpler solution required workers to cut through the exterior wall of the apartment unit to allow a condenser to release its heat to the outdoors. Since the 12-story building is located in the Upper West Side-Central Park West Historic District, any changes to the exterior of the building need to be approved by the Landmarks Preservation Commission. Here, the co-op was in luck. “The building is shaped like a ‘T,’” explains Jefferson Zamora, a project engineer with RAND. “Each unit had some space on the back or side exterior wall.” Since the exterior modifications would not be visible from the street, the plan was approved. 

It cost $14,000 to create a master plan and get it through the city’s approval process. “The cost was funded through our reserves, and has now been recouped by the fees collected from those residents who have taken advantage of the new option,” says Boyd. 

The owners of four apartments have already used the master plan to create new air-conditioning systems at their own expense, ranging in cost from $10,000 to $15,000. Two shareholders chose relatively simple systems that squeeze air handlers and condensers together into a “package terminal air-conditioning” unit (PTAC), often neatly tucked into the wall beneath a window. Two other shareholders chose more expensive systems that split the condenser, set in a wall, and the air handler, often located in a closet, which pushes cool air through vents into multiple rooms. 

What did Boyd and her fellow board members learn when they met this “insurmountable” challenge? “I'd tell any board considering this to first figure out whether there is enough support in the building to justify the project,” she says. “No matter what, installation and Department of Buildings filings will be expensive, so you need people who are willing to spend several thousand, at a minimum, to install units in their homes. Finally, there should be one point person who spearheads the project. I would recommend someone with a flexible schedule who can meet with the engineers onsite during the day, walk the building, and follow up on all the myriad details.” 

With evident satisfaction, she adds, “Now everyone can answer ‘yes’ when asked by a potential purchaser if we allow through-the-wall AC.”