Looking Forward to Monday Morning
A series of essays on business, architecture, and the business of architecture.
Park Avenue Central Air
by Daniel Frisch
Posted September 13th, 2023

This essay is a companion piece of sorts to the Luxury of Quiet, although slanting a little more towards the technical.  While the pre-war apartment buildings owe their quiet sensibility to the construction means and methods from when they were built, updated apartments often also benefit from more recently installed central air conditioning, a type of system that was not envisioned when these grand apartment buildings were constructed.  Conversely, heat is usually still delivered as it was when the buildings were built, through a low-tech and antiquated system of steam risers and radiators.  In most cases, this heat pours forth at much greater volume than necessary due to the early twentieth century need for residents to leave their windows open in winter to flood apartments with pandemic-combatting fresh air.  As for yet-to-be-invented air conditioning, early residents relied on open windows, fans, and cool drinks; and the option of relocating to mountain estates in the Adirondacks, or to the seaside resorts of Newport, the Jersey Shore, and the Hamptons, and closer to home, to hamlets like Locust Valley and Oyster Bay (Long Island’s North and South Shore towns that were the models for F. Scott Fitzgerald’s East Egg and West Egg).

Creating heat, from a physics standpoint, is straightforward (fuel + fire + water = steam).  Air conditioning, however, is more difficult, as almost all systems run on electricity, and a good amount of it.  In 1902, Willis Carrier invented and installed the first commercial air-conditioning system at the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn to cool and dehumidify the factory, and to keep the reams of paper from curling. The system was displayed to the public at the 1904 World’s Fair in St. Louis.  The auditorium and other rooms of the Missouri State Building were cooled through mechanical refrigeration; and at the very same World’s Fair, also known as the Louisiana Purchase Exposition, where the ice cream cone was invented.  By the 1970’s, most commercial buildings incorporated whole-building air-conditioning systems and multi-unit residential buildings followed suit.  Single family residential applications were much less common until the 1950’s when window air conditioners became an attainable commodity for affluent homeowners.  Where large commercial buildings relied on whole building solutions – typically chillers on the roof and air-handlers and ducted distribution systems throughout the building – most residential buildings sought post-construction solutions by which individual units would have individual control of their air-conditions, and ideally on a room-by-room basis, just like rural and suburban homes.  The solution was the same, install window air conditioners, and occasionally, through-the-wall versions (usually below a window).

The great ‘white brick’ buildings in Manhattan of the forties, fifties, and sixties introduced PTAC’s, (Package Terminal Air Conditioners) which merged heating and air conditioning systems for individual rooms in large buildings. The through-wall units sit under street or court facing windows and have both a room air conditioner and a connection to the building’s hydronic or steam risers for heat.  For those not so familiar with large apartment buildings, these PTAC units most resemble the combo heat and AC units in a Motel 6, and not surprisingly, are substandard technology for luxury apartments in the most expensive zip codes in the country.  And, when we oversee gut renovations within these white brick buildings, we replace the existing PTAC’s with exactly the same type of units.

For renovations within the pre-war buildings, we have real central air options. Together with our engineers, we design systems with through-wall condensers underneath courtyard windows, connected by line sets (piping) to air handlers within the apartments, that are, in turn, ducted to the rooms.  While this may sound complicated, the system is more straightforward than PTAC’s or individual through-wall air conditioners.  We only need to cut one hole in a building exterior to handle approximately 1500 square feet of interior space. Straightforward, yes; easy, no.

We have overseen the installation of central air conditioning within individual apartments in the pre-war creations of Rosario Candelo, Emery Roth, Delano & Aldrich, and Van Wart & Wein, and modernizing these grand apartments is anything but easy.  The process starts with design and engineering and once plans are prepared, they are submitted to the building’s managing agent, who, in turn, sends them along to the building’s architect and engineer for review, comment, and after multiple rounds of revisions, eventual approval. Once approved by the building’s team, the plans are sent through to the NYC Landmarks Preservation Commission and to the Department of Buildings for their respective approvals.  Many architects and engineers will contend that getting approvals is more difficult than designing and installing the systems.  I feel differently.  While easier with repetition, the design and install is still daunting.

Before contemplating the installation of central air, the building’s electrical service and delivery route needs to be assessed and compared with the electrical power requirements of the new system(s).  The electrical service to an individual apartment will frequently need to be increased (upgraded).  We were recently tasked with designing renovations to an estate condition apartment in the tower of one of Emory Roth’s most famous edifices fronting Central Park.  Fortunately, we knew the building’s reviewing architects and engineers, and had the opportunity to collaboratively brainstorm the routing of an additional electrical riser running the twenty-one stories between the basement and the apartment.  The new riser had to run horizontally along the basement ceiling from the electric meter room to a fire stair, and then vertically for the twenty-one stories in the space between the handrails of the turn-back stairs.  It is quite likely that our apartment owner will be the last one afforded space in the fire stair to run a new riser.  A check of the records indicates that the power upgrade was nearly as expensive as the total system installation, even with the high cost of cutting holes in the landmark’s exterior walls.  Once new power has been brought up, and after through-wall sleeves have been installed, the system install can begin.

For those unfamiliar with 1990’s technology, the systems are straightforward. A condensing unit, or two or three, go beneath windows (usually ones facing a courtyard or alley), and mated to each compressor by refrigerant supply and return piping, an air handler gets installed to blow cooled air through ducts to the various rooms.  The primary design challenge is that the condensing units need to be installed flush to the building’s exterior wall and, therefore, project meaningfully into the apartment (typically, eighteen to twenty-four inches); and the air handlers take up a two-foot by two-foot space if floor mounted, or twenty-one inches of ceiling height if ceiling-hung. And even more challenging, the ducted distribution system must snake under the heavy steel beam supporting the floor above, and without an appearance of lowering ceilings.

Once the power and spatial issues are resolved, we next need to mitigate the acoustic issues. The New York City Code has recently increased bth the energy and acoustic performance for mechanical equipment, and so much so that none of the units satisfy the requirements in an off-the-shelf ready-to-install manner.  To quiet the untis, acoustical louvers need to be installed between the condensing units and the grille that sits flush to the masonry exterior –pushing the unit further into the apartment interior and decreasing the mechanical efficiency of the condensing unit.  We have also learned that the current fans – necessary to meet energy codes – are louder and additional sound insulation needs to be installed to limit the sound transmission to the apartment interior.

So, why do we do it?  I would love to answer this with simply that we love the challenge, but while this may be true, the answer is simpler.  The benefits of central air well outweigh the difficulties (and expense).  As we replace leaky windows with modern insulated windows, to save energy and to keep out exhaust fumes and soot, modulating the interior climate has taken on even greater importance.  Today’s systems can control both temperature and humidity, and can also purify the air, removing pathogens while creating a more comfortable environment.  And all the while central air systems are quieter and more energy efficient than their through-wall, through-window, and PTAC brethren. And if an owner ever wants to sell an apartment post-renovation, central air is probably the number one component from return-on-investment standpoint.  Winner, winner, chicken dinner.