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Installing Window Air Conditioners

I’m a property manager for several Manhattan condominiums and cooperatives, and a handful of the sixth cycle Local Law 11/98 facade inspection reports filed for the buildings have been rejected by the Department of Buildings (DOB) because of what it claims are improperly installed window air conditioners. Is this a new item added to Local Law 11/98, because I’ve never seen reports rejected for this reason in previous inspection cycles? Does the DOB specify exactly what qualifies as a safely installed window air conditioner?

Although Local Laws 10/80 and 11/98 do not specifically focus on window-mounted air conditioners, the units are already covered under the existing administrative code (C26-105.3), which stipulates that exterior walls and appurtenances must be maintained in a safe condition. So the law has not changed. But, as you have noticed, the New York City Department of Buildings has been scrutinizing facade inspection reports more closely than ever before and rejecting those reports that fail to affirm the stability of window-mounted air conditioners, or have photos that show potentially unsafe units.

The reality is that window-mounted air conditioners are not considered as serious an issue as cracked bricks or loose masonry. That’s probably because there haven’t yet been any high-profile cases in New York City of air conditioners falling out of windows and injuring or killing someone. But a poorly installed air conditioner can pose as much of a danger to pedestrians as unsafe façade conditions, so property managers and boards must make sure the units at their buildings are adequately secured.

Installation Guidelines. On its web site, the DOB provides guidelines for safely installing window air conditioners ( The first step is to make sure the right-sized air conditioner is being used. It should have enough capacity to sufficiently cool the room and have a dedicated outlet with the proper amount of electrical current. The window and window frame in which the unit will be mounted should be secure and in good condition.
The air conditioner should be braced from underneath with metal brackets, mounting rails, or similar supports, or firmly fastened from inside with supporting angles. The metal brackets and angles should be attached to the exterior of the building and be strong enough to support the size and weight of the unit. Anything used to adjust the position of the air conditioner, such as shims, should be independently secured to prevent shifting caused by vibration, wind, or ice. The air conditioner should remain in place when the window is opened, or secured so that the window cannot be opened accidentally. Tilting the unit for drainage is okay as long as it isn’t at a steep angle.

Dangers come not only from an improperly secured air conditioner itself, but also from any loose objects used to support it. Bricks, wooden blocks, phone books, or (as in one case we’ve seen) videocassette tapes should never be wedged between an air conditioner and the window sill. Items such as flower pots, satellite dishes, and bird feeders should not be placed on top of the unit, either.

Aside from these general guidelines, there are factors specific to each installation that should be considered, such as the size and weight of the air conditioner, the width of the window, the depth of the windowsill, the condition of the window frame, whether the unit is installed on the top or at the bottom of the window opening, and how much of the air conditioner extends outside the window.

Establishing a building standard. Given the number of air conditioners in a multi-story building and the various problems that ensure (including gaining access to apartments, and the fact that air conditioner installations are not permanent and may change from year to year), it is impractical if not impossible for the engineer or architect conducting a Local Law 11/98 inspection to check every window-mounted unit. Rand’s protocol when conducting a typical Local Law 11/98 survey is to inspect at least one securely installed window air conditioner (which must conform to the guidelines listed above) that building management has established to be a standard for the entire building. When signing the inspection report, management is asked to confirm that all other air conditioner installations meet or exceed that standard.

Under this arrangement, building management must establish installation guidelines and procedures and make sure all residents comply. For example, management can establish a rule that window air conditioners can be installed only by someone deemed “qualified,” such as the building superintendent, a maintenance person, a technician from the store where the unit was bought, or perhaps an exterior contractor. (Currently there are no licensing requirements for installers.) Residents might be asked to complete a simple form verifying that a qualified installer put in the air conditioner.

To maintain a uniform standard of safety, it is probably not a good idea to permit residents to install window air conditioners on their own, especially on street-facing facades. Property managers will no doubt face resistance from residents and boards questioning why they need to hire an installer to put in their air conditioners when they can do it themselves and have done so in the past. The issue, however, is not unlike apartment alterations. Most residents, for example, accept that they cannot renovate their apartments without board approval. They realize that accidentally removing a load-bearing wall or rupturing a gas or plumbing line would damage not only their apartment but also their neighbors’ units and possibly the building as a whole. Similarly, without established air conditioner guidelines that require a qualified installer, some residents will no doubt hastily shove a unit in a window, close the sash, and be done with it. The more apartments in the building, the greater the risk that some of the air conditioners will not be adequately secured.

It will no doubt take an industry push to get managers, boards, and residents to comply with proper procedures for installing window air conditioners. Years ago, regulations for testing for asbestos during construction work also met with opposition from owners, managers, and contractors. Eventually, however, asbestos testing became standard operating procedure for renovation and upgrade projects, and now no one questions it as a necessary safety practice. Likewise, as more and more cooperatives and condominiums adopt rules for window air conditioners, requiring approved installations will gradually become an accepted part of building operations. Licensing standards set by a city agency to govern installer credentials would help speed up the process.

But before the industry reaches that point, boards and managers will have to remain vigilant. While individual residents will have to assume responsibility for making sure their air conditioner installation conforms to building standards, property managers and boards will still be required to monitor and enforce compliance. Such measures as marking air conditioner locations on building elevation plans and conducting spot checks should be part of the maintenance staff’s procedures. Boards, of course, are already aware that if a poorly installed unit falls and injures or kills someone, the corporation will certainly be held liable. Having established rules and guidelines in place will go a long way toward preventing a tragedy and ensuring a safe Local Law 10/80 and 11/98 status for the building.

Stephen Varone, AIA, and Peter Varsalona, PE, are principals at Rand Engineering & Architecture, which has been providing integrated engineering and architectural services to the co-op and condo community since 1987. Rand will answer your queries about renovation issues. Send questions on building repair and maintenance to

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