Window Air Conditioners: Guidelines and Warnings

The first thing to know is that window air conditioners do fall under Local Law 11/98. While not specifically mentioned, they're covered under the existing administrative code (C26-105.3), which stipulates that exterior walls and appurtenances must be maintained in a safe condition. The Department of Buildings (DOB) scrutinizes facade inspection reports closely, and can reject reports that fail to affirm the stability of window-mounted air conditioners, or which have photos showing potentially unsafe units.

Installation Guidelines

The DOB website provides a plain-English page of guidelines for safely installing window air conditioners. Step one: Make sure the right-sized a/c is being used. It should have enough capacity to 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. While these are considered best practices, there is no requirement under Local Law 11 that buildings over six stories are absolutely required to use metal brackets.

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.

Tip: 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.

Footing Loose

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.

Aside from these guidelines, there are factors specific to each installation, such as the size and weight of the a/c, 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.

Given the number of air conditioners in a multistory building and the problems that ensue (including gaining access to apartments, and the fact that air-conditioner installations aren't 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. One protocol is to have him or her inspect at least one securely installed window a/c (which must conform to the guidelines above) that building management has established to be a standard for the building. When signing the inspection report, management is asked to confirm that all other air conditioner installations meet or exceed that standard.

Don't Do Do-It-Yourself

Under this arrangement, 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. Residents might be asked to complete a simple form verifying that a qualified installer was used.

To maintain uniform safety standards, it's not a good idea to permit residents to install window air conditioners on their own, especially on street-facing facades. Managers will doubtlessly 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. The issue, however, is not unlike apartment alterations. Most residents accept that they cannot renovate their apartments without board approval. Similarly, without established a/c 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 some air conditioners will not be adequately secured.

While individual residents will have to assume responsibility for ensuring their air-conditioner installation conforms to building standards, 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 be held liable.

Stephen Varone and Peter Varsalona are principals at Rand Engineering & Architecture.

Updated June 2016. For the complete article and more,  join our Archive >>