Window-Mounted Air Conditioner Installation Guide

As far as façade inspections go, the reality is that these types of a/c units 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. Building residents should make sure the air-conditioner has enough capacity to cool the room in which it will be used. It should 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. It's a common misconception that Local Law 11 absolutely requires brackets when installing window air conditioners in buildings over six stories, but this is untrue. In fact, air conditioner brackets aren't even mentioned in LL11.

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, but also from any loose objects used to support it. Bricks, wooden blocks, or phone books should never be wedged between an air-conditioner and the windowsill. Items such as flowerpots, 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.

Building management should 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 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 façades. But boards and property managers should expect resistance from building residents who feel they can install an a/c unit themselves, especially if they've always done so in the past.

It's therefore important for boards and property managers to work together to prepare building residents for a change in the rules. Now is the time to start sending out notices explaining why air-conditioner installation procedures have to change, and organize a shareholders' meeting to address concerns. This way, building residents won't feel like they are having what they might perceive as an unnecessary and unfair change in the rules sprung on them last minute.  

In the meantime, 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 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 — not to mention ensuring a safe Local Law 11 status for the building.

Updated June 2016. For more, see our Site Map or join our Archive >>