I'm trying to install a window unit air conditioner, but most of the installation instructions don't seem to work with this window configuration. A little bit about the setup: The apartment is the 5th floor of a pre-war walkup building that has gone through various renovations, but none that have made it too modern. The window is about 30" wide, and is a metal frame. There are two issues that make it hard to install a window AC unit: The window sill is made out of metal, so I can't nail or screw anything into it The base of the window has a thin (about 1/4") piece of metal jutting out of the buttom that's 2" high in the interior and 1.5" high in the exterior. This means I can't rest any part of the air conditioner on the sill - it ends up just resting on that piece of metal. Most of the AC units I've looked at have brackets that get nailed into the window sill, and also require that they can sit flat against a ledge to fall into the brackets. Some examples of the instructions for the units for sale in my area are here:

Looking at my neighbors' apartments, it looks like their units have been there for decades, and some are propped up on things like phone books or 2x4s. ac unit not cooling wellI'm hoping to find a safer solution than that, so I don't accidentally drop a 50 pound AC unit 5 stories. top central air conditioner brands 2012I tinkered with it yesterday (using the LG unit), and the best I could come up with was wedging the AC in at an angle and closing the window, but that didn't seem safe or stable, and left a hole to the outside because the curtains weren't flush with the window.estimated cost of replacing air conditioning unit Is it possible to install a window air conditioner in this setup, and how would I go about doing it?

Since it sounds like it might be difficult for you to get to a lumberyard to build your own solution, you might be better off using a pre-made product. AC-Safe, makes Universal Air Conditioner Supports that might be useful in your situation. The system requires you to screw the platform into the window sill (which may or may not be possible in your situation), then simply rests against the outside of the building to support the A\C unit. I've also seen brackets that mount to the bottom of A\C unit itself, and offer support against the outside of the building (but I was unable to find an example online. I think Thermwell makes them). I have the same NYC metal windows, and I'm using a universal bracket like the other commenter posted. I drilled two small holes in the bottom of my window frame (where the sash rests when the window is closed) and screwed the bracket into the wood below. The foot of the bracket rests on the stone window ledge. It's weird that manufacturers don't provide instructions for these windows, since they seem to be pretty common in cities.

Could you use something like this? It's been working well for us!Browse other questions tagged windows air-conditioning installation or ask your own question.HomeBecoming a TenantLeasing ProcessAbout Your ApartmentPossible Maintenance IssuesRental Applications and Lease FormsFloor PlansAmenitiesPricingFrequently Asked Questions (FAQ)About UsLocal InterestsMaintenance RequestContact UsDirectionsAbout UsContact UsFloor PlansPricingAmenitiesBecoming a TenantFrequently Asked Questions (FAQ)DirectionsLeasing ProcessPossible Maintenance IssuesMaintenance RequestAbout Your ApartmentRental Applications and Lease FormsLocal Interests Before purchasing or installing window air-conditioning units, please read King & Queen Apartments’ Rules & Regulations regarding Air-Conditioning (section E, pg. 11 (2016)). Always have an assistant to help you. Never attempt to install any window air-conditioning unit alone. You risk the possibility of hurting yourself or injuring others by attempting to install the unit alone.

You also run the risk the possibility of dropping and damaging the unit, and causing damage to other property below. Checkpoints Prior to Installation Carefully remove the unit from the packaging case and follow the manufacturer’s installation instructions; DO NOT use nails, screws or brackets to secure the unit to the wall, window sill, window, window jamb or window sashes. DO NOT install or attach a support bracket(s) underneath the air-conditioner and onto to the building. If an extension cord is required, the cord must be 12-gauge electrical extension cord to handle the electrical load from the air-conditioning unit. DO NOT plug the unit in until after it is fully installed. Assemble and prepare the air-conditioning unit per the owner’s manual and installation instructions. Before installing the unit, carefully set the A/C Drip Pan (provided in apartment and located in the linen closet) onto the window sill as shown. The A/C Drip Pan is required for all window air-conditioning units at King & Queen Apartments to prevent condensation from the unit from dripping onto the building.

Install the unit in the window, making sure that the A/C Drip Pan is underneath the window air-conditioning unit and that the unit is holding the A/C Drip Pan in place. Be sure to center the unit in the middle of the window. Holding the unit, carefully pull down the window sash. The window should rest on the unit behind the window filler panel frames. Extend the side panels to both sides of the window, against each window frame. To better insulate the window, the window unit and your apartment, it is recommended that you try one or more of the following: Use the foam strips provided by the manufacturer of the air conditioning unit, or purchase foam strips to install at the window. Use rigid foam panels or side insulating panels to cover the sides of the air-conditioning unit. Use duct tape only to tape joints on the side panels for air leaks. DO NOT use duct tape to secure the side panels of the unit to the wall, window sill, window, window jamb or window sashes.

DO NOT drill holes, screw, nail or attached anything to the wall, window sill, window, window jamb, window frame or window sashes. If holes are drilled, screwed or nailed into the window sash, you will be charged the cost of replacing the damaged sash. To secure the window from being opened from the outside, insert security tension rod (provided in apartment and located in the linen closet) between the lower sash (when raised above the air-conditioning unit) and top of the inside of the window. Twist rod to adjust length. Checkpoints Prior to Removal Remove unit from window or seal it up completely on the inside after the cooling season is over; otherwise, air will leak through the unit itself. Before removing the unit from the window, be sure that it is not longer holding any water in the evaporation pan. If water is still in the pan, it could drain out into the interior of the apartment when the unit it taken out of the window. Before removing the unit, be sure to:

Unplug the power cord, Remove the wooden dowels between the lower and upper sash, Lay a towel onto the floor onto which to set the unit. While holding pressure on the unit where the window rests behind the window filler panel frames so it will not fall backwards on its own weight, carefully pull window sash up. Keeping pressure on the top of the unit, carefully pull the unit from the window, while also keeping the A/C Drip Pan from falling. Set the unit onto the towel and pull the A/C drip pan from the window sill. * If you do not feel comfortable either installing window air-conditioning units yourself, please feel free to contact one of our approved installation contractors, Shalom Improvements (757-592-1903) or Williamsburg Hammer Works at (757-969-2760), to set up a time to install and/or remove your window unit(s).  You will be charged a service fee at the time of installation and/or removal, payable directly to the contractor at time of service.