View Full Version : Window AC unit install

05-16-2005, 01:23 PM
I'm trying to install an ac unit, Sharp AF-S80CX into my apartment window. It seems rather easy, but I do not have a Flat Sill/window, and Sharp is telling me that they advise to have a professional install on any non-flat sill. My windows are metal framed, and it is approx 2inches higher than the wood sill, with a 1/2" high very thin metal ridge that is where the window closes behind, which is apperntly where the ac would normally sit. I am wondering if I have to build a flat sill to go up and over the metal window frame to have the AC unit rest on or if it is normal to have an ac unit rest on that very thin rail?

05-16-2005, 02:40 PM
I have seen quite a few resting on that "thin metal ridge" for a long time. I guess it could mess up that portion of the window rail and that is why they say to have a professional install it. They dont want the blame.

roger g
05-16-2005, 03:31 PM
I don't think any window sills are flat. You can place some pieces of wood on either side of the thin metal ridge so the a/c unit bridges that part of the window or you can lay a piece of styrofoam across the sill which is a great cushion and sound deadner.


05-16-2005, 10:27 PM
I like Roger's idea of bridging the ridge or using styrofoam. That way you don't risk bending or warping the metal window frame and having your landlord keep your deposit when you end your lease.

Also, as I am sure the Sharp manual tells you, make sure the window unit is leaning at a slight angle to the outside so the moisture drains out of your apartment and not onto the floor, where it can cause water damage and problems for you and the landlord.

05-17-2005, 04:17 AM
Thanks alot for all of your replies, I tried gluing a wood block using jbweld to the outside window frame so that the ac would lean back on that but I couldn't get it to sit correctly, the seals just didnt work quite right (probably because most of the weight was still on the ridge). I think I'll try that styrofoam idea. Do you think its necessary to screw these units into the window? its a metal window frame Im not so sure that is easy for me to do since i dont have a drill.

05-17-2005, 05:49 AM
Generally, the weight of the unit is supported by chains attached at the back corners of the cover to the unit. What you put over the sill is primarily used to block air leakage, not necessarily to support the ac, though it will offer some support. I also like Roger's idea of using styrofoam, if you can find it. I've seen people use old blankets under the ac at the sill also, but I wouldn't advise that. The blanket gets wet and traps the moisture and mildews. You can buy a can of foam spray and use it, but when you remove the ac, it's going to be a mess to clean. The foam will expand and it can push up on the ac unit so you need to be careful with your application. The good thing is, you're not messing with anything structurally so you don't have to worry about constructing or de-constructing. About the hardest part of the whole installation is putting the hooks in at the top of the outside window frame to attach the chains. Sometimes you have to use a lag set and drill into brick. If you do a neat job anchoring the support chains, you're not likely to draw attention to the hooks once the ac is removed. I would assume you would remove the ac during the cold months and/or if you move.

roger g
05-17-2005, 06:16 AM
Gees!!! All those holes and screws!!!!!! In MY window!!!!! REmind me not to rent an apartment to you guys.


05-17-2005, 07:10 AM
When you say the "seals didn't work quite right", are you talking about the sliding accordion-like panels on the sides of the air conditioner?

Your wood block has to be just a tad shorter (like maybe a sixteenth of an inch) than the metal ridge.

Before you slide the panels shut, you have to stick your arm out the window at the side of the AC and lift up the back of the unit while you pull the window down over the top bracket of the AC.

If it is a heavy unit, you may want to get a helper, otherwise be prepared to yell "tally ho" to the pedestrians down below.

05-17-2005, 08:59 AM
when I put it on the metal ridge, it was a bit unstable, and wouldn't sit in place very well. The bottoms of the accordian parts were slightly misaligned, ie open, and it seems quite tough to get them aligned and stable on the ridge. I asked the handyman to take a look, but I think I'll get that piece of stryofoam anyway. Other than that the big question is how to secure it. I cant do those metal chains, the building guys would kill me and a brace is tough because its concrete on the outside sill part. And the AC unit instructions dont call for anything other than screwing in the top/bottom of the acordian into the window and using L shaped brackets to hold the bottom of the unit on the sill. I was wondering what would work best to secure it that is relatively easy to install, seeing how my wood sill is quite a bit lower (2.5") than the metal ridge of the window?

05-17-2005, 09:12 AM
It all depends on if the side vents (if there are any) will clear the wall. If the unit casing has side vents they have to be outside. Are the slide out panels held in place with a metal groved bar on the bottom of the unit? If so how high is the bar. Is the bracket on the bottom of the unit high enough to clear the metal window frame?

05-17-2005, 11:03 AM
Here you go: