Window air conditioners and winter: how do they mix?

May 22, 2007 12:53 PM

I'm probably going to need to leave my air conditioner in the window during the '07-'08 winter, and I have a few questions about air conditioners and winter.

I live in a studio in Chicago's north Uptown. I bought my first air conditioner last summer, a Frigidaire FAC109P1A. When the weather got colder last winter, my building's superintendent was nice enough to take it down and store it in his own storage unit. However, since the weather's getting warmer, he's putting it back up this Thursday, and he's indicated that unfortunately he won't be able to store it again this coming fall.

I've bought an air conditioner heavy duty support bracket. Although we won't be able to screw the support to the window frame itself -- the frame isn't deep enough -- the superintendent is going to screw it to a piece of wood that he'll then wedge underneath the air conditioner. This will hopefully correct one sort-of-a-flaw from last year: the air conditioner wasn't quite flush with the window frame. Last summer, the outside part of the air conditioner was at a slight angle tilted toward the ground, which meant that inside, the bottom part of the A/C stuck out from the window a little bit on a diagonal towards the floor. (I'm not sure if that's clear, visually. Let me know if it's not.)

The windows are perhaps only a year or two old, and very good. With them both closed, I barely had to open the radiator last winter. Additionally, I bought some spongy weather seal material to put around the air conditioner.

I am nervous about leaving the air conditioner in the window over next winter, thanks to the extremes of Chicago winters. I have this vision of a big ol' nasty Chicago blizzard rolling into town one morning or afternoon while I'm at work, or while I'm visiting family for Christmas, and then coming home to find the apartment freezing and my cat dead of hypothermia. I realize that could well be an irrational concern, but if so the irrationality stems from not understanding how this works. I do know that many people do leave their air conditioners up and in the window during the winter, so obviously, that sort of thing doesn't usually happen ... but I don't understand why it doesn't happen.

(1) How does the way air conditioners are built prevent winter cold from entering in the apartment? Since air conditioners in the summer run outside air over freon and then vent the chilled air into the inside, what structurally prevents that outside-to-inside airflow from happening come winter?

(2) The accordion material that expands to fill the window: is that material usually strong/insulated enough to prevent outside snow, wind, and temperatures from entering the apartment? It seems like you have to have a window plus a storm window in place to stop wintry elements from coming in; how can that accordion material do the job?

Also, I'm wondering if people have opinions on, or experience with:

(3) Evidently air conditioner covers exist (such as this quilted one), and sometimes people even use garbage bags. There seems to be some debate as to whether or not it's a good idea or not: opponents say it causes condensation problems inside the unit that can damage your unit's internals; proponents seem to believe it prevents the cold from damaging your equipment. Are they good or bad, do they make a temperature difference in the apartment, and with the ones for the outside, how the heck do you apply them? Lean out the neighboring window? I'm on a first floor apartment (not ground, but one up) -- would I grab a ladder?

(4) One of the reasons I'm leaving it in the window is because I have nowhere to store it. I have a small-to-middlin' studio; I don't foresee moving into a one-bedroom anytime soon. I think if I had to store it inside the apartment, I'd buy a really big-ass plastic container from the Container Store and then maybe drape a blanket over the container or something so it could serve as a table. But any other creative ideas for air conditioner storage in a tight space? External storage is exorbitant in the city, and my landlord doesn't offer extra storage space to building residents (not to mention someone might run off with it).

(5) This air conditioner weighs more than I'm able to lift. I don't know the upper boundary of my lifting ability, but I know that I can carry 50 pounds (the weight of a box full of reams of paper) and walk 30-50 feet with it, and that that feels near my maximum. (Weight training isn't the worst of ideas, I know, but that's for another time.) I've seen stronger men than I struggle with it (probably also due to its width and breadth). If given enough notice, I'm sure one way or the other (my super, Craigslist, etc.), I could enlist enough help to move the unit, but I wonder how I might handle moving it alone in an emergency situation. I don't know what an "emergency situation" might be, but I don't like the idea of having a piece of furniture in my apartment that I can't move. Any advice on how to move stuff that's probably above your lifting limit without hurting yourself? Is there inexpensive stuff you can get from a hardware store?

posted by WCityMike to home & garden (16 comments total)

I would recommend against leaving the unit mounted during the winter, especially in Chicago. From my experience, no matter how tightly you try to seal up around the unit during install, no matter how much you "lock up" the unit for the winter, it leaks like a seive compared to the window it's "replacing".

As for lifting extra large/bulky items, while these Forearm Forklift guys won't increase the amount you can lift, they do an amazing job of turning the bulky and handleless into the easily luggable.
posted by nomisxid at 1:13 PM on May 22, 2007

(1) It doesn't -- you need a quilted insulated cover for the unit. These are widely available.

(2)No, it's not enough. Remove it and fit in some styrofoam blocking which you can cut to fit with a box cutter knife. Then use silicon caulking (tube-about $5, gun-about $5) to fill any gaps. Even better, buy a roll of insulation and stuff that in there. Cover the whole thing with a nice decorative quilt on a dowel for the duration of the winter for looks+more insulation.

(3) Re: poss. condensation damage: I wouldn't worry. It may shorten the life of the unit very marginally, but we're talking about an appliance that should work a good ten years or so anyway, so NBD. Re: installing covers: Get on a ladder.

(4) Get an actual table with a way big cloth over it, put the unit on an old blanket or towel, and slide it under there.

(5) You and another person (of any gender) should be able to lift it easily. Arrange to have at least one visitor in May and another in September.
posted by luser at 1:18 PM on May 22, 2007

In addition to the outside cover, I'd suggest buying some of the clear plastic insulation to cover the window for the winter as well (you know, the stuff you use a hairdryer on to seal). We had your exact situation, and that really did the trick with us. It'll end up ballooning out into the room a little bit, after you seal it off, but after covering it with a curtain, we didn't even notice that there was a window there all winter.
posted by thanotopsis at 1:38 PM on May 22, 2007

If you choose to take it in and make a table out of it. You can put it on a furniture dolly to make it mobile. I like the idea of bringing it in out of the weather.

I'm in Des Moines, with similar weather conditions as you. My A/C is stored in an unheated garage. I've only been able to make the units last about 5 years. After that time, the hot/cold cycles fatigue the metal and the coolant leaks out. After that I can refill it, but it only lasts for 3-6 months - never enough to make it through the next season.
posted by kc0dxh at 2:30 PM on May 22, 2007

I have an air conditioner in my window that I left there throughout last year's Wisconsin Winter. Aside from the draft created in the gap (which we solved with a towel), we've had no problems with it.
posted by drezdn at 2:42 PM on May 22, 2007

luser, re: (2) — I rent. I assume the silicon caulking you're referring to would be permanent and thus inadvisable for something I don't own, right?

Re: (5) — I do understand that two people could handle this thing easily. I'm just wondering how, if I leave it in for the winter, I might move it myself quickly if I had to (inclement weather conditions, etc.) ... or whether the answer is simply that, "If you can't bench 100, then, no, you can't move it yourself in a hurry." (Although I suppose in such a situation I might canvas my neighbors — who are unfortunately strangers, the mood in the building seems to be to keep to one's self ... )
posted by WCityMike at 2:47 PM on May 22, 2007

FWIW, most window air conditioners don't draw outside air into the cooled space, they draw inside air through a filter in the bottom half of the unit and exhaust the cold air through the vents at the top. They're still drafty, though.

I once lived at a place where a combination window heater/ac was the main source of heating and cooling. Only on exceptionally cold (for Arkansas, when it got below 10F) nights did we have to break out the kerosene heater (rated for indoor use, of course!)

In Chicago, where it's windier and colder, good insulation will be a must, but the unit itself will be fine.

The accordion material will stop precipitation from entering, but will not do a good job of keeping out the cold. Better than an open window, sure, but hardly of any insulating value beyond that.
posted by wierdo at 2:54 PM on May 22, 2007

"Last summer, the outside part of the air conditioner was at a slight angle tilted toward the ground, which meant that inside, the bottom part of the A/C stuck out from the window a little bit on a diagonal towards the floor. (I'm not sure if that's clear, visually. Let me know if it's not.)"

Window A/Cs need a slight tilt to the rear in order to drain condensate to the rear.

Condensation caused by a cover isn't really a problem except for possible finish damage unless you block the drain.

A window a/c has the insulation value of a flat piece of tin at best. I'd remove it if at all possible.

WCityMike writes "I assume the silicon caulking you're referring to would be permanent and thus inadvisable for something I don't own, right?"

You can by removable caulking, one brand name around here is DraftStop.
posted by Mitheral at 2:57 PM on May 22, 2007

i lived in new york city and left my unit in the window all winter. it was fine. there was a little bit of a draft that i fixed by stuffing foam into the cracks (you could easily cannibalize a cheap egg-crate mattress for this and sealing with duct tape. i covered it with a quilted cover made for the purpose. not the prettiest option, but i just hung a curtain over the unit.

you could further insulate by cutting plywood to cover the thin plastic side pieces. you could even back the plywood with foam.
posted by thinkingwoman at 3:00 PM on May 22, 2007

how important is your window to you?
Could you just get a big piece of 1" rigid foam insulation and cover the whole freggin' window. (you can get it at any building supply store) Tape around the edges and call it good. It'll insulate way better than the window alone, but also block the light, not too pretty but an option. Ya know, "get 'er done"
Second question, do you pay your heating bill? If not all this fuss might not be worth it, just turn the thermostat up.
All in all I second the exterior quilt installed any way you can and the sealing plastic that you shrink with a hair dryer.
posted by sauris at 3:28 PM on May 22, 2007

do you pay your heating bill

Radiator heat — unfortunately, no thermostat.
posted by WCityMike at 5:37 PM on May 22, 2007

I heard privately from a Mefite who lives in my neighborhood. If I do decide to not leave it in the window, it looks like this bin would hold it, measurement-wise at least.
posted by WCityMike at 9:09 PM on May 22, 2007

All things considered, I'd probably leave it in the window. Sealing it in there for the winter may well be easier than storing it.

First, you'll need to extend the "storm window" alongside the AC unit. This can be done with duct tape and clear plastic sheeting (thicker is less clear, but you won't have to look at it, your neighbors will). I would get some foam insulation from the hardware store and put it between the AC and the window frame on top and bottom. The stuff marked "tight fit" should be plenty, but I don't know how well it fits down below.

Second, you'll want the accordion thing sealed up fairly tight as well. Many models come with screw holes for this purpose. (Just figure on putting some wood filler and a dab of paint on it when you move.) Or duct tape again if you're squeamish. The top and bottom of the accordion thing will leak both outside its extendable frame, and inside between its frame and the accordion material. The first you can deal with using any kind of disposable weatherstrip caulk like DraftStop or my favorite, DAPtex. It's a latex caulk that is easy to use, easy to clean up during use, and easy to remove when no longer needed. It's water-soluble, so it won't keep a leak out, but it works fine through a winter (or even two) in most storm windows. (There's also a brand of Great Stuff for "Windows & Doors", but you have to apply the whole thing in a two-hour window, and it's murder to clean up.)

Depending on the construction of the accordion thing, you may be able to put a duct-taped plastic sheet over the whole thing. That's probably better than trying to put any kind of sealer in the zig-zag rail area.

I would also repeat the foam insulation on the top and bottom of your inside window sash.

Finally, you want to put the entire window inside one of those plastic sheeting kits they sell. You can use a hair dryer to flatten and tighten the plastic to an all-but-invisible sheen. It uses double-stick tape on the window frame, which shouldn't be a problem unless you have old, cracking paint.

How has this window (or your other windows) been during last winter? If you're already getting cold Chicago drafts through it you won't see that much change. If you do a window kit like in the last step to all your windows you'll actually see a big improvement, even leaving the AC in place. Reading your post, it sounds like you're on an upper floor so you're getting a lot of radiant heat from apartments below. (This is how it works in my family's rentals, for which we pay the heat. Literally an 80/20 split for the bottom/top floors.)
posted by dhartung at 10:31 PM on May 22, 2007

You might ask mom and dad if they'd store it in the basement for you...I think they have plenty of room.
posted by rikhei at 9:41 AM on May 23, 2007

I've left my AC in the window for years. During the winter, I get insulating foam and stuff it in all the openings and cut pieces from a corrugated box to complete the seal. I also get insulating foam and cover the thin fill-out slats that go at the sides, duct-tape all areas that air in or out and push insulating foam in all open areas, including the top of the inner window.

This works quite well, and as long as you make sure you get everything out in the spring and wash the filters, it should be OK.

We have sparrows that nest under the AC. Starting at 5:00 am, they set up a huge racket -- "WORMS, mommy, WORMS -- wanna eat BUGS and WORMS."
posted by KRS at 12:58 PM on May 23, 2007

I plan on leaving my AC in the window this winter. I just moved to this city and I don't have anybody to help me lift it out of the window and I don't think it is worth it to hire someone to do it for me. I hired someone to install it.
I live on the 11th floor so it would be too difficult to cover it on the outside. Canadian winters are damp and cold so I am wondering if it you or anybody has had any problems with mould growing within the unit ( since it won't be turned on until summer). I plan on covering it from the inside of my apartment so that is about my only concern. Next time I am getting a portable AC so i won't have this problem anymore.
posted by canjann at 6:25 PM on September 22, 2007