Loud air conditioner, please hope me!
June 19, 2006 9:34 AM   Subscribe

Noisy air conditioner: Our brand-new window ac unit makes an unholy racket every 15-20 minutes or so.

I assume the racket is from the cooling bits inside the air conditioner reving up to maintain the temperature.

Our unit is sitting in the window, with towels wedged into the empty spaces between the ac and the window frame (the accordion side pieces didn't quite fit, so we haven't put them in). It might be making such a ruckus because the towels aren't stabilizing the unit enough, which would beg the question- what else can we put in the empty space to keep bugs and hot air out?

Any suggestions for dampening the noise while still enjoying the sweet cool comfort of air conditioning for the rest of the summer? My google-fu has failed me.
posted by banjo_and_the_pork to Home & Garden (11 answers total) 1 user marked this as a favorite
Is the racket from the compressor inside revving up (kind of a buzzing sound as it starts up, but fades as things get going) or is it because it's rattling inside the window frame? Rattling could be fixed by getting a snugger fit. Instead of towels you might try foam tape used for insulating windows. You can also try a piece of plywood or plexiglass that sits between the edge of the unit and the window jamb. If you bring exact measurements to the hardware store they might cut a piece of material to size.

If it's the actual machinery in the AC unit making all that noise there might be something mechanically wrong with it. If it's brand new, bring it back. A new AC should not be *that* loud. If it's more "new to you" then you might try getting advice from a repair person.
posted by drmarcj at 10:30 AM on June 19, 2006

Racket, as in a grinding noise? You might want to take off the faceplate and check to make sure that the foam insulation isn't loosened and getting stuck with the fans. I'm basing that only off of a life experience. As for creative accordian substitutes, two or three layers of trashbags have done the trick for me in the past. Duct-tape is probably the best adheisive...just overall it'll look very low budget.

If you're into really good insulation, you can bundle cheap plastic bags up in between the trashbag layers to create a nice insulatating deadspace. I only did this on an AC unit that no one could see from outside the house....it was kinda embarrasing but incredibly cheap :P
posted by samsara at 10:35 AM on June 19, 2006

Response by poster: drmarcj, it is a buzzing kind of sound that fades once things get going, but it does buzz again every so often. I should have added that this is most noticable and annoying because the ac is in our bedroom, and we only notice the noise because it's otherwise silent and we are otherwise trying to sleep. When it's not buzzing the unit is "normal" sounding.

These are both great suggestions, thanks to both of you!
posted by banjo_and_the_pork at 10:43 AM on June 19, 2006

The noise itself sounds almost like a garbage disposal. I found that if I pressed the side of the AC, the noise stopped (or at least went back to normal levels).

It's a new AC, but the act of installing required some creative modification of the accordian sections to make sure the thing sat snuggly in the window, so I'm unsure if a return is an option.

(I'm banjo's beau, btw.)
posted by robocop is bleeding at 11:13 AM on June 19, 2006

We put in a window unit at our old place -- I built a stand for it to sit on outside, then measure and cut some plywood to fill the gap left in the window. I painted it all white to match the exterior and it looked fine.

The buzzing. Yes. Our unit (heh, sorry) buzzed quite a bit when it kicked on for a few months but mysteriously stopped after that. A breaking in period? I did yell at it a few times in tired irritation, maybe I scared it quiet.
posted by empyrean at 11:14 AM on June 19, 2006

Mine buzzes too after a bit of use and only stops when I put weight on it. I had a huge book resting on the top, but now I need more (maybe a couple bricks). I also look forward to an answer here :)
posted by LukeyBoy at 1:32 PM on June 19, 2006

I had the exact same problem. Turns out that for me it was the plastic frame around the unit vibrating against the frame, and not the "guts" of the thing itself.

There are two successful and really basic/quick/dirty solutions that I found:

1. Get yourself some good gaffer's tape (duct tape, etc). Spend 15 or 20 minutes pressing on various areas of the AC to find what vibrates, and secure it/them with the tape. This worked for me for about 1 month, but was ugly. It ultimately shook things loose again. I imagine you could also try some really thin aluminum shim (tin foil). If your problem is like mine, what you're looking to do is to somehow treat plastic's contact with vibration....you can lash it to whatever's vibrating, or separate it.

2. It sounds crazy, but the ultimate solution for me was to take some 1" screws and screw them into any hole I could find in the thing. It sounds improbable, but at the time it was around 3am and I was at the end of my rope...there were these holes at various points around the thing that had no screws in them, they were just sort of sitting there. My thought at the time was "Well, what are the holes there for, anyway?" I checked as best I could to make sure that I was only screwing into the frame, and had at it. The result was both immediate and drastic, and to this day I've had very few problems that weren't solved with a turn of a screw. YMMV, obviously, but for my Goldstar AC it worked like a charm.

Good luck! There's nothing worse than a noisy monolith cranking on and off all night....
posted by nevercalm at 2:01 PM on June 19, 2006

Go to home depot or a decent hardware store and get a couple packages of air conditioner weatherseal. It's just a strip flexible foam rubberish stuff that you can push around the various edges as a seal.

I just bought a couple packages. It's by Frost King and cost maybe $1.50 or $2 per pack. Don't pay more than that. I see something similar online at lowe's for $5 a pack. That's nuts!

Here's a picture on ebay.

As for the rattle, make sure that sucker is level too (or pointing a little downward on the outside end. Otherwise, the water will flow back into your home when it rains.

And the little door on the front of mine (where you access the filter) has a nasty habit of rattling. I just stuck a good sized cotton ball in between the door and the attaching surface to stop that rattle.

Frost King has some other products too that might help if the rattle continues.
posted by bim at 5:00 PM on June 19, 2006

Response by poster: Thanks, everyone! We'll give these things a try, here's hoping we get a quiet night soon!
posted by banjo_and_the_pork at 4:17 AM on June 20, 2006

From the description of the noise, that sounds like resonance. The cure for resonance is to "change the mass", which I learned from an industrial hygienist many years back.
The way you change the mass can often be to attach it securely to some other part, which is probably why the fiendish midnight screwer had such great luck. I'd try tossing a brick on it, or a jug of water for temp, if it's the housing rattling, you should be able to tell the difference. I've had good luck with refrigerator coil housings (the metal cover around the coils in the back) by jamming a short hunk of timber between the metal and the wall.
If it's something in the innards, you could try putting a little weight on various bits and see if it shuts up. Don't put anything in there that could fall or rattle it's way into the guts and break things, obviously.
This isn't a very scientific explanation, but once you know what to look for, it's pretty easy to do the experiment.
IANAIH, don't hurt yourself.
posted by unrepentanthippie at 4:57 AM on June 20, 2006

Damnit, I knew I should've signed up on MeFi as "fiendish midnight screwer." I figured everyone would read it wrong.

Good luck, I hope this all works out...
posted by nevercalm at 5:09 AM on June 20, 2006 [1 favorite]

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