Tips for making window A/C units quieter?

[Klutch9]

Both of the bedrooms in our house have 5,000 BTU window AC units. From certain angles, they're quite loud when the compressor is on. I attribute this to harmonic frequency coming from the window/framing because its not audible in all points of the room, but when you hear it, it's very annoying. They're small units, so they don't require any sort of support other than the window sash, but would adding some sort of support bracket outside help redirect/change the harmonics a little? We have a larger 8,000 BTU unit in our living room, and it's the quietest of the bunch, with or without a support bracket. All units are newer, name brand and favorably reviewed, so no need to replace.

 

[AC1DD]

One thing I have found to be very effective is to wrap a piece of softer styrofoam with a plush towel and tightly fit it between the inside bottom on the unit and window sash.
Seems to quell the vibrations quite a bit. Has to be foam that will resist staying compressed.

 

[maxdustington]

Butyl tape?

 

[j_mac]

I prefer to have my bedroom blacked out, and the window with my 5000 btu Chinesium brand unit in it I have a crude but effective solution. I use a huge piece of cardboard that will cover the ENTIRE window. Measure carefully and cut out a square where the unit protrudes past the inside of the window. You can also use two separate pieces with a tape joint in the middle just above the unit to make things easier. Be sure and use common packaging tape anywhere you're taping to cardboard as it sticks to cardboard better than duct tape. Go right around the border of the cardboard with packaging tape and then, over top of that, again go around the edges with duct tape where cardboard meets the window. Duct tape connects the packaging tape coated edge of he cardboard to the window frame and metal and plastic of the AC unit. Duct tape sticks over top of the packaging tape excellent but it adheres poorly to cardboard. Duct tape loves painted metal and plastic bits.
Paint the outside facing surface with a white paint or even attach mock curtains if you don't want to offend the neighbors (before you begin.)
...An alternative I use is, in another room, I just duct tape all the edges where the unit and bellows frame meet. Duct tape to plastic and metal of AC and the other side tapes to the sash, sill and window frame. No cardboard here so no packaging tape.
Might sound crude but there isn't a better way to adapt an old house without central air.
It keeps out a great deal of the sound, and perhaps more importantly THE BUGS.
Wanna go for the extreme muffling effect? Tape over the bellows too, although I've never found that necessary.
I use really wide Duct tape that can cover wide gaps and can be torn to size for this kind of install. I have several rolls in varying widths I got from a flea market. Unknown origin, but its good stuff.
Every man HAS to learn the art of picking and choosing duct tape for its quality, and be willing to use it when its the best or only choice to make something WORK FOR YOU!

 

[Dave9]

Some A/C are louder than others. If you insist on using a noisier unit you can mount it with carpet padding/etc between it and the frame, just make sure it doesn't lie in the condensation path so it gets wet and molds.

 

[zzyzzx]

Install a mini split system in it's place.

 

[supton]

How hard is it to add a support? If it's just banging a couple pieces of scrap wood together, I'd try it. But I think foam around it, some tape, etc might also work.

 

[talest]

Put the radio on and you won't hear them (as much.)

 

[Rolla07]

Originally Posted by zzyzzx
Install a mini split system in it's place.


+1

Best investment Ive made and its much quieter and less hassle than window units

 

[PimTac]

Originally Posted by Rolla07
Originally Posted by zzyzzx
Install a mini split system in it's place.


+1

Best investment Ive made and its much quieter and less hassle than window units




I agree. If you are looking for quiet operation then this is the way to go. A good quality window unit will be quiet for the early years of operation but eventually they get noisy as parts wear or deteriorate. Splits are also very efficient and no chance of bugs coming in.

 

[SeaJay]

Mini Splits are great and the noise is outside. But $$ compared to many of the window units, if that matters.

 

[JTK]

It's going to be all experimentation for a unit of this size and configuration. They're all made cheaply and with no support other than basically being shut in a double hung window, I'd do like suggested above and try some type of padding under for it to rest on and on top of the unit for the window to close against. Making the window shaker itself quieter isn't worth the effort given it would probably be ruined in the process.

 

[Fawteen]

Mini split system or central air. You also don't have that hideous AC unit hanging off the side of the house.

 

[Andrew1972]

My useful advice is don't use the plastic side curtain that comes with AC. Instead use foam (pipe) insulation or board insulation around the chassis that contacts the window frame.