I want to silence the sound of rain drops falling on my window air conditioners by putting some kind of pad on top of them. (The sound is keeping me awake.) I also need to be very frugal right now so I'm looking into using what I have around the house. I have a roll of polyester fiberfill that I've used for quilting and crafts. It is thermally bonded spun polyester fibers. (I got this idea from someone else who said they used an air filter pad, which I think can be either spun polyester or spun fiberglass.)

I've seen a couple of "drip pads" for this purpose for sale online. But, for a couple of reasons, they won't work for me.

In considering how to make these pads, I've had a few questions for which I can't find answers on the internet. Maybe someone one on this site has the answers.

1)I had to place one AC in the direct afternoon sunlight - no choice. I know the metal housing must get very hot with the summer sun beating down on it. Does anyone know how hot the metal housing on the AC would get in, let's say, 100 F weather with the sun directly on it?

2) Does anyone know the melting or burning point (F) for spun polyester?

3) Does anyone have any opinion about a low cost material that would work better than spun polyester? (It would need to be breathable, not hold water, not break down quickly in the sun, and certainly not burn or melt and run into the AC unit.)

Thank you.

  • 2
    I think you should try earmuffs and forget about padding on top of the window unit. If it rains at lot where you are, a mat on top of the window a/c will get moldy and will hold moisture continually. This will promote corrosion of the a/c case. The traditional solution would be window awnings. Aug 26, 2018 at 10:48
  • i would try: carpet remnant, styrofoam sheet, plywood/osb sheet, even a towel pinned with magnets. you don't have to worry about heat, the outside had a fan to keep things ~outside temp.
    – dandavis
    Aug 27, 2018 at 15:54

2 Answers 2


How about a synthetic door mat? They're heavy, waterproof, and some even have bristles on the top which would soften the impact of rain.

  • plus one on this one, even though it's not my answer. Easier to find, certainly weather resistant and possibly less expensive than fiberglass mat.
    – fred_dot_u
    Aug 26, 2018 at 14:15

Do you have a source of fiberglass mat in your area? It's resistant in every aspect you've noted and not particularly expensive. It will get dirty, but anything you use will have that "problem." The stuff is available in various thicknesses, although you'd not need much thicker than 3mm or perhaps 6mm for your objective. If there's a boat manufacturer nearby or another industry which uses the stuff, you may find they would be willing to provide scraps or a scrap piece of the size required.

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