In my apartment, it is not very loud but in the mornings I can hear occasional lawn equipment, people talking, occasional dogs barking, and cars outside the window.

I put 4 blankets over the window and that helped a lot (if I were to guess, ~10% to 20% improvement, maybe more). However, what I would like to do is seal in the 4 foot x 4 foot window hole with some sort of soundproofing material. I could then put the blankets over top that for additional benefit!

Obviously with an unlimited budget, MLV (mass loaded vinyl) like 20 or 50 layers inside the window frame and also layer the whole wall with like 100 layers. Yeah, that would do it. But my budget is not $100,000 lol. I want to spend under $100, ideally under $50. Several layers of 4 foot by 4 foot of mass loaded vinyl is too expensive, that would cost hundreds of dollars.

I thought of using this Owens Corning Foamular 250 4' x 8' x 2" from home depot, but when I googled, someone else had exactly the same idea and the response to them was that it will have almost zero effect (1 or 2 decibels, which is basically nothing).

I tried to google sound deadening foam like Auralex but was unable to find any prices.

I also considered getting some drywall/sheetrock and gluing a couple together with green glue as a "window plug".

I also considered getting some sound deadening plexiglass and sealing that in there. If that were possible I could have light also instead of a permanently dark room! It would be my favorite solution.

I also considered using weather stripping around the edges rather than caulk for an easily removable solution.

What would be the best solution for my situation?


  • Need to soundproof 4' x 4' sunk in window in apartment. I am an extremely light sleeper.
  • Solution cannot be permanent (it is an apartment). Would consider semi-permanent solutions. Can't put up a separate wall.
  • I care more about sound proofing than light transmission.
  • Desire more dramatic improvement than 4 hanging quilts and blankets can provide.
  • Budget under $50, may be able to stretch to $100. If solution is extremely amazing then maybe a little more.
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    Are you sure the window isn't serving a Code-required ventilation or escape function? Commented Oct 21, 2017 at 0:31

1 Answer 1


I recommend going to the home centers and purchasing a 4'x8'x2" sheet of expanded polystyrene. This is a very good sound deadener. Cut it to fit tightly. It costs about $20. It is also a great heat and cooling insulator. It will totally block the light. It is extremely light weight. If you take care of it, it will last forever. Easy to take in and out. Easy to store. Plug any cracks with rags and tissue paper.

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