Author Topic: Are Impact Windows good for soundproofing home???? laminated or insulated? STC??  (Read 23889 times)


  • Guest

we have recently purchase a home and unfortunately have come to realized that the road on the other side of the lakes is noisier than we thought (better said we never expected so many pick up truck and tuned up honda Civic with loud muffler - I really don't get thes guys with loud muffler, no performance just noise....-) anyway!!!!

We are investigating the best way to block traffic noise to come into the bedrooms. The house has some pretty basic (cheap) windows with a single pane glass. We contacted windows installer and since we are in Florida they are all trying to sell us impact windows (huricane proof).

I have receive the accoustical test data from PGT industries (window manufacturer) and the Sound Transmission Class (STC). Based on our window style (and sliding door) we can either go with laminated impact window or insulated laminated impact window.

the STC for both are:
Laminated impact window 7/16 thick (3/16Glass - .090PVB - 3/16Glass) = STC of 33
Insultd Impact window 13/16 thick (2/16 Glass - 6/16 Air - 2/16 glass - .090PVB - 2/16 glass) = STC of 34

Now my questions to you are:
1 - is it a good idea to change the windows for thicker glass to reduce traffic noise?
2 - are impact windows good for soundproofing?
3 - does going from 33 to 34 STC rating make a lot of difference in sound reduction?
4 - Any other recommendation or solution out there?

this project is going to cost me $8K for the insulated 20%less for impact only i.e. STC 33.

Your help is much appreciated,

(((((Xman)))) ::) see the soundproof parentheses ;-)


  • Guest

1. Yes, absolutely.  As thick as possible.
2. Yes, because they are laminated.  Lami glass is excellent at dampening vibration and sound.
3. Nope, practically none.  If the data is available, you may want to look at the transmission loss across a wide range of frequencies, not just the STC.  The low frequency noise is what you want to kill most - look for a high TL value in the lower range.  But I doubt there's much difference.
4. You might try, in addition to new windows, a window plug.  Something that will fit snug with a good seal in you window opening.  A large airspace is what you should be aiming for.  You could achieve STC 45+ with a thick plexiglass window plug.