Dissimilar glass combination

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davebe
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Joined: Mon Apr 29, 2024 10:11 pm

Dissimilar glass combination

#1 Post by davebe »

I'm replacing the window panels in my 30 year-old double pane vinyl windows, some of which have broken seals, and want to improve their sound-blocking ability. After talking with 3 different glass suppliers and researching online, I've narrowed down the combinations I'm considering. The existing window frames, which are still in good condition, have a 1" deep pocket, and consist of 2 pieces of 1/8" glass, separated by a 3/4" spacer and were originally argon filled. I'm going to replace those with a dissimilar glass panel consisting of a single 1/8" or 3/16" pane, a spacer, and a laminated pane consisting of a 1/8" glass -0.030" PVB - 1/8" glass sandwich. Depending on which company I go with, there will be 2 coats of Low/E coating (272 low/E) on either the single or the laminated pane. One supplier, who uses Milgard, recommends Argon fill; the others say low/E is sufficient. There's also the question of whether the laminate is 1/4" or 7/32"; I've been getting conflicting information on that, but just treating it as 1/4" for now.

My main question is whether to go with 1/8" or 3/16" for the single pane. I've been searching for information on dissimilar glass thicknesses, and am not sure how to weigh the benefit of the thicker 3/16" pane against the slightly smaller air gap and its more similar thickness to the laminate. The 3/16" has more mass so may block more sound, but the smaller air gap will block less, and because the 3/16" pane is closer in thickness to the 1/4" laminate, then there will be less benefit from them being dissimilar (and therefore won't block as broad a spectrum of frequencies).

So any advice as to which is more beneficial, the thicker 3/16" or the wider air gap and more dissimilar glass?

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HomeSealed
Posts: 3049
Joined: Mon Feb 15, 2010 3:46 pm
Location: Milwaukee, Madison, SE Wisconsin

Re: Dissimilar glass combination

#2 Post by HomeSealed »

Have you been given the STC and OITC ratings for each option? If so, that should give you a good indication.

Having spoken directly to the glass suppliers, what was their recommendation based on your needs/goals?

It sounds like you may not have nailed down your product choice quite yet, you may want to do so first as generally speaking manufacturers offer one option in this area and will not source custom glass.... If you have already confirmed that both options are available in your window(s) of choice, then disregard.

Regarding argon gas, it does improve thermal performance, albeit not as much as Low E. Further, unless you are located in a region that has different manufacturing processes than I'm familiar with, most companies are going to package the argon with low E as standard or at a low cost that makes it a no-brainer.

As far as the nitty-gritty detail of your question, I can see the pros and cons of each, however I I'd be surprised if that delta one way or the other is enough to realize any real-world performance difference... although I'll defer to Oberon our resident glass guru on that.

Ricknez
Posts: 169
Joined: Fri Sep 13, 2013 9:18 am
Location: southern PA, north east MD

Re: Dissimilar glass combination

#3 Post by Ricknez »

Either offset or laminated seems to be the de facto options.

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