Glass Thickness 3/4" 7/8" or 1"

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av
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Joined: Sun Aug 05, 2007 11:45 am

#16 Post by av »

Windows on Washington wrote: Makes very little difference in energy efficiency once you are in that range. Smaller air spaces, like those in triple pane windows, do better with Krypton filling as opposed to argon.
I have read somewhere that the sweet spot is indeed in the 3/4" to 1" range, so the energy difference may be minimal. But how about sound insulation? With everything else being the same, how much more attenuation would one get by going from 3/4" to 1"? Any rough ideas?

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Windows on Washington
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#17 Post by Windows on Washington »

av wrote:
Windows on Washington wrote: Makes very little difference in energy efficiency once you are in that range. Smaller air spaces, like those in triple pane windows, do better with Krypton filling as opposed to argon.
I have read somewhere that the sweet spot is indeed in the 3/4" to 1" range, so the energy difference may be minimal. But how about sound insulation? With everything else being the same, how much more attenuation would one get by going from 3/4" to 1"? Any rough ideas?
Sound cancellation has more to do with differing glazing thickness as they cancel differenct frequencies. Common misconception is that triple pane (single strength glass and all three panes the same thickness) windows cancel more sound than a double pane window. Simply not true. Your best bet if you are concerned is to have differing thicknesses in the two panes (or 3) or laminated glass.

Oberon
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#18 Post by Oberon »

For an IGU with a LowE2-type coating and argon gas infill, 7/16" is the optimum airspace.

For an IGU without a LowE coating or gas then 1/2" to 9/16" tends to be optimum.

An IGU begins to lose performance at airspace widths greater than 7/8". Not significant loss of performance - in fact it tends to be a very slight loss even at wider spacings - but it is a down turn nonetheless.

Adding argon to the mix makes the 7/16" more appealing because argon is most effective at about that width in an IGU and argon begins to lose some of its advatages as an insulator in wider airspaces.

Adding krypton tends to cloud the issue as well since krypton tends to be at its best in airspaces a bit below 1/4" and a krypton-filled IGU with a LowE2-type coating is very efficient at that narrower space. Like argon, krypton begins to lose effectiveness at wider spacings.

Sound insulation comes back to wider is better, however, so designing for sound takes different considerations than designing for maximum energy performance.

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