[Kripster]

How do I confirm I really have acoustic glass? I don't find it that insulating.

[MystroX5]

Open the drivers window and feel the top sides. You should feel the laminate.

[thereef510]

it also rolls up and down a lot slower than the non laminated regular glass (although that would be hard to compare unless you had another x5 nearby).

[dream54ing]

acoustical glass have minimal insulation gain (u value/r value). they are just thicker glass to help acoustical.

[VTENGR]

Originally Posted by dream54ing

acoustical glass have minimal insulation gain (u value/r value). they are just thicker glass to help acoustical.

The ones in our vehicles have an acoustical interlayer that helps with the noise reduction. It varies slightly depending on the glass manufacturer but most offer 3db to 9db reduction in the "wind noise" frequency spectrum. The manufacturers that I saw all show their glass (standard vs acoustic) as the same thickness so in actuality the acoustic glass is same thickness but most likely slightly lighter since part of the glass volume is replaced by the acoustic interlayer.

[TurtleBoy]

Originally Posted by Kripster

How do I confirm I really have acoustic glass? I don't find it that insulating.

Look at the markings on the glass. Above the circle with the E number in it should be a Roman numeral indicating acoustic, more than likely it will be XI.

[mitch57]

Originally Posted by TurtleBoy

Look at the markings on the glass. Above the circle with the E number in it should be a Roman numeral indicating acoustic, more than likely it will be XI.

Agreed. Here's a picture of my Driver's side window with acoustic glass.

[puckybadger]

Originally Posted by mitch57

Agreed. Here's a picture of my Driver's side window with acoustic glass.

Why does mine say E4 and yours says E2 ?

[Kripster]

Originally Posted by TurtleBoy

Look at the markings on the glass. Above the circle with the E number in it should be a Roman numeral indicating acoustic, more than likely it will be XI.

Thank you! I see the XI marking.

[mitch57]

Originally Posted by puckybadger

Why does mine say E4 and yours says E2 ?

I'm not sure. Perhaps it's the difference in the window size or something. I'm sure someone will chime in with the answer.

[Caramel]

E4 = certified by Dutch authorities
E2 = certified by French authorities

[TurtleBoy]

Here is a list of the different numbers used. These are part of the European coding for auto glass.

[Paladin1]

Originally Posted by VTENGR

The ones in our vehicles have an acoustical interlayer that helps with the noise reduction. It varies slightly depending on the glass manufacturer but most offer 3db to 9db reduction in the "wind noise" frequency spectrum. The manufacturers that I saw all show their glass (standard vs acoustic) as the same thickness so in actuality the acoustic glass is same thickness but most likely slightly lighter since part of the glass volume is replaced by the acoustic interlayer.

I would also point put that decibels (dB) are measured on a logarithmic scale, so even a reduction of one dB is pretty significant. A 6dB decrease is approximately half the noise level (amplitude measured).

[Matt27]

As above, easiest way is to look for the markings or run your finger over the open edge of the window - it will feel slightly rough, almost like an unfinished surface.