Dissimilar glass & Sound Transmission Class

Acoustic Performance

Our windows and doors include insulated glass units that are double glazed (double pane). A standard double-pane window or door consists of two panes of glass that are the same thickness.

Dissimilar Glass

Dissimilar glass consists of two panes that are different thicknesses. This is the best option to reduce sound transmission caused by outside noise. Each glass thickness reduces different frequencies of sound transmission.

Therefore, two different glass thicknesses will reduce more sound transmission than two of the same glass thickness.

Choose dissimilar glass, glass panes that are different thicknesses, to improve acoustical properties and reduce outside noise. Dissimilar glass with thicknesses 1/8 and 3/16 is recommended.

Glass Thickness

Sound Transmission Class

Sound Transmission Class (STC) is an integer rating of how effectively an interior building element attenuates, or reduces, airborne noise from one side to the other. This is used to rate various interior elements such as walls, floors, ceilings, doors, and windows.

The higher the STC rating, the better the acoustic performance. Although this is true, trying to achieve a higher STC rating can be costly. This is why choosing dissimlar glass with 1/8 and 3/16 glass is generally a good choice.

The following STC ratings feature double-glazed insulated glass units with dissimilar glass, 1/8 and 3/16. See the 'Limitations & Performance' sheet for additional STC ratings.

Item STC
Vista Sliding Window 30
Vista Plus Sliding Window 32
Vista Plus Casement Window 35
Buena Vista Sliding Door 32