A hermetically sealed air space primarily characterizes which type of glass construction?

Hermetically sealed air spaces are a defining feature of insulating glass units (IGUs). This construction consists of two or more glass panes separated by a space that is sealed to prevent air and moisture from entering. The air (or sometimes argon or other gases) trapped within this sealed space provides superior thermal insulation compared to single-pane glass.

The hermetic seal reduces heat transfer, making IGUs highly effective in energy conservation and climate control within buildings. These units also help in reducing condensation between the panes compared to non-sealed constructions, further enhancing their performance.

Other types of glass, such as single-pane glass, tempered glass, and laminated glass, do not incorporate hermetically sealed air spaces in their design. Single-pane glass features only one layer of glass, lacking any insulating properties from air gaps. Tempered glass is designed for increased strength and safety but does not involve air-filled spaces. Laminated glass, often used for safety and sound reduction, consists of layers of glass bonded with an interlayer but is not sealed in the same way as insulating glass units.

Thus, the characteristic of a hermetically sealed air space is exclusive to insulating glass units, underscoring their unique functionality and efficiency in construction.