Read the make-up without assuming the performance

For notation only, 6 + 22A + 6 describes two 6 mm panes separated by a 22 mm cavity. It does not identify the Low-E coating surface, gas fill, glass heat treatment, safety classification or whole-window performance. Ask for those separately rather than treating a shorthand build as a tested product.

Select Low-E around heat loss and solar gain

Low-emissivity coatings reduce radiative heat transfer. Available coatings differ in solar gain and visible light transmission. Compare U-factor, SHGC or g-value and daylight requirements for the orientation and climate. The coating position and compatibility follow the glass manufacturer specification; there is no universal rule that one climate always requires the coating on one particular pane.

Choose the cavity and edge construction together

An IGU combines panes, spacer, cavity and edge seals. Cavity width, gas fill and edge construction affect performance, but simply increasing the gap does not guarantee an improvement. Confirm the glass producer make-up, frame pocket depth, setting blocks and sealant compatibility as one assembly.

Separate laminated safety from insulation

Laminated glass bonds two or more panes through an interlayer that can retain fragments after breakage. Interlayer type, thickness, glass treatment and edge support depend on the application. A laminated pane alone does not create an insulated cavity. Where thermal and safety needs overlap, an IGU can incorporate a specified laminated pane.

Check the opening and the local safety requirements

Large doors, overhead glazing and guarding can have different requirements for glass breakage behavior and retention. Heat-treated glass and laminated glass are not interchangeable labels. Ask the project designer or local reviewer to confirm the necessary glass type, test evidence and support detail for each opening.

Send enough information for a comparable quotation

Include opening reference, glass dimensions or schedule, frame series, destination, orientation and the specified thermal/solar targets. State whether the glass is in a window, door, roof or railing. Require the quotation to identify pane thicknesses, heat treatment, coating, gas where specified, spacer and any interlayer; use the matching documentation to compare assemblies.