Double glazing means two panes of window glass sandwiched together to create a middle buffer. "Glazing" is a specialized window term. People who repair window glass are called "glaziers."

This buffer can either be "dead air" or it can be a special gas such as argn. The idea behind double glazing is that the double panes of glass, plus the intermediate buffer zone, provide a better barrier against outside temperatures than single paned windows. Double glazing can be found with both new construction and with replacement windows. Initially created just for extreme climates, now window manufacturers are producing double glazed windows for nearly any location. Argon is a better buffer zone than air because it better inhibits passage of heat or cold into the house.

• Acoustic insulation: Double-glazing provides first-rate acoustic insulation and reduces outside noise levels.
• Added security: When glazing with 6.38 safety or intruder-proof glass, double-glazing provides excellent security for your home because its composition and design makes it very difficult to break through.
• Reducing condensation: By installing quality double-glazed windows, the problem of condensation is greatly reduced as heat is reflected back into the room and the inner pane is warmer.
• Draught-proofing: Quality double-glazed windows should boast all-round rubber seals in the frames to ensure that when closed, no draughts can get through, even in very windy areas.