How does edge-gapped double-glazing improve thermal performance?

Edge-gapped double-glazing improves thermal performance primarily by creating a thermal barrier with a gap between the glass panes. This design establishes an insulating layer of air (or inert gas, in some cases) between the two panes of glass. The gap acts as a thermal break, reducing the amount of heat transfer that occurs through conduction.

When the gap is properly sized, it minimizes convection currents and helps to trap heat, effectively keeping warmer air inside during colder months and preventing heat from entering in warmer months. The effectiveness of this thermal barrier is influenced by the width of the gap and the type of gas used, as different gases can enhance insulation properties further than air alone.

The other options suggest approaches that do not fundamentally enhance the thermal barrier's effectiveness. For instance, sealing edges tightly does prevent air infiltration but does not create the necessary thermal break. Increasing air circulation between the panes could actually cause energy loss rather than conserve heat. Lastly, thicker glass materials would provide some benefits in terms of sound insulation or strength, but it does not inherently improve thermal performance as effectively as the gap creates.