JOURNAL / WINDOWS
A window gains and loses heat mostly through its glass. So when a project aims to keep out cold, heat or street noise, the question comes up early: is double glazing enough, or is triple worth it?
How they work
Double glazing is two panes separated by a sealed cavity; triple glazing is three panes with two cavities. The cavity slows down heat and sound, so each layer adds insulation. It also changes the temperature of the inner pane: it cools down less, so it fogs up less and moisture doesn’t run down onto the wood.
What to compare
- Temperature. Double glazing is already a big step up from single; triple insulates more, especially where nights get cold.
- Noise. Each pane and cavity dampens sound; on busy streets, triple glazing is noticeable.
- Condensation. With double or triple glazing, the inner pane fogs up less.
- Weight and thickness. Triple glazing is heavier and thicker: it calls for leaves with larger sections and stronger hardware.
- Cost. Each layer adds to the price of the glass and, through its weight, to the joinery.
When we recommend each
In mild climates or on the coast, double glazing is usually enough and keeps the leaves lighter. Triple glazing makes sense when cold or noise is the main problem, or in bedrooms and studies facing the street. In doors, walkways and glass near the floor, what matters as well is safety glass: laminated or tempered.
Glass doesn’t insulate on its own
Triple glazing does little in a window that lets air through its joints. Seals and weatherstripping all around the contact between leaf and frame, and hardware that presses the leaf against them, like a tilt-and-turn’s, matter as much as the glass. Solid wood helps: it conducts far less heat than an aluminum frame.