Overview
Triple glazing in a composite door lowers the glazed U-value from ~1.1 to ~0.8 W/m²K. Meaningful in exposed installs (coastal Cornwall, north-facing) and for noise reduction.
Symptoms
- Existing glazing feels cold to touch.
- Noticeable heat loss through the glass.
- Traffic or wind noise.
Common causes
- Double glazing at end of life or lower spec.
When to call a professional
- For upgrade quote - needs correct bead profile.
Prevention
- Specify triple on new orders in exposed positions.