Compare the actual assembly
Double glazing typically uses two panes with a sealed space; triple glazing adds another pane and cavity. Coatings, gas fills, spacers and frames all influence the finished product. Compare whole-window ratings for the exact model and dimensions under discussion rather than assuming a third pane determines every performance measure.
Match the room to the specification
Write down the reason for the upgrade. A cold seat beside the glass, afternoon overheating, street noise and a failed seal are different concerns. Discuss each elevation and how the room is used. Product ratings can help compare candidates, while the survey should establish whether air leakage or an installation defect is contributing to discomfort.
Check weight, proportions and hardware
A heavier glazing assembly can affect the frame, hardware, handling and size options. Ask whether the chosen model is offered in the desired dimensions and how it will be delivered and lifted. Compare visible glass, sash profiles and operating effort on a sample where practical. The specification should identify the actual glass package, not just say triple pane.
Understand what is being promised
Do not accept a guaranteed energy-saving percentage without the assumptions and assessment behind it. The home’s walls, air leakage, ventilation, shading and heating system also affect comfort and bills. Ask separately about sealed-glass coverage, hardware, finish and installation workmanship. Keep the labels and model numbers with the handover records.
Questions worth asking
- Are the ratings for this exact whole-window model?
- Does the glass suit the room and its orientation?
- Are the sizes, hardware and lifting plan confirmed?
- What warranty covers each component?
Further reading
Natural Resources Canada: ratings and certification ↗Source checked October 16, 2026. Current requirements and eligibility need separate project-specific verification. This guide is an original planning explanation, not a product certification or installation instruction.
