What to know
- Compare U-factor, SHGC and Energy Rating for the complete window, not glass-only numbers.
- Confirm the exact model on Natural Resources Canada’s certified-product list before you sign.
- Many provincial programs need a registered energy assessment in addition to the product label.
The three numbers that matter
U-factor (lower is better) is heat loss through the whole assembly. Solar heat gain coefficient depends on orientation — south-facing glass can benefit from more winter sun; west-facing glass often needs less. Energy Rating combines those effects plus air leakage into a Canadian comparison score.
Certification and rebates
If you hope to claim a rebate, the model number has to appear on the certified list for the current program year. Installers sometimes quote a series that is close but not listed. Get the number in writing before a deposit.
Ready for numbers on your opening?
The estimator uses your province, window count and style to produce a range and match local companies.