ENERGY STAR® Qualified Windows and Patio Doors
Minimal Energy Rating Required for Each Québec Climate Zone1
| Climate zones | ER value (overall energy-saving performance) | |
| Most windows and patio doors | Picture windows | |
| B | 21 | 31 |
| C | 25 | 35 |
| D | 29 | 39 |
ABOUT NEGATIVE ER VALUES...
A negative ER value refers to an ENERGY STAR qualified product that has not been reviewed since the new CSA standards were adopted in 2004. Use the following formula to convert negative ER values: Negative ER value (pre-2004) + 33 = Approximate current ER value.
1. Source: Natural Resources Canada