Windows and the building envelope
Windows are among the weakest thermal points in most Canadian homes. Even well-performing units transfer heat several times faster than an insulated wall section of the same area.
Upgrading from single-pane to double-pane Low-E glass typically reduces window heat loss substantially, though exact figures depend on installation quality, frame type, and orientation.
- Orientation affects solar heat gain differently by season
- Air sealing at the rough opening matters as much as the unit itself
- Thermal bridging through frames adds to overall heat flow
- Interior condensation signals insufficient surface temperature