NCC 2022 Section J: what it means for your next build

NCC 2022 Section J introduced significantly tightened energy efficiency requirements for residential buildings. The headline change: whole-of-home verification, not just elemental compliance.

For window selection, this means your specification is evaluated in context with walls, roof, orientation and shading. A 1.2 U-value window will almost always pass; a 4.0 U-value window will almost always fail, no matter how insulated the walls.