The 2016 Building Energy Efficiency Standards for residential buildings include increased efficiencies for several envelope measures, and there are improvements that have been made to better aid the designer, builder, and building official.
1. Mandatory minimum roof/ceiling construction insulation level must be at least R-22 (maximum U-factor of 0.043).
2. Increased flexibility for prescriptive compliance.
3. Increased the prescriptive roof assembly requirements to include insulation installed either above or below the roof deck. Verified ducts in conditioned space will also satisfy this requirement.