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. The prescriptive requirement of high-performance attics, which includes:
a. Insulation installed either above or below the roof deck. (This dramatically lowers the attic temperature, which can typically exceed 150o F by preventing the heat from getting into the conditioned space below and reducing HVAC load.)
b. Verified ducts in conditioned space.