3.2 New Envelope Requirements for 2019

The 2019 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.

 

-    

MANDATORY

§150.0

-     Mandatory minimum wall U-factor decreased to 0.071 for 2x6 or larger framing (or R-20 for wood framed walls).

-     Mandatory minimum wall insulation for masonry walls must follow the requirements of Table 150.1-A or 150.1-B.

PRESCRIPTIVE

§150.1

-     A separate prescriptive table for multifamily (Table 150.1-B).

-     Prescriptive roof insulation level increased to R-19 for Option B, below deck insulation (except multifamily homes in Climate Zones 10 and 16) between the roof rafters.

-     Prescriptive framed exterior wall U-factor decreased to 0.048 for single-family homes (except in Climate Zones 6 and 7).

-     Prescriptive mass wall U-factor increased to 0.077 for mass walls with interior insulation.

-     Prescriptive fenestration U-factor decreased to 0.30.

-     Prescriptive fenestration SHGC decreased to 0.23.

-     Prescriptive requirement for opaque exterior doors to have a maximum U-factor of 0.20. When 25% or more of the door opening is glazed, the door is treated as fenestration and must meet fenestration U-factor and SHGC requirements.

-     Prescriptive requirement for quality insulation installation (QII) (except multifamily homes in Climate Zone 7).