Envelope

Related Measures

• Nonresidential Envelope

  This code change proposal includes measures designed to improve building energy performance through envelope-related updates, like requiring vestibules for certain buildings (both new construction and additions) with high-traffic main entrances in all climate zones.

• Compartmentalization and Balanced Ventilation / Indoor Air Quality (IAQ)

  This proposed measure would add a mandatory measure for all multifamily units (except garden-style units) to lower the compartmentalization tested leakage value and use supply-only or balanced ventilation as a whole dwelling unit strategy—in other words, use of exhaust-only ventilation could not be used for whole dwelling unit ventilation.

• Single Family Buried Ducts and Cathedral Ceilings – Buried Ducts is no longer being considered for the 2025 Code Cycle

  This measure proposes new prescriptive requirements in certain climate zones for higher levels of attic insulation and for ducts in the attic to be fully buried. A simplified verification approach is proposed along with updates to the value of duct burial in the compliance software. The mandatory requirement for R-4 roof deck insulation would also be exempted if ducts are buried. Additionally, this measure proposes to add a new alternative prescriptive compliance path for cathedral ceilings.

• Multifamily Envelope

  This CASE Report will focus on three measures that are grouped into the 'Envelope' category of building systems. These three measures work in conjunction to reduce the total amount of heat transfer that occurs in a building from the conditioned inside air to the outside ambient air.

• Multifamily Restructuring

  The multifamily restructuring CASE Report will propose changes to envelope and HVAC requirements that differ under 2022 Title 24, Part 6 between multifamily buildings up to three habitable stories and multifamily buildings four or more habitable stories.

• Single Family High-Performance Windows and Walls

  This measure targets the thermal performance of the building envelope and evaluates savings potential and cost-effectiveness of high-performance windows in all California Climate Zones. This measure also proposes to increase the mandatory insulation requirements for exterior walls.