Skip to content
ChatProjectCodes

Earlier editions: 20222019

Chapter 4 — RESIDENTIAL MANDATORY MEASURES

4.506 Indoor Air Quality and Exhaust — 2025 California Green Building Standards Code

California Green Building Standards Code (Title 24, Part 11) · 2025 edition · updated 2026-10-19 · California

CBSC: official editions, supplements and errata

Cite as: 2025 California Green Building Standards Code (Title 24, Part 11) § 4.506 · Effective January 1, 2026 · Official source: Building Standards Commission

4.506.1 Bathroom exhaust fans. Each bathroom shall be mechanically ventilated and shall comply with the following:

  1. Fans shall be ENERGY STAR compliant and be ducted to terminate outside the building.
  2. Unless functioning as a component of a whole house ventilation system, fans must be controlled by a humidity control. a. Humidity controls shall be capable of adjustment between a relative humidity range of ≤ 50 percent to a maximum of 80 percent. A humidity control may utilize manual or automatic means of adjustment. b. A humidity control may be a separate component to the exhaust fan and is not required to be integral (i.e., built-in).

Notes:

  1. For the purposes of this section, a bathroom is a room which contains a bathtub, shower or tub/shower combination.
  2. Lighting integral to bathroom exhaust fans shall comply with the California Energy Code.

Get a plain-English answer with a citation back to this text.

Ask AI about this code
Export this section
▸Contents — California Green Building Standards Code (Title 24, Part 11)
California Green Building Standards Code (Title 24, Part 11)

GoCodebook provides public access, search, citation, multilingual explanation, and practical interpretation of legally adopted building regulations. It is not a substitute for the official ICC or California code publications.