Under the 2025 California Energy Code, every new kitchen and bathroom needs an exhaust fan that meets a minimum airflow and a noise limit. A vented range hood must meet a cfm or capture efficiency rating that depends on the size of the home and whether you cook with gas or electric.
These rules come from Section 150.0(o) of the Energy Code, which adopts ASHRAE Standard 62.2 with California changes, and from Chapter 4 of the CEC's Single-Family Compliance Manual. They apply to permit applications submitted on or after January 1, 2026.
Which rooms need an exhaust fan?
Section 150.0(o)1G says a local exhaust system "shall be installed in each kitchen and bathroom."
- Open (nonenclosed) kitchens must use a demand-controlled fan, one that runs when someone turns it on or a sensor does.
- Enclosed kitchens and all bathrooms can use a demand-controlled fan or a fan that runs continuously.
Demand-controlled fans need a readily accessible on-off control, or an automatic control that does not stop you from turning the fan on.
How many cfm does a range hood need?
A vented range hood must meet either the airflow or the capture efficiency (CE) in Table 150.0-G. Capture efficiency is the share of cooking pollution the hood pulls out, tested under ASTM E3087.
| Home floor area (sq ft) | Hood over electric range | Hood over gas range |
|---|---|---|
| Over 1,500 | 50% CE or 110 cfm | 70% CE or 180 cfm |
| Over 1,000 to 1,500 | 50% CE or 110 cfm | 80% CE or 250 cfm |
| 750 to 1,000 | 55% CE or 130 cfm | 85% CE or 280 cfm |
| Under 750 | 65% CE or 160 cfm | 85% CE or 280 cfm |
Two things stand out: smaller homes need more, and gas ranges need much more than electric. An ADU under 750 square feet with an electric range needs 65% CE or 160 cfm.
If you use a capture efficiency rating, it must be listed in a CEC-approved product directory, and the installed hood must move at least the airflow listed with that rating.
Recirculating hoods do not count. The manual says hoods that do not exhaust to the outside "cannot be used to meet the requirements of ASHRAE Standard 62.2."
What if the kitchen has no range hood?
Other kitchen exhaust fans, including downdraft fans, need 300 cfm on demand (Table 150.0-E). In an enclosed kitchen only, a continuous fan of 5 air changes per hour of the kitchen's volume also works (Table 150.0-F).
The manual's Example 4-14 works one out. A 12 by 14 foot kitchen with a 10 foot ceiling is 1,680 cubic feet. Five air changes per hour is 140 cfm.
How many cfm does a bathroom fan need?
| Bathroom fan type | Minimum airflow |
|---|---|
| Demand-controlled (switch or sensor) | 50 cfm |
| Continuous | 20 cfm |
How loud can the fans be?
The compliance manual lists these limits from ASHRAE 62.2:
- Whole-house ventilation fans and continuous exhaust fans: 1.0 sone or less.
- Demand-controlled exhaust fans, like a typical bath fan: 3.0 sones or less.
- Range hoods: at least one setting of 100 cfm or more at 3.0 sones or less. Hoods whose lowest setting is over 400 cfm are exempt from the noise rule.
- Remote fans mounted outside living space are exempt if there are at least 4 feet of duct between the fan and the grille.
Look up ratings in the Home Ventilating Institute (HVI) directory or the AHAM range hood listings.
How is the airflow checked?
The installer must confirm the as-installed airflow in one of two ways (Section 150.0(o)1Gv):
- Measure it with a flow hood, flow grid or similar device.
- Size the duct by the table. Install a fan and duct that meet Table 150.0-H. This only works with ducts of 25 feet or less, no more than three elbows and a properly sized exterior fitting.
The manual says an ECC rater (formerly HERS rater) must verify the kitchen hood's HVI or AHAM ratings for airflow or capture efficiency and sound. The CEC's ADU FAQ says vented range hoods in ADUs must have "their certification, airflow, and sone rating verified by an ECC rater."
Do I also need whole-house ventilation?
Usually, for a new dwelling. Section 150.0(o) also requires a whole-dwelling ventilation fan. The starting rate is Equation 150.0-B:
- Floor area x 0.03, plus 7.5 x (bedrooms + 1)
For example, a 600 square foot, one-bedroom ADU starts at 18 + 15 = 33 cfm. Detached homes, and attached homes that do not share a floor or ceiling with another unit, can reduce that rate for air leakage under the code's infiltration credit, so your report's number may be lower.
Who needs it:
- New homes and new detached ADUs. The CEC says every newly constructed dwelling must meet Section 150.0(o), "no matter the size of the ADU."
- Attached ADUs and garage-conversion ADUs. New dwelling units that are additions need it, sized on the new unit's floor area (Section 150.2(a)1Cic).
- Additions to your own home of 1,000 square feet or less, and JADUs that are additions. Exempt from the whole-house fan, but the kitchen and bath exhaust rules still apply.
The rater verifies the whole-house fan's airflow. For visit planning, see ECC (HERS) rater testing for an ADU.
Where does this show up in my Title 24 report?
The CF1R lists the required ventilation rate and which fans the rater must verify. Give your contractor the hood and fan model numbers early, so the ratings can be checked against the directory before anything is installed.
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Frequently asked questions
How many cfm does my range hood need under Title 24?
It depends on the home's floor area and whether the range is electric or gas. Table 150.0-G ranges from 110 cfm (or 50% capture efficiency) over an electric range in a home over 1,500 square feet to 280 cfm (or 85% capture efficiency) over a gas range in a home of 1,000 square feet or less.
Can I use a recirculating range hood?
Not to meet the requirement. The CEC's compliance manual says recirculating hoods that do not exhaust to the outside cannot be used to meet ASHRAE Standard 62.2.
How many cfm does a bathroom fan need?
50 cfm for a fan that runs on demand, or 20 cfm for a fan that runs continuously, under Tables 150.0-E and 150.0-F.
How loud can a bath fan or range hood be?
The CEC's manual lists 3.0 sones for demand-controlled exhaust fans and 1.0 sone for whole-house and continuous fans. A range hood must have at least one setting of 100 cfm or more at 3.0 sones or less. Hoods whose lowest setting is over 400 cfm are exempt.
Does an ECC rater check my range hood?
Yes, when your CF1R lists it. The CEC says vented range hoods in ADUs must have their certification, airflow and sone rating verified by an ECC rater. The rater also verifies whole-house ventilation airflow.
Related
Sources
- energy.ca.gov/sites/default/files/2026-07/CEC-400-2025-010-F.pdf
- energy.ca.gov/filebrowser/download/8636?fid=8636
- energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/energy-code-support-center-6/2025
- energy.ca.gov/filebrowser/download/8641?fid=8641
- hvi.org/hvi-certified-products-directory/