Understanding Title 24 Kitchen Ventilation Requirements (2022 Code)
The Title 24 California Energy Code establishes mandatory ventilation requirements that apply to every dwelling unit in the state, including ADUs, new single-family homes, renovations, and additions. These requirements are in place to ensure that indoor air quality remains healthy and that pollutants generated during cooking are properly exhausted from the home.
To meet these requirements, homeowners and designers must provide either:
- A kitchen range hood that vents to the outdoors, or
- A properly sized ceiling- or wall-mounted exhaust fan located within the kitchen space that provides the required airflow
While the code may seem technical at first glance, its underlying purpose is straightforward: remove heat, moisture, grease, and airborne contaminants from the kitchen before they spread into the rest of the home. This guide explains each requirement in a clear and practical way so that homeowners, architects, and builders can easily understand what is needed for compliance.
1. Kitchen Range Hood Sizing Requirements (2022 Code)
- The size of the home or ADU (smaller homes typically require higher airflow because there is less overall air volume to dilute cooking emissions), and
- The type of cooking fuel used (gas cooking produces more combustion byproducts and requires stronger ventilation than electric cooking).
|
Table 4-15: Demand-Controlled Local Ventilation Exhaust Airflow Rates
(from Table 150.0-E) |
|
|---|---|
| Application | Airflow |
| Enclosed Kitchen |
• Vented range hood (including appliance-range hood combinations): capture efficiency or airflow rate specified in Table 4-14. • Other kitchen exhaust fans, including downdraft: 300 CFM (150 L/s) or a capacity of 5 ACH |
| Non-Enclosed Kitchen |
• Vented range hood (including appliance-range hood combinations): capture efficiency or airflow rate specified in Table 4-14. • Other kitchen exhaust fans, including downdraft: 300 CFM (150 L/s) |
| Bathroom | • 50 CFM (25 L/s) |
|
Table 4-14: Kitchen Range Hood Airflow Rates and Capture Efficiency Ratings
(from Table 150.0G) |
||
|---|---|---|
| Dwelling Unit Floor Area (ft²) | Hood Over Electric Range | Hood Over Gas Range |
| >1500 | 50% CE or 110 cfm | 70% CE or 180 cfm |
| >1000 – 1500 | 50% CE or 110 cfm | 80% CE or 250 cfm |
| 750 – 1000 | 55% CE or 130 cfm | 85% CE or 280 cfm |
| <750 | 65% CE or 160 cfm | 85% CE or 280 cfm |
Quick Rule of Thumb
- Smaller home → higher required CFM, because pollutants accumulate more quickly.
- Gas cooking → higher required CFM, due to increased moisture, heat, and combustion byproducts.
2. Kitchen Range Hood Sizing Tool
To simplify the process, we provide an online Kitchen Range Hood Calculator that automatically applies the Title 24 requirements. By entering just a few basic details about the home and the cooking equipment, users can quickly determine the minimum airflow needed for compliance.
This tool helps prevent oversizing or undersizing a range hood—both of which can lead to performance issues, energy inefficiency, or failed inspections.
3. Capture Efficiency — New Metric Introduced in the 2022 Code
The 2022 Title 24 Energy Code introduced an important new concept called Capture Efficiency (CE). Rather than focusing solely on airflow, capture efficiency measures how effectively the hood actually captures and removes cooking pollutants before they escape into the room.
Per the code, capture efficiency is defined as defined as:
The percentage of emitted tracer gas or pollutants that the hood successfully draws in and exhausts outdoors.
A hood with strong airflow may still perform poorly if it does not effectively capture pollutants at the source. Capture efficiency ensures that performance is assessed in a more realistic and meaningful way.
4. Certification Requirements for Range Hoods
To ensure that performance claims are accurate, a range hood used for Title 24 compliance must be listed and certified by one of the following organizations:
Hoods listed in these directories undergo standardized testing for airflow, sound rating, and overall performance. This certification step protects homeowners by ensuring that the hood they purchase meets the specifications indicated by the manufacturer and the requirements of the Energy Code.
Only hoods that appear in these certification directories are considered Title 24 compliant, regardless of what the product packaging or marketing materials may claim.
5. If No Range Hood Is Installed
In situations where a traditional range hood cannot be installed—for example, due to layout constraints or design choices—the Energy Code allows the use of an appropriately sized exhaust fan located within the kitchen and as close to the cooking appliances as practical. However, the fan must meet one of the following operating strategies:
A) Demand-Controlled Exhaust Fan
A demand-controlled fan automatically turns on when needed or can be activated manually. Requirements include:
- Minimum 300 CFM of airflow
- Activation via manual switch or an automatic control (such as occupancy or humidity sensor)
- Acceptable for both open and enclosed kitchens
This option ensures that strong ventilation is available whenever cooking activities occur.
B) Continuous Exhaust Fan (Enclosed Kitchens Only)
A continuous local exhaust system operates automatically during all occupiable hours, providing steady ventilation without requiring user action. Requirements include:
- Minimum 300 CFM, or
- An airflow rate meeting 5 ACH (Air Changes per Hour) of the kitchen volume
- Allowed only for enclosed kitchens
This approach helps maintain consistent air quality throughout the day.
6. Fan Sizing Using 5 ACH (Enclosed Kitchens)
Some enclosed kitchens, particularly in smaller homes or ADUs, may rely on the 5 ACH method to size a continuous exhaust fan.
Example Calculation
This example demonstrates how to calculate the required airflow for an enclosed kitchen using the 5 Air Changes per Hour (ACH) method. Title 24 allows this alternative sizing approach for continuous exhaust systems in enclosed kitchens. ACH represents how many times the air inside the kitchen is replaced in one hour. By calculating the kitchen’s volume and applying the 5 ACH formula, you can determine the minimum CFM required for proper ventilation.
Kitchen dimensions: 12 ft × 14 ft
Ceiling height: 10 ft
Volume: 12 × 14 × 10 = 1,680 ft³
Required airflow using 5 ACH:
1,680 ft³ × 5 ACH ÷ 60 minutes = 140 CFM**
Result
- If no range hood is installed → A 140 CFM ceiling or wall-mounted exhaust fan is required.
- If using a range hood → It must provide at least 100 CFM, be properly certified, and exhaust outdoors.
Including the example helps clarify that in many cases, the required airflow may be lower than homeowners expect—provided the kitchen is enclosed and meets certain criteria.
7. Duct Requirements
- Smooth metal ducts for efficient airflow
- Duct sizing that matches the hood outlet (commonly 6–7 inches round)
- Termination to the outdoors, either through the wall or roof
- Minimal use of sharp bends or elbows, which reduce airflow and increase noise
8. Sound Rating Requirements
Title 24 includes a maximum allowable sound rating to ensure that ventilation systems remain comfortable to use. A compliant range hood must:
- Operate at ≤ 3 sones when providing the required airflow (typically 100 CFM)
Higher sound levels are permitted only when the hood is running on boost or optional higher settings. Keeping noise levels low encourages regular use, which is essential for maintaining good indoor air quality.
9. Frequently Asked Questions
1️⃣ Can I use a recirculating (ductless) hood?
No. Recirculating hoods do not exhaust air outdoors. Because they only filter and return air to the room, they cannot remove heat, moisture, or combustion byproducts generated during cooking.
2️⃣ Do ADUs require a kitchen exhaust?
Yes — If the ADU has a cooking appliance such as a range or cooktop.
No — If the ADU only has a microwave and no other cooking equipment.
This distinction ensures that ventilation requirements scale appropriately with the actual level of cooking activity.
3️⃣ Are downdraft systems allowed?
Yes. Downdraft systems are allowed under Title 24 as long as they are vented to the outdoors and meet the minimum airflow requirements (generally 300 CFM, as required for local kitchen exhaust systems under Title 24 when used as the primary exhaust).
However, homeowners should be aware that downdraft systems often do not capture pollutants as effectively as overhead hoods, especially when using front burners or high-heat cooking methods.
4️⃣ Where does kitchen ventilation appear in the CF1R or the Title 24 report?
Kitchen ventilation is a Mandatory Measure, meaning it must be satisfied regardless of the compliance approach used. It is typically listed in the Mandatory Measures Summary of the Title 24 Report rather than in the CF1R. Please see below a screenshot of how it looks in the Mandatory Measures summary of the Title 24 report.
The Title 24 prescriptive requirements require a HERS verification of the kitchen range hood if a new or replacement kitchen range hood is installed. You can see this requirement, if triggered, on the CF1R of your Title 24 report. Please see below a screenshot of how this looks on the Title 24 report.
Code References
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We provide a Title 24 Report for Homes, ADUs, Additions, Alterations as well as Commercial projects, located anywhere in California. Reach out to us now!
