Does an over-the-range microwave count as a range hood?

Yes. Table 150.0-E names appliance-range hood combinations as vented range hoods, so a microwave that vents outdoors must meet the same capture efficiency or airflow and carry the same ratings. In recirculating mode it does not qualify.

Does a gas range need a bigger hood than an electric one?

Yes, in every size band of Table 150.0-G. Over 1,500 square feet, a gas range needs 70 percent capture efficiency or 180 cfm, against 50 percent or 110 cfm for electric.

Is a ceiling fan enough in a kitchen with no range hood?

Table 150.0-E gives 300 cfm for a kitchen exhaust fan that is not a vented hood, demand-controlled. An enclosed kitchen may use a continuous system at 5 air changes an hour instead.

Is Your Range Hood Title 24 Compliant?

A range hood complies when it vents outdoors, matches the figure in Table 150.0-G for your floor area and range fuel, and carries airflow and sound ratings. A recirculating hood does not qualify. An over-the-range microwave counts as a hood and is held to the same numbers.

Choose your report
Upload your plans
Pay securely
Permit-ready report by email

The number to match

Table 150.0-G sets one figure by floor area and fuel. Each is a capture efficiency (CE), the share of cooking emissions the hood removes under the ASTM E3087 test, or the equivalent airflow. A hood passes on either.

Over 1,500 square feet: electric 50 percent CE or 110 cfm; gas 70 percent CE or 180 cfm.
1,000 to 1,500 square feet: electric 50 percent or 110 cfm; gas 80 percent or 250 cfm.
750 to 1,000 square feet: electric 55 percent or 130 cfm; gas 85 percent or 280 cfm.
Under 750 square feet: electric 65 percent or 160 cfm; gas 85 percent or 280 cfm.

A downdraft or other kitchen exhaust fan that is not a vented hood needs 300 cfm.

Which kitchens need one

Every kitchen needs local exhaust. A kitchen open to the living area must have a demand-controlled hood. An enclosed kitchen may instead run a continuous system at 5 air changes an hour, based on kitchen volume.

Finding the rating

Airflow and sound ratings come from the Home Ventilating Institute or the Association of Home Appliance Manufacturers. Capture efficiency must come from a directory the Energy Commission approves. An ECC-Rater confirms on site that the installed model carries the rating, and the make, model and target airflow go on the installer's certificate (CF2R).

Sound and ducting

The hood must have a setting of at least 100 cfm at 3 sones or less. A hood whose lowest setting exceeds 400 cfm is exempt from the noise limit. The installer then measures the delivered airflow, or builds to Table 150.0-H with no more than 25 feet of duct and three elbows. With a capture efficiency rating, the airflow listed beside that rating is the one to meet.

Replacing a hood in an existing home

Section 150.2(b)1M sorts replacements into three cases.

A permit once required the Section 150.0(o)1G airflow or capture efficiency: the new hood meets it.
A permit required only a vented hood or fan: the new one matches that airflow or 100 cfm, whichever is greater.
Neither: Section 150.0(o)1G does not apply, though the new fan still needs airflow and sound ratings.

One caution on large hoods

ASHRAE 62.2 limits exhaust airflow where atmospherically vented gas appliances sit inside the home's pressure boundary. The compliance manual flags this for large hoods, so ask your building department before choosing one. The same rules appear in the kitchen remodel guide, and the bathroom counterpart is on bathroom exhaust fans.

Common Title 24 Questions

Frequently Asked Questions

Explore Ventilation

View all Ventilation guides → · HVAC and Water Heating · Title 24 guide