Most kitchen range hoods should move somewhere between 300 and 600 CFM, and the right number for your kitchen comes from three things: how much heat your range puts out, how wide the hood is and how far it reaches over the burners, and how long the duct run is. A workable starting point for most homes is 100 CFM for every linear foot of range against a wall, then adjust upward for a high-output range, an island installation, or a long duct with elbows in it.
That number matters more than it looks on a spec sheet. Pick too little airflow and you’ll live with grease film on the cabinet doors above the range and a kitchen that still smells like last night’s dinner. Pick too much and you cross a threshold that requires a make-up air system, which is a mechanical addition nobody wants to discover after the cabinetry has been ordered.
What Does CFM Actually Measure on a Range Hood?
CFM stands for cubic feet per minute, and it’s the volume of air the hood’s blower can move. A 600 CFM hood can pull 600 cubic feet of air out of the room every minute at its highest setting. It’s a rating of the fan, not a promise about how much smoke actually leaves your kitchen.
That distinction matters, because the rating is measured in ideal conditions. Once the blower sits in a real duct with real bends and a real exterior cap, the air that reaches the outside is less than the label. Two hoods with the same rating can perform very differently.
Berkeley Lab researchers tested seven hoods priced from forty dollars to six hundred and fifty dollars and measured how much cooking pollution each one captured. They found capture efficiencies ranging from 15 to 98 percent, and price alone did not predict which hoods performed well. Hood shape and how far it extended over the burners mattered more than the sticker.
How Many CFM Does Your Range Hood Need?
Start with the range. For a hood against a wall, plan on roughly 100 CFM for every linear foot of range, so a 30-inch range wants about 250 CFM and a 48-inch range wants about 400. For an island hood, plan closer to 150 CFM per linear foot, because there are no side walls holding the plume in place.
Then check that against how you cook. A standard four-burner gas range sits comfortably in the 300 to 400 CFM range. A professional-style range with high-output burners or a griddle needs more, and so does a kitchen where somebody sears, fries or uses a wok regularly. Electric and induction produce less grease-laden vapor than gas, so they can sit at the lower end.
| Setup | Practical starting point | What pushes it higher |
|---|---|---|
| 30-inch electric or induction, against a wall | 250 to 300 CFM | Long duct run, frequent frying |
| 30-inch to 36-inch gas range, against a wall | 300 to 400 CFM | High-output burners, open plan |
| 36-inch to 48-inch professional-style gas range | 600 CFM and up | Griddle, wok cooking, island placement |
| Any range on an island | Add about 50 percent | No side walls to contain the plume |
One more factor decides whether the number you land on does any good: coverage. A hood that’s narrower than the range, or mounted so shallow that the front burners sit outside its footprint, loses the plume before the blower ever sees it. Whenever the plan allows, we size the hood at least as wide as the range and deep enough to sit over the front burners.
That detail changes performance more than another hundred CFM would. The same Berkeley Lab work found that when a hood doesn’t reach the front burners, simply cooking on the back burners could make the hood up to twice as effective. Geometry deserves the first conversation, not the last.
Does the Duct Run Change the Number You Need?
Yes, and it’s the factor most people skip. Every foot of duct, every elbow and every transition adds resistance the blower has to overcome, so the same hood delivers less air through a long, twisting run than through a short, straight one. Two identical kitchens on different walls can need different hoods for that reason alone.
The practical rules are simple. Keep the run short and straight. Use rigid metal duct rather than flex, because corrugated flex sheds a surprising amount of airflow to friction. Match the duct diameter the manufacturer specifies instead of squeezing a large blower into a small pipe, which throttles the hood and makes it louder at once.
This gets expensive when the range sits on an interior wall or an island. Getting a duct from there to the outside can mean routing through a joist bay, dropping a soffit, or boxing a chase through the floor above. All of it is cheaper to solve on paper, which is why hood ducting belongs in the same conversation as where the range lands in your kitchen layout.
Is a Recirculating Hood Ever the Right Answer?
Only when ducting outside is genuinely impossible. A recirculating hood pulls air through a charcoal filter and pushes it back into the room. It captures some grease and some odor, but the heat, the moisture and the combustion byproducts stay in your kitchen. It’s a fallback, not an equal option.
The Department of Energy’s Building America guidance is blunt about it. In its kitchen exhaust guidance, published at the Building America Solution Center, recirculating fans that draw air through a filter and discharge it back into the room are treated as unacceptable for kitchen exhaust. The same guidance sets 100 CFM as the minimum intermittent flow rate for a kitchen fan that does vent outside.
We do run into this in condominiums and older homes where an exterior wall is out of reach. If that’s your situation, buy the best filtration the unit offers and replace the charcoal on schedule rather than when it starts to smell. Nobody should be sold a recirculating hood as an upgrade.
What Happens If Your Hood Exceeds 400 CFM?
You trigger a make-up air requirement. A powerful hood pulls air out of a tight house faster than the house can replace it, which creates negative pressure. That can draw air backward down a chimney or a water heater flue, so the residential code requires that air removed above a threshold be replaced deliberately.
The Building America guidance states that a kitchen exhaust fan operating in excess of 400 cfm must be provided with a makeup air system that starts and runs with the hood and supplies air at an equivalent rate. In practice that means a dedicated duct bringing outside air in, a motorized damper wired to the hood, and in a Chicago-area winter, some way to temper that incoming air.
None of that argues against a strong hood. It argues for deciding early. A 600 CFM hood with make-up air planned from the start is a clean installation. The same hood specified after the mechanical rough-in turns into a change order, a rerouted duct, and sometimes a downgraded appliance.
- Decide the range first, because its burner output sets the floor for everything else.
- Confirm the shortest realistic duct path from that wall or island to the outside.
- Check whether the airflow you need crosses 400 CFM, and plan make-up air if it does.
- Size the hood at least as wide as the range and deep enough to cover the front burners.
- Pick the model last, once airflow, duct size and mounting height are settled.
Where Hood Sizing Fits Into a Kitchen Design
Ventilation is one of the few kitchen decisions that touches the appliance package, the cabinetry, the framing and the mechanical work at once. Hood height sets the cabinet above it. Duct size sets what has to be framed. The airflow target decides whether a make-up air duct joins the plan.
When we specify a hood, we work backward from three things in this order: the burner output of the range the client actually chose, the shortest duct path from that wall or island to the outside, and only then the CFM rating on the box. That order keeps the hood from forcing a change to everything around it.
It’s also why ventilation comes up early in the way we plan a kitchen remodel. A hood isn’t a finish you can swap late. It’s a mechanical component wearing a decorative cover, and the mechanical half has to be resolved while the drawings are still drawings.
Frequently Asked Questions
Is 400 CFM enough for a range hood?
For most home kitchens with a 30-inch or 36-inch range against a wall, yes. It’s also a convenient number, because staying at or below 400 CFM keeps you under the make-up air threshold. With a professional-style range, an island cooktop, or a long duct run, 400 CFM will feel underpowered.
Can a range hood be too powerful for a kitchen?
Yes. Beyond the make-up air requirement, an oversized blower in an undersized duct gets loud, and a hood people won’t turn on because of the noise captures nothing. More airflow is only better up to the point the rest of the system can support it.
How high above the range should a hood be mounted?
Follow the manufacturer’s specification for the exact model, typically somewhere between 24 and 36 inches above the cooking surface. Mounting higher than specified spreads the capture area and loses the plume. The specification sheet governs, not a general rule of thumb.
Do I need a hood over an electric or induction cooktop?
Yes. Electric and induction produce no combustion byproducts, but cooking itself generates grease, steam and fine particles regardless of the heat source. You can usually specify less airflow than a comparable gas range needs, but venting outside is still the right answer.
Is a louder hood a sign of a more powerful one?
No. Noise is usually a duct problem, not a power measurement. A blower forced through undersized or flexible duct is loud because the air is fighting resistance. Hood noise is rated in sones, and a well-ducted high-airflow hood can be quieter than a poorly ducted small one.
Can I add a range hood without a full kitchen remodel?
Sometimes. If the range already sits on an exterior wall with a clear path for a duct, replacing a hood is straightforward. If it sits on an interior wall or an island with no existing duct, the work reaches into ceilings, soffits or cabinetry.
Get the Hood, the Range and the Duct Specified Together
Hood sizing looks like an appliance question and behaves like a construction question. The airflow you need depends on the range you chose, the duct you can actually build, and whether the number crosses a line that adds a mechanical system to the project.
If you’re planning a kitchen and haven’t settled the ventilation yet, request a design consultation and we’ll work through the range, the hood and the duct path together, while all three are still easy to change.