A ducted stove hood is the gold standard of kitchen ventilation. Instead of filtering cooking air and blowing it back into the room, a ducted (vented) hood captures the smoke, grease, moisture, odors, and combustion gases that rise off your cooktop and pushes them outside your home through ductwork. That single difference—removing pollutants entirely rather than recirculating them—is why a properly installed vented hood protects your indoor air, your cabinets, and your walls better than any other option. If you have, or can create, a path to an exterior wall or roof, a ducted hood is worth it. This complete guide covers how it works, how to size the airflow and ductwork correctly, what make-up air is, how to install and maintain one, and which ROBAM models to consider—so browse the full range hood collection as you read.
What is a ducted stove hood?
A ducted stove hood—also called a vented range hood, exhaust hood, cooker hood, or extractor—is a hood that connects to ductwork and expels cooking air outdoors. “Ducted” simply means “vented to the outside.” It sits above your stove, draws in the rising plume, traps grease in metal filters, and then sends the remaining smoke, steam, and gases through a duct that terminates at an exterior wall cap or roof cap.
The alternative is a ductless (recirculating) hood, which filters air through a charcoal cartridge and returns it to the room. Ductless is the right choice when you genuinely can’t run a duct—typically apartments and rentals—but for grease, moisture, and especially combustion gases, it can’t match a hood that removes that air from the building. In short: if you can duct, duct.
How a ducted stove hood works
Every ducted hood performs the same job in a sequence of stages. Understanding them helps you see why sizing and installation matter as much as the hood itself.
- Capture. A canopy or collection screen positioned over the cooktop catches the thermal plume as it rises. A larger, lower capture area intercepts more of the smoke before it drifts into the room.
- Grease filtration. Air passes through metal baffle or mesh filters that condense and trap grease droplets. These are washable—most are dishwasher-safe—so grease doesn’t coat the motor or the duct.
- The blower/motor. A fan (ideally a brushless BLDC motor) generates the airflow and the static pressure needed to move air through the duct run.
- The duct. Rigid metal ductwork carries the air toward the exterior, sized to the hood’s airflow so it doesn’t choke.
- Exterior termination. The duct ends at a wall cap or roof cap fitted with a backdraft damper (which opens to let air out and closes to keep weather, pests, and cold air out).
The key insight is that a hood is only as good as the weakest link in this chain. A powerful motor with an undersized, bend-heavy duct will underperform a modest hood on clean, short, straight ducting.
Why ducted is the gold standard
Kitchens are the primary source of indoor air pollution in most homes. High-heat, oil-based cooking releases fine particles (PM2.5) and ultrafine particles; gas and propane burners add nitrogen dioxide (NO₂) and carbon monoxide (CO); and every meal produces grease aerosols, odors, and moisture. A ducted hood is the only setup that physically removes all of that from your living space. The benefits stack up:
- Removes combustion gases. Only outdoor venting fully clears NO₂ and CO from a gas stove—a recirculating charcoal filter barely touches them.
- Removes moisture and heat. Boiling, steaming, and frying add humidity that a ductless hood simply returns to the room; venting it outside helps prevent condensation and mold, and keeps the kitchen cooler.
- Better grease and odor control. Grease and smells leave the building instead of being partially re-released.
- Protects your home. Less airborne grease means cleaner cabinets, walls, and ceilings, and less sticky residue over time.
- Lower running cost. There’s no charcoal filter to replace every few months—just washable grease filters.
Ducted vs. ductless: which is right for you?
The honest comparison: ducted wins on performance; ductless wins on flexibility of installation. Here’s how they stack up.
| Ducted (vented outside) | Ductless (recirculating) | |
|---|---|---|
| Removes | Grease, smoke, NO₂/CO, heat, moisture — fully | Grease and odors well; gases only partially |
| Best for | Homes with an exterior wall or existing duct | Apartments, rentals, interior kitchens |
| Installation | Needs ductwork to the outside | Almost anywhere; no construction |
| Ongoing cost | Wash grease filters; no charcoal | Replace charcoal filters periodically |
| Best for gas cooking | Yes — clears combustion gases | Limited — gases stay in the room |
If ducting isn’t possible today, a convertible hood lets you recirculate now and duct later. For a deeper look at the recirculating option, see our guide to kitchen ductless range hoods.
Types of ducted stove hoods
“Ducted” describes the venting method; it’s available across nearly every hood style. Choose the style based on where your cooktop sits.
- Under-cabinet: mounts beneath a wall cabinet above the stove—the most common style, vented horizontally through the wall or vertically through the cabinet. See the under-cabinet range hood collection.
- Wall-mount (chimney): mounts on the wall with no cabinet above, using a large canopy for strong capture and a visible duct cover. Explore the wall-mount range hood collection.
- Island: suspended from the ceiling over an island cooktop, always vented vertically up through the roof.
- Built-in / insert: the motor-and-filter unit hidden inside custom cabinetry, ducted out of sight.
- Downdraft: rises from behind the cooktop and ducts down and out—useful where an overhead hood isn’t possible.
Sizing step 1: how much CFM do you need?
CFM (cubic feet per minute) measures how much air the hood moves. Match it to your cooktop and cooking style—too little and smoke escapes, too much and you may need make-up air (more on that below).
- Electric cooktops: a simple rule is 10 CFM per inch of cooktop width—so a 30-inch cooktop wants roughly 300 CFM as a baseline, more for heavy cooking.
- Gas cooktops: size by heat output—about 100 CFM for every 10,000 BTUs, which is the same as dividing your total BTUs by 100. A 60,000 BTU range points to ~600 CFM.
- Island hoods: add about 50% more CFM, because there’s no back wall to funnel smoke and the hood is exposed to cross-drafts.
- Heavy wok or high-heat cooking: step up to 900–1,500 CFM with strong static pressure.
Remember that capture efficiency—how well the hood covers your burners—matters as much as the raw CFM number. A large, well-positioned capture screen close to the cooktop clears smoke better than a higher-CFM hood with a small intake.
Sizing step 2: ductwork — the make-or-break
This is where most ducted hoods succeed or fail. A high-CFM motor throttled by the wrong duct will be loud and weak. Get these right:
Duct diameter (match it to your CFM)
| Hood airflow | Minimum duct | Recommended duct |
|---|---|---|
| Up to 400 CFM | 4″ | 6″ |
| 400–600 CFM | 6″ | 6–8″ |
| 600–900 CFM | 7″ | 8″ |
| 900–1,200+ CFM | 8″ | 8–10″ |
Never reduce the duct below the hood’s outlet size—an undersized duct chokes airflow, forces the motor to work harder, and adds noise. When in doubt, follow the manufacturer’s specification sheet, which takes precedence over general rules.
Duct material: rigid metal only
Use rigid, smooth-walled metal duct (galvanized steel or stainless). Its smooth interior minimizes resistance and doesn’t trap grease. Avoid flexible “slinky” and semi-rigid duct: the corrugated ridges create turbulence that kills airflow and collect flammable grease that’s nearly impossible to clean. Never use PVC, vinyl, or plastic—they’re flammable and not rated for kitchen exhaust heat.
Keep it short and straight
The shorter and straighter the run, the better the hood performs. Keep the total run under about 30 feet, and use as few elbows as possible—no more than three. Each 90-degree elbow adds significant resistance, roughly the equivalent of 5 to 15 feet of straight pipe; where you must turn, two 45-degree elbows create less turbulence than one 90, and multiple bends should be spaced a few feet apart. Round duct also outperforms rectangular duct of the same cross-section because it offers less surface for air to drag against. Slope horizontal runs slightly toward the exterior so condensation drains outside, and seal every joint with metal (UL-181) tape or mastic.
Where does a ducted hood vent — wall or roof?
A ducted stove hood must terminate outside—never into an attic, soffit, or wall cavity, where grease and moisture accumulate and create fire and mold hazards. You have two routes:
- Through an exterior wall (horizontal): usually the easiest and most efficient when the cooktop is on an outside wall. It offers a short run, good airflow, and easier sealing, and avoids roof penetrations that can leak.
- Through the roof (vertical): necessary for island cooktops and central kitchens. For roof caps, follow the 3-2-10 rule—the vent should rise at least 3 feet above the roof and be 2 feet higher than anything within a 10-foot radius—to draft properly and prevent moisture re-entry.
Either way, fit a wall or roof cap with a backdraft damper and pest screen so air flows out but weather and animals stay out.
Make-up air: the 400 CFM rule
A powerful ducted hood removes a lot of air—and in a tightly built modern home, that air has to be replaced. When it can’t leak back in fast enough, the hood creates negative pressure (a partial vacuum) that can pull humid outside air through walls, or—more dangerously—pull combustion gases like carbon monoxide back down the flue of another gas appliance (backdrafting).
That’s why building codes address it. Under the 2018 IRC (Section M1503.6), if a range hood is capable of exhausting more than 400 CFM, a make-up air (MUA) system must be provided—particularly in homes with atmospherically vented gas appliances. A make-up air system uses a motorized damper that opens automatically when the hood runs, providing a clean path for replacement air. In very tight homes with combustion appliances, it’s worth considering make-up air even below 400 CFM.
Quick reference: do you need make-up air?
Over 400 CFM, or a tight home with atmospherically vented gas appliances → yes, plan for make-up air. Always check your local building code, since requirements vary by jurisdiction, and consult a professional for combustion-safety-sensitive installations.
Installation essentials
Ductwork, electrical, and roof or wall penetrations are best handled by a licensed professional, but here are the fundamentals every ducted install should follow:
- Mounting height: 24 to 30 inches above the cooktop for most hoods (some allow up to 36 inches). Too high and you lose capture; too low risks heat damage.
- Electrical: most residential hoods run on 120V drawing a few amps, but higher-CFM models (roughly 900+ CFM) may need a dedicated 15–20 amp circuit.
- Retrofit vs. new build: a wall exit on an exterior wall is the simplest retrofit; island and roof runs are more involved. Replacing an over-the-range microwave or old hood with a ducted model is a common slot-for-slot upgrade.
- Insulate cold runs: duct passing through unconditioned or cold space should be insulated to prevent condensation, which also reduces blower noise.
For a step-by-step walkthrough of duct, vent, and electrical requirements, see ROBAM’s range hood installation guide.
Noise, motors, and running your hood
A common myth is that ducted hoods are loud. Noise actually comes from the motor type, turbulence, and poor ducting—not from venting outside itself. Modern brushless BLDC motors run far quieter and more efficiently than older AC motors, and they offer precise variable speed so you can run a gentle, near-silent setting for everyday cooking and only boost when searing. Clean, rigid, correctly sized duct keeps turbulence low, and insulated duct further dampens blower noise. To go deeper, read why a BLDC brushless motor lasts longer and how to read range hood noise ratings. Whatever hood you choose, the golden rule is simple: run it every time you cook, and start it a minute before and leave it on 10–15 minutes after.
Maintenance
Ducted hoods are refreshingly low-maintenance. Wash the metal baffle or mesh grease filters regularly—most are dishwasher-safe—so airflow stays strong and grease doesn’t reach the duct. Wipe the interior and check that the backdraft damper opens and closes freely. Because there’s no charcoal filter to replace, you avoid the recurring cost and hassle of a ductless system. Every year or two, inspect the duct run and exterior cap for grease buildup, especially if you fry often.
ROBAM’s best ducted stove hoods
ROBAM engineers its ducted hoods around high-efficiency BLDC motors, strong static pressure, and large capture screens. A few standouts:
ROBAM 88H3S — best for high-BTU & heavy cooking
36″ wall-mount · up to 1,500 CFM · 1,000 Pa · ~49 dB · Dual-Vent capture
The 88H3S is built for powerful gas ranges and wok cooking, with an eight-sided Dual-Vent design that boosts capture and enough static pressure to push air through real ductwork—yet it stays around 49 dB thanks to its BLDC motor.
ROBAM A832 — best slim 36-inch ducted
36″ under-cabinet · up to 1,100 CFM · ~42 dB · three-stage filtration
The A832 delivers strong ducted extraction from an ultra-slim body, with a three-stage filtration system that targets fumes, odors, and VOCs—useful for gas and propane cooking.
ROBAM A672 — best for front-burner capture
30″ under-cabinet · up to 1,050 CFM · slant side-draft
The A672 uses a slant, side-draft screen tuned to grab front-burner smoke—the area most hoods miss—making it a strong ducted choice for cooks who sear and fry.
Prefer flexibility? Convertible models like the 86H1S and U3 run ducted now and ductless later, and the quiet 36-inch A679S pairs a 120,000-RPM BLDC motor with noise as low as 34 dB(A).
Common ducting mistakes to avoid
- Undersized duct: the number-one performance killer—always match or exceed the hood’s outlet size.
- Flexible or plastic duct: traps grease, adds turbulence, and can be a fire hazard—use rigid smooth metal.
- Too many bends: keep it under three elbows and prefer two 45s to a single 90.
- Venting into the attic or soffit: never—always terminate fully outdoors.
- Skipping make-up air: over 400 CFM (or in tight homes with gas), you risk backdrafting and moisture problems.
- Wrong mounting height: above 30–36 inches capture drops sharply.
- Not running it—or running it too low: the best hood does nothing switched off.
The bottom line
A ducted stove hood is the most effective way to keep your kitchen air clean, because it removes grease, smoke, moisture, and combustion gases from your home entirely. To get its full benefit, size the CFM to your cooktop, use short, straight, correctly sized rigid metal duct, vent fully outdoors, add make-up air if you exceed 400 CFM, and mount it at the right height. Do that, and a quality hood will keep your kitchen cleaner and healthier for years. Start by exploring the ROBAM range hood collection.
Frequently asked questions
What is a ducted stove hood?
A ducted (vented) stove hood connects to ductwork and expels cooking smoke, grease, gases, heat, and moisture outdoors, rather than filtering the air and returning it to the room like a ductless hood. It’s the most effective form of kitchen ventilation.
Is a ducted range hood better than ductless?
For performance, yes—ducted removes grease, combustion gases, heat, and humidity from your home entirely. Ductless is the practical choice only when you can’t vent outdoors, such as in an apartment. If you can duct, duct.
Do I need a ducted hood for a gas stove?
It’s strongly recommended. Gas burners release nitrogen dioxide and carbon monoxide that only outdoor venting fully removes; a recirculating charcoal filter leaves those gases in the room. Size a gas hood at about 100 CFM per 10,000 BTUs.
What size duct do I need for my range hood?
Match it to CFM: 6″ for up to ~600 CFM, 8″ for 600–900 CFM, and 8–10″ for 900–1,200+ CFM. Never reduce below the hood’s outlet size, and use rigid smooth metal duct rather than flexible.
Where should a ducted hood vent—wall or roof?
Through an exterior wall is easiest and most efficient when the stove is on an outside wall; through the roof is needed for islands and central kitchens. Always terminate fully outdoors with a capped, damper-fitted vent—never into an attic or soffit.
Do ducted range hoods need make-up air?
If the hood can exhaust more than 400 CFM, most codes require make-up air, especially in homes with atmospherically vented gas appliances. It prevents negative pressure that can cause backdrafting and moisture problems. Check your local code.
How long can a range hood duct run be?
Keep it under about 30 feet total for a straight run, with fewer for each added elbow, and no more than three elbows. Shorter and straighter is always better—long, bendy runs raise static pressure, cut airflow, and increase noise.
Can I convert a ductless hood to ducted later?
If your hood is a convertible model, yes—it’s designed to run either way, so you can add ductwork when you gain an exterior path. If you know you’ll want to duct eventually, choose a convertible hood from the start.
Duct sizing, make-up air, and installation guidance reflect widely used kitchen-ventilation best practices and the 2018 IRC (Section M1503.6); requirements vary by jurisdiction, so confirm local building codes and use a licensed professional for ducting, electrical, and combustion-safety-sensitive work. ROBAM product figures reflect published specifications and vary by model—confirm details and current pricing on each product page.
