Commercial Kitchen Exhaust Hood and Ventilation Guide 2026: Hood Types, Airflow Sizing, Makeup Air, Ductwork, Filters and FOB Prices

Walk into a commercial kitchen that “never feels right” — staff sweating, smoke drifting into the dining room, doors that slam by themselves — and the cause is almost never the cooking equipment. It is the ventilation system, and it is the part of a kitchen project that is hardest to fix after handover, because it lives above the ceiling and through the roof. This guide explains how to choose hood types, size exhaust airflow, plan makeup air and ductwork, compare grease-control options, and what a complete ventilation package costs FOB from a China factory.

One boundary note before we start: this article covers air movement — capture, exhaust, makeup air, filtration. The fire side of the same canopy (wet chemical systems, nozzle coverage, fuel shut-off) is a separate discipline with its own standards, covered in our commercial kitchen fire suppression guide.

What type of exhaust hood does your kitchen actually need?

There are four configurations that cover almost every commercial kitchen, and choosing between them is mostly decided by where the cooking line sits in the room.

Wall-mounted canopy hoods are the default for cooking batteries pushed against a wall. Typical depth is 1,100–1,400 mm over a 700- or 900-series line, with the lower edge mounted 1,950–2,100 mm above finished floor. The canopy should overhang the front of the equipment by 250–300 mm (150 mm is a common code minimum) so that thermal plumes that roll forward as pans are worked still land inside the capture zone.

Island canopy hoods hang over free-standing suites open on all sides. Because cross-drafts attack the plume from every direction, they need overhang on all four sides and roughly 20–40% more airflow than a wall canopy over the same equipment; a double-island hood over a back-to-back suite usually beats two single islands.

Low-proximity (back-shelf) hoods sit directly behind and just above counter-line equipment such as griddles, fryers and salamanders. With the capture zone close to the cooking surface they capture at lower airflow than a full canopy — useful in show kitchens where a deep canopy blocks sightlines — but they cannot serve tall equipment like stockpot stoves or combi ovens.

Condensate hoods (Type 2) handle heat and steam only — over dishwashers, combi ovens in banks, steamers and boiling pans in low-grease zones. They have condensate gutters and drain points instead of grease filters. The distinction matters commercially: a grease-duty (Type 1) hood needs baffle filtration and grease-rated ductwork throughout, while a Type 2 hood does not — so putting a dish machine under a Type 1 canopy wastes money, and putting a fryer under a Type 2 hood is a hazard no inspector will pass.

Specialist appliances need their own planning: solid-fuel equipment must never share a duct with other lines, and a smokehouse needs a dedicated route out of the building, as detailed in our commercial smokehouse oven guide.

How much exhaust airflow do you need?

Every mechanical engineer has a preferred method, but the numbers cluster into predictable bands per linear metre of hood, driven by the duty rating of the equipment underneath:

Two sanity checks catch most sizing mistakes. First, face velocity: total exhaust volume divided by the open face area of the hood should land around 0.25–0.5 m/s — below that, smoke spills; far above it, you are paying to condition air you immediately throw away. Second, watch mixed lines: a hood is sized by its hottest section, so one charbroiler parked in the middle of a light-duty line drags the whole canopy up a duty class. It is often cheaper to group heavy-duty appliances under their own hood section.

Site conditions move these numbers. Above roughly 600–700 m altitude, thinner air means fans move less mass per rotation and gas appliances behave differently — the same interaction with burner performance we covered in the commercial kitchen gas supply guide. And a wok line in continuous service behaves nothing like the same line used two hours a day; tell your supplier honestly what the menu does at peak.

Do you need makeup air, and what happens if you skip it?

Yes — this is the most commonly deleted line item in value engineering, and the most regretted. Air removed by the exhaust fan must be replaced; if you do not supply it mechanically, the kitchen pulls it through every gap in the building. Door seals whistle, doors slam or refuse to open, pilot flames wander, the dining room’s conditioned air rushes into the kitchen, and in the worst cases negative pressure interferes with appliance flues.

The working rule is to supply 80–90% of the exhaust volume as makeup air, keeping the kitchen at a slight negative pressure — around 5–15 Pa below adjacent areas — so odours stay in the kitchen without starving the exhaust. Deliver it away from the hood face (perimeter diffusers or low-velocity displacement grilles), because dumping cold air straight at a canopy edge destroys capture.

In hot-climate markets the tempering question dominates the budget. In a Gulf or West African summer, 8,000 m³/h of untempered 45 °C makeup air turns a kitchen into a convection oven; some cooling of the incoming stream — evaporative in dry climates, DX coil where humidity is high — is not a luxury, it is what makes the kitchen staffed. Budget for it from day one rather than discovering it at commissioning, a pattern we see often enough that it features in our installation and commissioning guide.

What should grease ductwork and fans look like?

Grease duct is not ordinary HVAC duct. It should be liquid-tight — continuously welded carbon or stainless steel, not snap-lock — sloped back toward the hood or to drain points, with access panels at changes of direction for cleaning. Design velocity is commonly held at 6–9 m/s: fast enough to keep grease aerosol entrained rather than settling in the run, while respecting whatever minimum your local code sets. Keep routes short and vertical where possible; every extra elbow is pressure the fan must overcome for the life of the building, and every horizontal metre is a future cleaning job.

Fans for grease duty are centrifugal units with the motor out of the airstream — roof-mounted upblast fans, or grease-rated inline cabinet fans where the roof is not available. Match the fan curve to the real calculated system resistance rather than a catalogue guess: oversized is noise and wasted power, undersized is a hood that never captures. Demand-control kitchen ventilation (sensors driving VFDs on exhaust and makeup fans together) routinely saves 30–50% of fan energy, a payback measured in months in high-utility markets.

Which filters and grease-control options are worth paying for?

Stainless baffle filters are the baseline: they force the airstream through sharp direction changes, flinging grease onto the blades and into a collection gutter. Standard modules (about 500 × 500 mm and 500 × 400 mm) drop into the canopy rail and go through the dish machine at closing. Do not accept mesh filters for grease duty — they load up, choke airflow, and become a fire fuse.

UV hood sections mount UV-C lamps behind the baffles to break down grease molecules before they enter the duct, cutting duct cleaning frequency dramatically — worth evaluating on long or inaccessible duct runs. They need airflow interlocks and lamp maintenance discipline.

Electrostatic precipitators (ESP) charge and collect fine grease particles at 90%+ efficiency, and are the standard answer where you cannot discharge at roof level — street-level discharge in a mall, a ground-floor unit under apartments. Pair with activated-carbon modules where odour is the complaint that matters. ESPs are washable, but only if someone actually washes them; put the cells on the same cleaning rota as the filters.

What does commercial kitchen ventilation cost FOB from China?

Indicative FOB price bands for export-grade 304 stainless construction:

Freight is favourable: hoods ship as flat-packed or nested sections and assemble on site with jointing strips, so a full hotel ventilation package rarely dominates container space. Because canopies are fabricated items rather than catalogue boxes, dimensions are free variables — at Grace Kitchen Equipment we cut each hood to the approved drawing: exact lengths to your wall, duct collars positioned to match your planned riser route rather than the centre-of-hood default, service voids for the fire line, and non-standard depths without tooling charges. That single detail — collars where the building needs them — saves more site labour than any other decision in the package.

Ask for the spare-parts position in the same quotation: spare baffle filters (they get dented and lost), fan belts and bearings for belt-driven units, LED fittings and a spare gas-interlock solenoid. We ship a two-year warranty on fabricated canopies and fans with a named spares list in the packing documents, because a ventilation system down for one missing belt stops the whole kitchen, not one appliance.

How do you specify a ventilation package for a China order?

Send your supplier five things: the kitchen layout with each appliance’s duty level marked; ceiling height and any beams crossing the hood zone; the intended duct route to outside; site altitude and summer design temperature; and site voltage/frequency for fan motors. A competent factory returns a hood schedule with airflows per section, fan selections against calculated resistance, and fabrication drawings for approval before anything is cut. If you are still comparing suppliers at that stage, our guide to the top commercial kitchen equipment manufacturers in China covers who can genuinely engineer ventilation rather than just fold stainless boxes.

One caveat that belongs in writing: extraction rates, discharge positions and duct construction are regulated locally, and the local mechanical code or fire authority always outranks any rule of thumb in this article. Have the hood schedule reviewed by the project’s mechanical engineer before release for fabrication — hood clearances also interact with the aisle and spacing rules in our commercial kitchen size guide.

Frequently asked questions

What is the correct height between the hood and the cooking equipment?

The canopy lower edge typically sits 1,950–2,100 mm above finished floor, which puts it roughly 1,000–1,200 mm above the cooking surface of a standard 850–900 mm high line. Go higher and the plume has room to drift sideways before capture; go lower and tall staff work under a steel edge. Overhang matters as much as height — 250–300 mm past the equipment front on every open side.

Can one hood serve both cooking equipment and a dishwasher?

No. Grease-producing equipment needs a Type 1 hood with baffle filtration and grease-rated duct; a dishwasher needs a Type 2 condensate hood with gutters and a drain. Combining them puts steam through grease filters and grease through a steam duct — both wrong. Keep the two systems separate, each with its own fan.

How often should filters and ducts be cleaned?

Baffle filters: daily through the dish machine in a busy kitchen, weekly at minimum in light service. Ductwork: professionally, at intervals set by usage — quarterly for heavy wok or solid-fuel cooking, annually for light duty. UV and ESP systems reduce the burden but do not remove it; keep the cleaning records, because insurers ask for them after any incident.

Do hoods ship assembled or knocked down?

Long canopies ship as flat-packed or nested sections — typically 2–3 m modules — with jointing strips and sealant for site assembly, which keeps freight volume low and lets the sections pass through normal doorways. Fans, filters and interlock panels pack inside the hood sections. A whole ventilation package for a mid-size hotel kitchen usually adds only a few CBM to the equipment container.

Planning a kitchen where the ventilation has to work the first time? Send us your layout and duct route — contact our project team at [email protected] / WhatsApp +86 158 1364 3427, and we will return a hood schedule with airflows, fan selections and fabrication drawings for your engineer’s review.