How Many m³/hr Does My Rangehood Actually Need for Wok Cooking?

Every rangehood listing throws an "m³/hr" number at you, but almost nobody explains what it means or how to tell if it's actually enough for how you cook. If you're used to wok cooking — high heat, fast, with a serious amount of smoke and oil vapour in a short burst — that number matters far more than it does for someone simmering a pasta sauce, and most standard rangehood guidance simply isn't written with that in mind.

Here's what m³/hr actually measures, how it's normally sized, and why wok cooking pushes that number a lot higher than the general advice suggests.

What Does m³/hr Actually Mean?

m³/hr (cubic metres per hour) is the volume of air a rangehood can pull through and extract in one hour, measured at the rangehood's maximum fan speed. It's a straightforward measure of raw pulling power: the higher the number, the more air — and everything suspended in it, including smoke, steam and airborne oil particles — the rangehood can clear in a given amount of time.

It's not a measure of noise, suction "strength" at the cooktop surface, or how the rangehood will perform day-to-day at its lowest, quietest setting. It's simply the ceiling: the most air the unit can move when you need it to.

The General Sizing Rule (and Why It Falls Short for Wok Cooking)

The standard kitchen formula

Most rangehood buying guides size extraction against your kitchen's volume: multiply your kitchen's length × width × height (in metres) to get its volume in m³, then multiply that by the recommended number of air changes per hour for a kitchen — typically somewhere around 15–20 for domestic cooking. That gives you a rough minimum m³/hr figure.

For an average Australian kitchen, this formula usually lands somewhere in the 600–1000 m³/hr range — which is exactly why a lot of standard rangehoods on the market sit in that band. It's a reasonable baseline for general cooking: boiling, baking, pan-frying at moderate heat.

Why wok cooking needs more

The kitchen-volume formula assumes fairly gentle cooking. It doesn't account for the volume of smoke and oil vapour produced in the first 60–90 seconds of a wok hitting high heat, which is dramatically more than the same formula assumes for everyday cooking. Wok cooking doesn't just need a rangehood that can technically clear your kitchen's air over an hour — it needs one that can clear a sudden, concentrated burst of smoke and oil the moment it happens, before it settles on your cabinetry or drifts through the rest of the house.

This is the gap most sizing guides miss, and it's the reason a rangehood that looks "big enough" on paper can still leave your kitchen smelling like last night's stir-fry.

How Much Extraction Does Wok Cooking Actually Need?

As a practical guide:

• Light to moderate cooking (boiling, baking, occasional pan-frying): 600–1000 m³/hr is generally adequate.

• Regular pan-frying and higher-heat Western cooking: 1000–1500 m³/hr is a safer minimum.

• Wok cooking and high-heat Asian-style cooking, done regularly: look for 2000 m³/hr or higher. This is the range where a rangehood can actually keep pace with a hot wok rather than playing catch-up.

Robam's rangehoods are built around that upper end specifically — models rated at 2400+ m³/hr extraction are designed for exactly this scenario, where the volume and speed of smoke and oil produced is far higher than general kitchen-sizing formulas assume.

Matching Extraction Rate to Your Cooktop's Power (MJ)

Extraction rate and burner power should be considered together, not separately. A gas burner's output is measured in MJ (megajoules), and the more powerful the burner, the more smoke and oil vapour it's capable of producing at full heat. If you're running (or planning to install) a high-output burner from our Gas Cooktops range for proper wok heat, pairing it with a rangehood rated well below 2000 m³/hr means your extraction becomes the bottleneck — you'll have the heat for real wok hei, but not the airflow to clear what it produces.

Sizing by Rangehood Width (60cm, 75cm, 90cm)

Width and extraction rate aren't the same thing — a 90cm rangehood isn't automatically more powerful than a 60cm one — but width does affect how much of your cooktop and burner area the rangehood can actually capture air from, which matters as much as the fan's raw output.

As a rule of thumb, your rangehood should be at least as wide as your cooktop — ideally a size up — so it can fully capture the smoke and oil vapour rising off every burner, including the wok burner if it sits at one end.

Don't Forget Duct Type and Installation Height

Extraction rate on the spec sheet is a maximum, and two things can affect how much of it you actually get in your kitchen:

• Ducted vs recirculating. A ducted rangehood vents air outside and delivers closer to its rated extraction in real use. A recirculating rangehood filters and recycles air, which is a genuine solution when ducting outside isn't possible (apartments and strata buildings, for example), but it won't match ducted performance for wok-level smoke and oil. We've covered the full comparison, including when recirculating is your only real option, in Ducted vs Recirculating Rangehoods: Which One Actually Clears Smoke and Oil?

• Mounting height. The higher a rangehood sits above the cooktop, the more its effective capture rate drops, even if the rated m³/hr stays the same. If your installer needs to mount higher than the standard 65–75cm above the cooktop for any reason, sizing up in extraction rate helps compensate.

Robam's High-Extraction Rangehoods for Wok Cooking

If you cook at high heat regularly, the extraction rate is the single most important number on the spec sheet — more important than price, colour, or even width alone. Robam's rangehoods are engineered around the 2400+ m³/hr end of the market specifically because that's what wok-level cooking actually requires, across every install style:

• Rangehoods — the full range

• Integrated Rangehoods

• Undermount Rangehoods

• Canopy Rangehoods

• Side Suction Rangehoods

Quick Answer: What to Look For

If you only take one thing from this: for regular wok or high-heat cooking, look for a ducted rangehood rated at 2000 m³/hr or higher, sized at least as wide as your cooktop, and installed at standard mounting height. Anything below that and you're likely to notice smoke and oil lingering in the kitchen, no matter how good your technique is.