A La Cornue hood — whether the Château Hood built to match a range in color and trim, or the CornuFé 90 and 110 Hoods with their published 600 CFM rating across a 4-speed motor — is mechanically simple: a motor, a fan wheel, deflector-style grease filters, ducting, and a lighting circuit. Weak extraction is one of the most common complaints about any of them, and in the great majority of cases the cause sits at the filters or the duct rather than the motor itself.
Why Filters Matter More Than People Expect
Grease collects on the deflector filters every time the hood runs, and a loaded filter does not just let less air through — it makes the motor work harder to move the same amount of air, which accelerates wear on the motor over time. Cleaning or replacing the filters regularly is not just about airflow today; it protects the motor from a workload it was not designed to run at continuously.
The Duct Is the Other Half
A partly restricted duct run has the same effect as a loaded filter, and the two are easy to confuse without checking each separately. Airflow measured at the hood itself and again at the outside outlet tells you whether the restriction is inside the hood (filters, or grease built up on the fan wheel) or somewhere along the duct run.
Using the Published Rating
The CornuFé 90 and 110 Hoods both carry a published rating — 600 CFM fanless airflow, a 4-speed variable motor, 120V at 540W and 4.5A — which gives a concrete figure to test extraction against rather than relying on an impression of “it feels weaker.” A hood that is measurably below that figure with clean filters and a clear duct points more specifically at the motor or fan wheel than a vague sense that the kitchen clears more slowly than it used to.
The Fan Wheel Connection
Grease does not only collect on the filters; it also builds up on the fan wheel itself, and an unevenly coated wheel both moves less air and starts to vibrate, which is why a rattle at higher fan speeds and a drop in extraction so often show up together and share the same cause. Left running out of balance, a wheel in that state wears its bearings faster than a clean one would.
Running the Hood Longer Than It Looks Like You Need To
Because grease and moisture keep rising from a pan for several minutes after a burner is turned off, La Cornue hoods are built to keep working past the end of cooking, not just during it. Turning the hood on before you start cooking and letting it run for a few minutes afterward clears more of that airborne grease before it can settle back into the filters, which slows how quickly they load up in the first place. Some hoods also offer a delayed-shutoff setting that keeps the motor running automatically for about fifteen minutes after it is switched off by hand, which does the same job without anyone needing to remember to turn it off later.
If your hood is pulling less air than it used to, a La Cornue range hood repair visit checks filters and duct airflow first, and measures against the hood’s rated performance where one is published, before concluding the motor itself has failed.