Buzzing, banging, dripping, or vibrating noises from your hood - even when it’s off - driving you crazy?
Just by mentioning these cases, we’re already excluding all the noises that occur while the hood is running for which I’ve written a dedicated guide (which I encourage you to read).

In this article, however, we’ll focus on those unexpected sounds that occur when the hood is turned off. Let’s get straight to it by listing the different types of noises you might hear—along with their causes and possible solutions.

If you feel you need a specialized technician to help diagnose the issue with your hood, feel free to contact me directly.

Common Cases of Noises When the Hood Is Off

Warning: Whatever action you need to take to eliminate the noise, make sure the hood is completely turned off and disconnected from the power supply before performing any maintenance! This is essential to ensure your safety during any intervention.

Woman turning off the hood before checking it

Drafts in the Duct

Do you hear drafts or the sound of wind blowing into the hood duct?
If you have a ducted extractor hood, it’s most likely due to the non-return valve (the classic "butterfly" flap), which may be damaged or loose, allowing air to enter the duct when the hood is off.

To fix this issue, inspect the non-return valve and replace it if the flaps show cracks, deformations, or don’t seal properly.

Constant Electrical Buzz

Do you hear a faint but continuous buzzing noise coming from the hood even when it’s off? It’s most likely the transformer.

This isn’t a serious issue, but if you want to eliminate it:

  • Replace the transformer with a new, quieter model.

  • Isolate the circuit board from the metal casing using rubber spacers, especially if the buzz is caused by vibrations.

Banging Non-Return Valve

If your hood vents air to the outside and you hear an intermittent banging noise, the culprit might be the non-return valve.

The "butterfly" flap inside the valve can become loose or deformed, and even small air currents can make it rattle when the hood is off.

To solve this:

  • Replace the valve.

  • Check that the valve’s housing is perfectly aligned.

Birds or Small Animals in the Duct

In some cases, you might even hear scratching or chirping sounds coming from the hood.
This could be caused by small animals nesting inside the duct.

The solution is to remove the nest, calling in a professional if needed, and install anti-intrusion grilles to prevent it from happening again.

Dripping or “Tick-Tick” From Condensation

If the duct runs through cold areas before reaching the outside, temperature differences can cause humidity to condense, forming droplets that drip and make noise.

To fix it:

  • Insulate the duct to avoid thermal shock.

  • Check the exterior outlet to ensure that water isn’t entering from outside.

Loud Vibration While Off

If you hear a strong vibration coming from the hood while it’s off and the noise only stops when the power is disconnected it may be a problem with the transformer or the electronic board.

Try the following:

  1. Disconnect the power and unplug the hood’s electronic board.

  2. If the noise persists when you power it back on, the issue may lie elsewhere in the system.

None of These Issues Apply? Contact a Technician!

Contact Tiziano for noise when hood is turned off

Have you tried following these tips but still haven’t solved the problem? Or would you prefer the opinion of an experienced technician?

In either case, get in touch with me!
With over 20 years of experience in servicing and diagnosing kitchen hoods, I’ve handled dozens of different situations and can recommend the best solution for your specific case.

Also, remember that at Filtro Cappa, you’ll find all the spare parts - both original and compatible - for your kitchen hood, even if it’s an older or discontinued model!