Cleaning Thermador Range Hood Filters (and Why the Hood Went Quiet)

The reason this page exists

More than a few "my hood has stopped working" calls end at a set of filters that have not been washed since the kitchen was installed. Grease saturates the baffles, air stops going through them, and a perfectly healthy blower moves nothing. It is the cheapest fix in the house and the one nobody gets to before booking.

Getting them out

With the hood cool and switched off:

Baffle filters lift slightly and pull out by the handle at the front. There is usually a small catch or lip to clear first — they are heavy, they are sharp-edged, and two hands is the right number.

Note which way round they came out. They have an orientation, and refitted the wrong way they whistle and let grease past.

Washing them

Dishwasher. Stainless baffles go on a hot cycle, on their own. Aluminum mesh filters survive it and come out dull — they still work, so it is a question of how the kitchen looks.

By hand. Hot water, dish soap, a good spoonful of baking soda, and twenty minutes of soaking before you touch them with a brush. The soak does the work; scrubbing a dry filter does not.

Dry them completely before they go back. A damp filter in a warm hood develops a smell of its own within days.

How often

• Cooking most days, with a gas top: monthly
• Cooking a few times a week: every two to three months
• A second kitchen or a rarely used range: twice a year, and check them anyway

Frying and searing shorten every one of those intervals. So does a downdraft, which pulls grease across a longer path than a wall hood does.

The filter that cannot be washed

If your hood recirculates rather than venting outside, it also has a charcoal filter. It handles smells rather than grease, it is not washable, and it is replaced every six to twelve months.

Plenty of owners of recirculating hoods have never replaced one, which is the usual reason a hood extracts fine and the kitchen still smells of last night.

When clean filters do not fix it

Ventilation on this equipment comes three ways, and where the blower lives changes everything:

• In the hood — the simplest, and the easiest to diagnose
• Inline, in the ceiling run — quieter in the kitchen and frequently on its own circuit
• Remote, outside the building — quietest of all, and the reason a hood can be silent while its controls are perfectly healthy

A hood that does nothing at all is worth checking against every breaker in the house before anything else, because a remote blower is often on one nobody associates with the kitchen. The full symptom page works through it.

Duct runs, honestly

A long horizontal run with several bends costs a surprising amount of airflow, and no amount of cleaning gets it back. If your hood has never extracted well — as opposed to having got worse — the installation is a fairer suspect than the appliance, and that is worth knowing before you pay anybody to look at the blower.

The one to book

A hood that runs on some speeds and not others: that is the speed control rather than the motor, and it is the cheaper of the two. What a hood repair starts at — it is the least expensive appliance on this site, and we would rather say so.