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Cooker hood filter calculator

Clean a metal grease filter after 20 to 40 hours of cooking, and every 4 weeks at most. Change a charcoal filter after 120 to 180 hours, and every 6 months at most.

Count the time the fan actually runs, including the minutes after cooking.
How do you cook?
Where does the air go?
A hood with no duct to the outside recirculates: it cleans the air through an odour filter.

Your filters

Grease filter: clean it Every 4 weeks At 1 hour a day the 30 hours take longer than 4 weeks, and Miele says to clean the grease filter every 3 to 4 weeks anyway1.

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How we worked this out

Hoods count hours, not weeks. Miele’s hoods light the grease-filter symbol after 30 hours of use by default, 20 hours if you fry regularly and 40 to 50 hours if you use very little fat1,2; we take 40 for little fat. AEG’s hoods ask after about 40 hours3. Grease left too long hardens in the mesh, so Miele also says to clean the filters every 3 to 4 weeks even if the symbol hasn’t come on; we use 4 weeks1.

A recirculating hood blows the air back into the kitchen through an odour filter. Miele’s charcoal counter runs 180 hours by default and 120 hours if you often cook strong-smelling food1; we count “lots of frying” as that. AEG says about 160 hours3. Either way Miele says to change it after 6 months1. Charcoal can’t be washed, only replaced6.

A regenerable (Long Life) odour filter goes in the oven instead. BSH, which makes Bosch, Siemens and Neff, says that at about 1 hour a day it needs regenerating every 3 to 4 months, up to 30 times, and replacing after 10 years at most4; Siemens says every 4 months5. We read that as 90 hours of use, and every 4 months at most.

The interval is whichever comes first: the hours divided by how long your hood runs a day, rounded down to whole days, or the calendar limit. A metal grease filter goes in the dishwasher on its own at up to 65 °C5,2. If your hood has its own filter light, that knows your hood best.

Sources

  1. 1
    Operating and installation instructions, DAC 4240 / DAC 4940 ceiling cooker hood (M.-Nr. 12 614 740) Miele · Maker · checked Oct 18, 2026
  2. 2
    Operating and installation instructions, DA 3690 ventilation hood (M.-Nr. 10 625 750) Miele USA · Maker · checked Oct 18, 2026
  3. 3
    How to clean the filters on your AEG cooker hood AEG UK · Maker · checked Oct 18, 2026
  4. 4
    Long Life recirculation set, installation and use (9001831647) BSH Hausgeräte · Maker · checked Oct 18, 2026
  5. 5
    Filter für Dunstabzugshauben: Pflege und Wartung Siemens Hausgeräte Schweiz · Maker · checked Oct 18, 2026
  6. 6
    Reinigung des Filters Ihrer Dunstabzugshaube Bosch Hausgeräte Schweiz · Maker · checked Oct 18, 2026

These are the makers’ figures for typical use. If your appliance’s manual or its own indicator says otherwise, go with that.