The Philips AC3421 takes the Philips FY3401/00 Humidification Filter (PureProtect Water 3400 AC3420, AC3421) as its wick filter; replace it every 6 months; Australian sellers list it from A$34.00 as of 28 October 2026. Fitment confirmed against the manufacturer's compatibility list.
Your humidifier
Philips AC3421
Humidifier
Confirmed against Philips's listConfirmed against Philips's own compatibility list
Not yours? ChangeSave it · remind me every 6 months
Takes the FY3401/00 wick filter
FY3401/00 Humidification Filter (PureProtect Water 3400 AC3420, AC3421) · replace every 6 months · check the code printed on your old filter before ordering.
Your humidifier
Humidifier
Confirmed against Philips's listConfirmed against Philips's own compatibility list
Takes the FY3401/00
Wick filter · every 6 months · check the code on your old filter.
Other Philips humidifiers that take the FY3401/00
GenuineGenuine Philips
$34.00
Amazon AU · 28 OctLowest genuine · Amazon AU · checked 28 Oct
CompatibleCompatible option
See seller
No compatible seller tracked yetNo compatible seller tracked yet
Genuine: made by Philips. Compatible: another brand.Genuine is made by Philips. Compatible is made by another brand. Check the seller's page for the size and models it fits.
Lowest price · $34.00
Amazon AU. Every seller we track is listed below. Some links earn us a commission. Some seller links earn us a commission, at no extra cost to you.
This humidifier also takes a filter
- Philips FY3400/30 HEPA NanoProtect Filter (PureProtect Water 3400 AC3420, AC3421)Open Amazon AU$83.85
The purifier side's HEPA filter, changed separately from the wick. Separate from the wick filter. Reduces fine dust and pollen. Replace every 12 months.
Compare 1 seller
AUD, before delivery. Each price shows when it was checked.
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Not due yet?
Get a nudge when your wick filter is due — it's every 6 months. One email two weeks before, no newsletter. Manage or stop it anytime.
How to change the wick filter in your Philips AC3421
Watch the guide or follow the steps.
- 1Switch the purifier off and unplug it.
- 2Pull the water tank out of the purifier.
- 3Take the bracket off the old humidification filter and throw the filter away.
- 4Unwrap the new FY3401 filter and fit the bracket around it.
- 5Put the water tank back in.
Every number this part goes by
- Retail name:
- FY3401
- Retail name:
- FY3401-00
- Retail name:
- FY3401/00
Sellers list any of these; they are the same part.
About your Philips AC3421
Philips humidifier — PureProtect Water 3400 Series. Its wick filter is the FY3401/00 Humidification Filter (PureProtect Water 3400 AC3420, AC3421), part FY3401/00, changed every 6 months.
Also in this humidifier: Philips FY3400/30 HEPA NanoProtect Filter (PureProtect Water 3400 AC3420, AC3421) (every 12 months). The purifier side's HEPA filter, changed separately from the wick.
Where the model number is: The model is on the label under or on the back of the unit, and on the box. Unplug it and empty the tank before you turn it over.
Common questions
- Which wick filter fits the Philips AC3421?
- The Philips AC3421 takes the Philips FY3401/00 Humidification Filter (PureProtect Water 3400 AC3420, AC3421).
- How often should I replace the wick filter in my Philips AC3421?
- Every 6 months. It works less well as the filter fills up, so it's worth doing on time.
- Where can I buy the FY3401/00 in Australia?
- We track 1 Australian seller for the FY3401/00; the lowest listed price when we last checked was A$34.00 at Amazon AU. Prices are re-checked daily and dated on this page.
- How do I fit the FY3401/00 in a Philips AC3421?
- No tools, a few minutes: 5 steps, listed on this page with the replacement video where the maker has one.
- What happens if I don't change it?
- A scaled-up wick soaks up less water, so the room gets less moisture for the same running time.
- How do I reset the reminder?
- No counter to reset for this filter. The filter cleaning reminder is cleared by holding the two buttons the manual shows for 3 seconds, or in the Philips Air+ app.
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