FitMatch

The Löwenstein prisma 20C takes the Löwenstein prisma air filter / coarse dust filter (set of 2) (part WM 29928) as its filter; replace it every 6 months; Australian sellers list it from A$4.50 each as of 2 November 2026. Fitment confirmed against the manufacturer's compatibility list.

Löwenstein prisma 20C

Your CPAP machine

CPAP machine

Confirmed against Löwenstein's list

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WM 29928

Takes the WM 29928

Filter · every 6 months · check the code on your old filter.

Other Löwenstein CPAP machines that take the WM 29928

Genuine

$4.50 each

2-pack $9.00

CPAP Club · 2 Nov

Compatible

See seller

No compatible seller tracked yet

Genuine: made by Löwenstein. Compatible: another brand.

Lowest price · $4.50 each · 2-pack $9.00

CPAP Club. Every seller we track is listed below. Some links earn us a commission.

Open CPAP Club

This CPAP machine also takes a tubing

Compare 1 seller

AUD, before delivery. Each price shows when it was checked.

CPAP ClubGenuine · checked 2 Nov$4.50 each2-pack $9.00Open
Open cheapest seller · $4.50 each · 2-pack $9.00

Opens CPAP Club in a new tab. Their page is the source of truth for price, delivery and returns.

Not due yet?

Get a nudge when your filter is due — it's every 6 months. One email two weeks before, no newsletter. Manage or stop it anytime.

Also saves the model to a FitMatch account under this address; the email signs you in, no password.

How to change the filter in your Löwenstein prisma 20C

Watch the guide or follow the steps.

prisma SMART max set up video · Löwenstein Medical International (official)
  1. 1Turn the machine off and unplug it.
  2. 2Remove the grey air filter (and the white pollen filter, if fitted) from the holder.
  3. 3Put the new grey air filter, and the white pollen filter if you use one, back into the holder.
  4. 4Make sure the filters sit properly in the holder before you start the machine.
Every number this part goes by
Retail name:
WM 29928
Retail name:
WM29928

Sellers list any of these; they are the same part.

About your prisma 20C

Löwenstein CPAP machine — prismaLINE. Its filter is the prisma air filter / coarse dust filter (set of 2), part WM 29928, changed every 6 months.

Other filters the maker lists for this CPAP machine: Löwenstein prisma pollen filter / fine filter (set of 12) (every month). Optional white pollen filter: sits with the grey air filter in the holder; replace monthly, Löwenstein says.

Also in this CPAP machine: Löwenstein prisma breathing tube, 19 mm (non-heated) (every 12 months).

Where the model number is: The model is on the label under the machine and in its settings or information screen. Unplug the machine, and take out the water tub if it has one, before you turn it over.

Fits these 4 Löwenstein models
Common questions
Which filter fits the Löwenstein prisma 20C?
The Löwenstein prisma 20C takes the Löwenstein prisma air filter / coarse dust filter (set of 2) (part WM 29928).
How often should I replace the filter in my Löwenstein prisma 20C?
Every 6 months. It works less well as the filter fills up, so it's worth doing on time.
Where can I buy the WM 29928 in Australia?
We track 1 Australian seller for the WM 29928; the lowest listed price when we last checked was A$4.50 at CPAP Club. Prices are re-checked daily and dated on this page.
How do I fit the WM 29928 in a Löwenstein prisma 20C?
No tools, a few minutes: 4 steps, listed on this page with the replacement video where the maker has one.
What happens if I don't change it?
A blocked filter restricts the air the machine draws in, and a torn one lets dust and pollen through; the manual says when to replace it.
Is there anything to reset afterwards?
No reset step in Löwenstein's prisma manuals.

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