How Often Should You Change Your CPAP Filter? (AirSense 10, AirSense 11 & S9)
Updated 2026-10-30 · RestWell CPAP
A plain guide to checking and replacing the disposable air filter in ResMed AirSense 10, AirSense 11 and S9 machines, and the signs a filter needs changing early.
Why the filter matters
Your CPAP machine pulls in room air all night and pushes it into your airway. The air filter is the only thing between the dust, pet hair and pollen in your bedroom and your lungs. A clogged filter also makes the blower work harder, which can add noise and wear to the machine.
The short answer
Check the filter at least once a week, and replace a disposable filter at least once a month. Your machine's user guide gives the manufacturer's exact schedule, so follow it if it says something different. Many CPAP users replace filters every two weeks, especially in dusty homes or homes with pets.
- Check weekly: pop the filter cover and look at the color.
- Replace monthly at a minimum, or sooner if it looks dirty.
- Replace right away if it's torn, damp or blocked.
Signs your filter needs changing now
- It has turned gray or brown instead of white.
- You can see dust, lint or hair on the surface.
- It got wet. Never dry and reuse a damp disposable filter.
- It's torn, bent or no longer sits flat in the slot.
- The machine sounds louder than usual.
Disposable filters can't be washed
The white disposable filters used in the AirSense 10, AirSense 11 and S9 are made of a fine fibre that traps particles. Washing them damages the fibre and leaves moisture inside the machine. Throw a used filter away and put in a fresh one.
Which filter fits your machine
The AirSense 10 and the older S9 use the same filter shape (part number CF2107-1 style). The AirSense 11 uses a different, smaller filter (CF2111-1 style). The two are not interchangeable. If you're not sure which machine you have, the model name is printed on the front and on the label underneath.
How to replace it
- Turn the machine off and unplug it.
- Open the filter cover. Your user guide shows where it is on your model.
- Remove the old filter and throw it away.
- Put in a new filter, then close the cover until it clicks.
- Never run the machine without a filter in place.
Does insurance cover filters?
Many insurance plans, including Medicare, cover replacement disposable CPAP filters on a regular schedule, often two a month. Ask your equipment supplier what your plan allows. If you pay out of pocket, buying a multi-pack is usually cheaper per filter.
This guide is general information, not medical advice. Follow your machine's user guide and your healthcare provider's instructions.
