How Often Should You Replace Your CPAP Filter? An RRT's Complete Guide

Most CPAP users replace their filters far too infrequently. As a Registered Respiratory Therapist who reviews hundreds of AirView therapy reports, this is one of the first things I check — and it is almost always overdue.

Disposable filters — replace every 2 weeks

These thin white filters are single-use. Most people treat them like reusable filters and leave them in for months. After 2 weeks they are clogged enough to restrict airflow, which forces your machine to work harder and can increase your AHI.

How to tell it is time: The filter looks grey or discolored, or your machine sounds slightly louder than usual.

Reusable foam filters — wash monthly, replace every 6 months

The thicker grey or blue foam filter is reusable but only up to a point. Wash it monthly with mild soap and warm water, let it dry completely before reinserting. After 6 months the foam breaks down and loses its filtering effectiveness.

How to tell it is time: The foam looks compressed, has small tears, or does not spring back when you squeeze it.

What happens if you do not replace filters:

• Your machine works harder to pull air through a clogged filter
• Reduced airflow can cause your auto-adjusting machine to increase pressure unnecessarily
• Dust, allergens, and bacteria end up in your airway
• Motor strain shortens the life of your machine

Which filters does your machine use:

• ResMed AirSense 10 and 11: Uses both a disposable fine filter (replace every 2 weeks) and a reusable foam filter (wash monthly, replace every 6 months)
• Philips DreamStation 2: Uses a reusable blue foam filter (replace every 6 months)
• Fisher and Paykel SleepStyle: Uses a replaceable filter cartridge (replace every 6 months)

Have questions about your specific machine? Book a BreatheSession and I will review your full setup.

By Ejona J., RRT — Desert Breathe