Noisy Air Leak
CPAP CPAP Machine
Severity: ModerateWhat Does This Error Mean?
CPAP air leak noise is almost always a mask fit issue — the seal is not tight enough against the face. Mask leaks reduce therapy effectiveness and disturb sleep. Adjust the headgear straps, replace worn mask cushions, and try adjusting mask position on the face.
Affected Models
- ResMed AirFit F20
- ResMed AirFit P10
- Philips DreamWear Mask
- Fisher & Paykel Simplus
- ResMed AirTouch F20
Common Causes
- Mask not fitting the face correctly — too large, too small, or worn cushion
- Headgear straps too loose or asymmetric
- Mask cushion worn or degraded — cushions lose their seal after 1-3 months
- Sleeping position — sleeping on the side compresses the mask and breaks the seal
- Facial hair on full-face mask users preventing a complete seal
- Mouth breathing on nasal mask — jaw dropping during sleep breaks the seal
How to Fix It
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Re-fit the mask while lying in your usual sleep position.
Masks are often fitted while sitting upright but worn lying down. Put the mask on and lie in your usual sleep position before tightening the straps. Adjust the headgear until the mask sits comfortably with no air escaping from the edges.
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Check headgear strap tightness.
Straps should be snug but not painful — you should be able to slip two fingers under each strap. Too loose allows leaks; too tight deforms the cushion and creates new leak paths. Adjust the top and bottom straps symmetrically.
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Inspect and replace the mask cushion if worn.
Mask cushions (the soft silicone or foam part that touches the face) lose their pliability and sealing ability after 1-3 months of use. A cushion that feels hard, cracked, or deformed needs replacement. Replacement cushions are available from CPAP suppliers and are specific to your mask model.
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Clean the mask seal and face before use.
Skin oils and residue from face creams prevent the mask from forming a complete seal. Wash the mask cushion with mild soap and water daily. Wash your face before putting on the mask at night — removing skin oils dramatically improves the seal.
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Try a different mask style if leaks persist.
Some face shapes are not compatible with certain mask designs. Nasal pillow masks fit differently from full-face masks. Ask your CPAP supplier for a mask fitting appointment — most providers offer trial periods on mask styles.
Frequently Asked Questions
How much mask leak is acceptable with CPAP?
ResMed's guideline is less than 24 litres per minute total leak (shown in the myAir app or the machine's daily report). Some leakage is normal and expected. Leaks above 24 L/min reduce therapy effectiveness and should be addressed. Leaks above 40 L/min can render CPAP therapy ineffective.
Why does my mask only leak when I am asleep but not when I first put it on?
When you fall asleep, facial muscles relax and the jaw can drop, breaking the mask seal from underneath. Sleeping position changes also alter how the mask sits. This is the most common cause of leaks that are not present during fitting. A chin strap can help with jaw drop; a full-face mask is more robust to position changes than a nasal mask.