A new CPAP at typical pressure runs at about 27 decibels — quieter than a refrigerator, quieter than rainfall, quieter than most ceiling fans. If yours has gotten loud enough that your partner notices, the cause is almost never the machine itself. Six things account for nearly every "my CPAP is loud" complaint. Here they are, in roughly the order you should check them.
The most common cause
A clogged filter forces the motor to work harder to pull air through the restriction. The motor noise rises, and the airflow develops a "wheeze" you can hear from across the room. Replace the filter — the noise often disappears the same night.
1. The filter is overdue
This is the most common cause and the cheapest fix. As a filter loads up with airborne particulates, the motor has to spin faster and work harder to push the same volume of air. The result: a low-frequency hum becomes a higher-frequency whine, and the airflow itself develops a faint hiss as it passes the restricted filter.
If you don't remember the last time you replaced the filter, it's overdue. Standard disposable filters should be replaced every 2 weeks; hypoallergenic filters every 2 weeks; reusable foam filters every 6 months. Full guide: how often to replace CPAP filters.
2. The mask is leaking
A leaking mask creates two noise sources. First, the leaked air itself makes a soft whistling or hissing sound from the cushion seal. Second, the machine ramps up pressure to compensate — which makes the motor louder. Both compound, and what you hear is a CPAP that's measurably noisier than yesterday.
Leak sources, in order of frequency: worn cushion (over 3 months old), wrong cushion size, over-tightened headgear, mouth opening during sleep. Diagnostic walkthrough: why your CPAP mask isn't sealing.
3. The water chamber is empty or low
A running humidifier with the right water level adds white-noise-like dampening to the airflow. An empty chamber doesn't. Many users notice their CPAP is "louder" about a week after switching from humid to dry use, and conclude the machine is failing. It's not — they're just hearing the airflow without the humidifier masking effect.
Same applies if the chamber is below the minimum water line — the air doesn't pass through humidified water consistently, which makes the sound less smooth.
4. The tubing has a leak or kink
A pinhole leak in the hose — usually at the swivel connectors at either end — whistles. So does a tube kinked tight enough to restrict airflow. Both develop gradually as the tubing ages.
How to diagnose
With the machine running and mask off:
- Hold the disconnected mask end of the tube up to your ear. Listen for whistling at the swivel.
- Run your hand along the length of the tubing. Feel for any escaping air.
- Check the connection points at the machine end. Loose swivels are a common cause.
If you find a leak or the tubing is more than 6 months old, replace it. Our tubing replacements are built to OEM spec.
5. The chamber's silicone seal has degraded
Water chambers have a silicone gasket where they clip into the machine. Over 6 months of use, this gasket loses elasticity and develops a small but consistent air leak. The leak creates a faint whistling noise that gets worse when the humidifier is at higher temperatures.
Replace the chamber every 6 months regardless of how the seal looks. Our water chamber replacements are machine-specific.
6. The motor itself is failing
Last on the list because it's the rarest cause. CPAP motors are designed for 20,000+ hours of operation (about 8 years of nightly use at 7 hours/night). Modern ResMed and Philips machines almost never fail before the warranty window ends.
Signs that it really is the motor:
- Grinding or rattling sounds (as opposed to whistling or hissing — those are air leaks).
- The noise persists after you've replaced filter, cushion, hose, and chamber.
- The noise is louder than at the start of the night and worsens further as the night goes on, suggesting heat-related component drift.
If you suspect motor failure, the next step is a service center, not a replacement. Most ResMed and Philips machines have a 2-year manufacturer warranty; even out of warranty, the motor itself is repairable for a few hundred dollars rather than requiring a $800 replacement machine.
The "my CPAP got louder over a year" pattern
Long-term users frequently report that their machine has gotten gradually louder over a year. They assume it's the motor. In nearly every case we see, the actual cause is the cumulative effect of items 1, 2, and 5 — overdue filters, cushion wear, and chamber seal degradation. Replace all three (about $100 total). The noise usually returns to baseline overnight.
This is also the reason we built our replacement schedule tool. Most "machine getting louder" complaints come from missed replacements rather than machine wear. Catching them on schedule prevents the noise pattern from developing in the first place.
How quiet should it actually be?
| Machine | Specified noise | Real-world comparison |
|---|---|---|
| ResMed AirSense 11 | 27 dBA | Quieter than a refrigerator (40 dBA) |
| ResMed AirSense 10 | 26.6 dBA | Whisper-quiet |
| Philips DreamStation 2 | 27 dBA | Quieter than rainfall |
| ResMed AirMini (travel) | 30 dBA | Slightly louder, comparable to a quiet office |
These numbers are at typical pressure (around 8-10 cmH₂O). At higher pressures, all machines run louder — closer to 32-35 dBA at 15+ cmH₂O. This is normal.
The pillow trick
If after replacing supplies your machine is still loud enough to bother you (or a partner), a simple trick: place the machine on a folded towel, then on a soft bedside surface. The vibration-dampening effect of a soft base reduces audible noise meaningfully. Don't enclose the machine — air intake is on the side and needs clear room — but a soft base instead of a hard nightstand surface helps more than most $50 "CPAP silencer" accessories on the market.
Bottom line
Most CPAP noise complaints resolve with a $20 cushion, a $10 filter pack, or a $40 water chamber. Replace those first. Only after exhausting the cheap fixes is it worth investigating the motor. The machine itself is the last thing to suspect, not the first.