Supplies
CPAP Humidifiers: Settings, Water and Common Problems
A heated humidifier adds warmth and moisture to CPAP air and can reduce dry throat, nasal congestion and runny nose. Adjust the humidity and tube temperature for comfort, fill only with the water type your manual specifies, empty and clean the tub daily, and lower humidity if water collects in the hose.
What humidification does
ResMed explains that PAP air can overwhelm the body's ability to add heat and moisture, causing sore or dry throat, nasal congestion or a runny nose, and that heated humidification helps minimize these side effects.
Most current machines, including the AirSense 11 and DreamStation 2, have an integrated heated humidifier.
Finding your setting
Start at the default or automatic setting. If you wake with a dry mouth, nose or throat, raise humidity one step. If you see water in the hose or mask, lower humidity or raise tube temperature.
Mouth breathing with a nasal mask causes dryness no humidifier can fully fix; a chinstrap or full face mask may help.
Water
Philips specifies room temperature distilled water for the DreamStation 2. ResMed specifies distilled water for its HumidAir 11 Standard tub and drinking quality water for the HumidAir 11 Cleanable tub. Fill only to the max line and never with the tub attached.
The AirSense 11 tub holds 380 mL. ResMed's Air series FAQ says the machine works normally and safely if the tub runs dry, but without humidification.
Is it working?
Machines show icons when the humidifier is heating or cooling. ResMed's Air series FAQ says the sleep report on AirSense 10 and AirCurve 10 shows a smiley face icon when the humidifier is working as intended.
If the tub is not getting used up, the heater plate stays cold, or an error appears, check that the tub is seated correctly and contact your supplier or the manufacturer.
Using CPAP without humidity
Some people prefer no humidity. On ResMed Air series machines the tub or side cover must still be inserted, and humidification turned off in the menu.
For travel or battery use, turning humidity off greatly extends battery life.
Supplies that can help
Distilled water is what most CPAP humidifier chambers are meant to be filled with, because it leaves little or no mineral scale behind.
The removable water tank of a CPAP humidifier; it wears and needs replacing, especially if it cracks, clouds or leaks.
Tubing with a built-in heating wire that keeps humidified air warm all the way to the mask, which is the main fix for rainout (water droplets …
A soft strap that supports the jaw to help keep the mouth closed, used mainly with nasal and nasal pillow masks to reduce mouth leaks.
A heat and moisture exchanger (HME) that captures warmth and moisture from your breath and returns it on the next breath, used mostly with travel CPAPs …
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Frequently asked questions
What humidity setting should I use on my CPAP?
Start with the default or automatic setting and adjust one step at a time: up for dryness, down for water in the hose.
Do I have to use the humidifier on my CPAP?
No, it is optional for many people. Some machines need the empty tub or a side cover inserted to run without humidity.
Why is my CPAP humidifier not using water?
Humidity may be set low or off, the room may already be humid, or the tub may be seated wrong. If the heater seems dead, contact your supplier.
Can a CPAP humidifier cause mold?
Standing water can grow mold and bacteria. Empty and clean the tub daily as ResMed and Philips direct.
Sources
Last reviewed October 11, 2026. How we research · Report an error