Power and travel
Waterless humidification (HME)
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 that have no humidifier.
Why it helps
Travel machines such as the ResMed AirMini have no water humidifier. An HME fills the gap without water or power. ResMed describes its HumidX as capturing heat and moisture as you exhale and releasing it when you inhale, and says that in a typical dry overnight environment (16 to 22 C, 20 to 30% relative humidity) it provides air of 70 to 80% relative humidity. Because it needs no power, it also helps a battery last longer.
How to choose
HMEs are system specific. ResMed's HumidX and HumidX Plus are only compatible with AirFit N20, AirTouch N20, AirFit N30 and the AirFit P10 for AirMini masks, and HumidX F20 only with AirFit F20 and AirTouch F20 masks. HumidX Plus is designed for very dry climates and high altitude, such as aircraft. Buy the version listed for your machine and mask.
ResMed says HumidX must be changed every 30 days. An HME relies on your exhaled breath, so mask or mouth leaks reduce how well it works. It is not a substitute for a heated humidifier if your clinician has told you that you need one.
Frequently asked questions
Does the AirMini have a humidifier?
No water humidifier. It uses waterless HumidX heat and moisture exchangers that fit specific compatible masks.
How often do I replace a HumidX?
ResMed says HumidX must be changed every 30 days.
Can I use an HME with my regular home CPAP?
HumidX is designed for the AirMini system and its listed masks. For other machines, check with the manufacturer or your supplier whether a compatible HME exists.
Sources
Last reviewed October 11, 2026. How we research · Report an error