ResMed HumidX Plus Waterless Humidifier for AirMini

The HumidX Plus is the gray cartridge in the AirMini range, and it hands back more of your own breath than the blue one does. It is built for air that has very little moisture of its own to give.

ResMed names high altitude and aircraft cabins as the conditions it is optimized for, and winter heating does the same thing to a bedroom. It fits the AirFit P10 for AirMini, the AirFit N30 for AirMini, and the AirFit N20 connector.

Key Features:

• When to step up: ResMed points at the Plus when your mask seals well and you are still waking up dry.
• When to step back: Beads of water forming anywhere between the vent module and your face mean the room wanted the blue one.
• Same thirty day clock: Opening the sealed pack starts the count, whether or not you end up using it every single night.
• Told apart by color: Plus is gray and standard HumidX is blue, which matters because the two cartridges are the same shape.
• Nasal and pillows only: It seats in the vent module that the P10, N30 and N20 AirMini connectors use, and nowhere else.
• Worth keeping both: Ambient humidity moves with the season, so most people end up owning one of each and swapping.

The HumidX Plus is ideal for anyone who travels to dry places, sleeps at altitude, or runs central heating through a long winter. It is the step up from the blue cartridge rather than a replacement for it, and both take the same slot.

Note: The Plus is not an upgrade to buy by default. In an ordinary bedroom it can put more moisture into the air than you want, and the fix for that is the blue HumidX.

📄 Download the ResMed HumidX Fact Sheet

What actually makes air feel dry

Relative humidity is the share of the moisture the air could hold at a given temperature that it is actually carrying. Heat a bedroom in January and the air can suddenly hold far more than it did outside, so the same amount of water now counts for much less. That is why a radiator dries you out even though nothing was removed.

Altitude and aircraft cabins reach the same place by a different route. Cabin air is drawn from outside at cruising height where there is almost no moisture in it at all, which is why a long flight leaves your nose raw. The Plus exists for those two situations, and for the handful of climates that behave like them all year.

Fitting it and looking after it

Twist the connector gently to open it, hold the cartridge by its sides with the colored face pointing down, drop it in, then push the two halves together and twist until they lock. It seats one way, and forcing it is the only way to get it wrong.

It never goes near water. ResMed is explicit that immersing one alters the therapy it delivers, so a cartridge stays dry from the moment you break the seal to the moment you throw it out. Look it over each morning for dust or damage, park it somewhere dust free while the machine is idle, and never hand one on to another person.

Here's everything that comes in the box.

• HumidX Plus cartridges in gray, 1, 3 or 6 per pack
• Sealed pack, with the thirty days starting when you open it