CPAP Humidifier Parts & Water Chambers

CPAP Humidifier Guide

What's the difference between a standard and a cleanable CPAP water chamber?

Standard (or disposable) water chambers are designed to be replaced periodically — typically every six to twelve months — rather than deep cleaned. They're lower cost and straightforward to swap out. Cleanable or reusable chambers are built from more robust materials and can be thoroughly washed and dried for ongoing use, making them more economical over time. ResMed offers both options for the AirSense 10 (the HumidAir Standard Tub and the HumidAir Cleanable Tub), so it's worth considering how frequently you want to replace versus clean your chamber when choosing between them. The right choice depends on your preference for convenience versus longevity.

What water should I use in my CPAP humidifier?

Distilled water is the recommended choice for your CPAP humidifier. Because it has had minerals, impurities, and contaminants removed through the distillation process, it won't leave mineral deposits or white residue inside your humidifier chamber, and it reduces the risk of bacteria or mould growth over time. Distilled water is widely available at supermarkets such as Coles and Woolworths and many independent grocery stores, pharmacies and even some hardware stores across Australia, usually at a low cost per litre.

Here's a quick guide to how common water types compare:

Demineralised water is a good alternative and, depending on the purification process used, can be just as pure as distilled — or even purer. High-purity processes such as reverse osmosis combined with deionisation (RO + DI) can achieve lower total dissolved solids than standard distillation, and some advanced methods also remove volatile organic compounds that distillation can occasionally miss. However, as "demineralised" covers a wide range of processes, distilled water remains the more consistent and reliable choice when buying off the shelf, where you can't always tell how the water was treated.

Boiled tap water that has been allowed to cool is safer than unboiled tap water — boiling kills bacteria and microorganisms — but it is not equivalent to distilled water. Boiling does not remove dissolved minerals, so you'll still get the same buildup in your humidifier chamber over time. It's a reasonable short-term fix in a pinch, but shouldn't become a regular habit.

Still bottled water (including spring water) might seem like a clean option, but it typically still contains naturally occurring minerals and is not ideal for regular use in a humidifier.

Tap water is not recommended. Even if your local tap water is safe to drink, it contains dissolved minerals that will gradually build up inside your humidifier chamber, shorten its lifespan, and could potentially harbour microorganisms that get carried into your airways during therapy.

If you ever run out of distilled water, boiled tap water that has been allowed to cool is the next best option — it won't eliminate mineral buildup, but it at least removes bacteria and microorganisms. If boiling isn't practical, running your CPAP for a single night without water — using the humidifier dry or switching humidification off temporarily — is preferable to using unboiled tap water. Either way, get back to distilled water as soon as possible and clean your chamber thoroughly before refilling.

What is HumidX, and do I need it for my AirMini?

HumidX and HumidX Plus are waterless humidification cartridges designed exclusively for the ResMed AirMini travel CPAP machine. Unlike a traditional water chamber, HumidX uses heat and moisture exchange technology — capturing exhaled moisture and returning it to the next breath — with no water required. This makes it ideal for travel, camping, or any situation where carrying or accessing distilled water isn't practical. HumidX suits nasal and nasal pillow masks; HumidX Plus is designed for full face masks and provides a higher level of humidification. Importantly, HumidX is only compatible with masks that connect via the AirMini's integrated connector system — either AirMini-specific mask setup packs, or select ResMed masks used with a compatible AirMini setup tube kit. Standard masks connected via the ZephAir universal hose adapter do not support HumidX humidification. Note that HumidX is only compatible with the AirMini — standard CPAP machines use conventional water chambers.