A CPAP humidifier adds warmth and moisture to the pressurized air before it reaches your mask, which is what stops the dry mouth, sore throat and nosebleeds that make people give up on therapy in the first month. This guide explains how CPAP humidifiers work, the difference between heated and passover humidification, how to fill, clean and replace the water chamber, and how to fix the two problems that come with humidified air: rainout and odours. The chambers and tubing named here are in our CPAP humidifiers and water chambers category and ship without a prescription.
Nearly every home machine sold in Canada today, including the AirSense 11, AirSense 10 and DreamStation 2, has a heated humidifier built in. The question is rarely whether to get one; it is how to set it, how to look after the chamber, and what to do when the hose starts gurgling at 3 a.m. Those are the questions this guide answers, and the consumables that go with the humidifier are all under CPAP supplies.
How a CPAP Humidifier Works
Room air is dry once it is compressed and blown through a mask for seven hours, and dry air pulls moisture out of the nose, mouth and throat. The humidifier sits between the blower and the tube: air passes over a chamber of water, picks up moisture, and carries it to the mask. Alberta Health Services’ sleep centre notes that most people need a few weeks before they can sleep comfortably with CPAP, and that nasal congestion makes CPAP harder to use, in its guide to treating obstructive sleep apnea. Humidification is the main tool for getting through those weeks.
The symptoms a humidifier addresses:
- Dry or irritated nasal passages and frequent nosebleeds
- Dry mouth, especially for people who breathe through the mouth at night
- Congestion and sinus irritation
- Sore or scratchy throat on waking
Needs change with the seasons. A Canadian winter with the furnace running calls for more humidity than a humid July night, and some people find after a few months that they need less than they started with. If you wake dry, turn the setting up a notch; if you wake to water in the hose, turn it down.
Built-in, integrated and standalone
Current machines have the humidifier built into the body with a chamber that slides in from the side; that is the AirSense 10 and 11, the DreamStation 2 and the Löwenstein prismaSMART. Older machines used an integrated humidifier that clipped on as a separate module made for that model. Standalone humidifiers that connect by tubing to any machine still exist but are rarely sold with new equipment, since they need their own power and take up more space. If you are buying today, the humidifier comes with the machine; what you will buy later is the chamber.
Heated versus passover
A passover humidifier lets air cross room-temperature water and picks up what moisture it can. A heated humidifier warms the water on a plate under the chamber, which puts more moisture into the air and warms it. Every built-in humidifier on a current home machine is heated, with a setting you adjust on the screen: 1 to 8 on the AirSense 11, 1 to 5 on the DreamStation 2. Passover is now mostly a travel-machine feature; the AirSense AirMini uses a waterless HumidX insert that recovers moisture from your own breath instead of a chamber.
Filling, Cleaning and Replacing the Water Chamber
The chamber (also called the tub or reservoir) is the only humidifier part you handle daily, and how you treat it decides how long it lasts.
Use distilled water. Tap water leaves mineral scale on the heating plate and inside the chamber, which clouds the plastic, reduces output and is hard to remove once it sets. Distilled water is sold at every grocery store and pharmacy in Canada. Fill to the line on the side of the chamber, never above it, and keep the machine below the level of your head so water drains back toward the chamber rather than toward the mask.
Every morning, empty the chamber, rinse it with warm water and a drop of mild unscented soap, and leave it to air-dry out of direct sunlight. Standing water grows film within a day or two. Once a week, soak it for 20 to 30 minutes in one part white vinegar to three parts warm water, rinse well and dry. The vinegar lifts early scale and clears odours. Avoid dish soaps with fragrance, bleach, and anything abrasive; they leave residue you will then breathe. Our cleaning and maintenance guide covers the rest of the system on the same schedule.
Replace the chamber every six months, or sooner if it clouds, cracks, leaks at the seal, or scale will not come off. A cracked chamber can leak into the machine. For the AirSense 11 the replacement is the AirSense 11 humidifier chamber, or the AirSense 11 cleanable chamber if you want a stainless-base version you can take apart to wash. Fisher & Paykel machines use the HC234 chamber. Chambers are model-specific, so match the machine name before ordering; the full list is under CPAP humidifiers and chambers.
The heating plate under the chamber is part of the machine and should last its whole life if you use distilled water. If the water stops warming, that is a warranty call, not a repair you should attempt.
Fixing Rainout
Rainout is warm, humid air cooling inside the tube and condensing. You hear it as gurgling and feel it as water in the mask. It happens most in a cool bedroom, which describes most Canadian bedrooms from October to April. Left alone, the moisture pools against your skin and breaks the mask seal, which is why it shows up alongside mask irritation and leaks. Three fixes, from most to least effective:
- Heated tubing. A heated hose keeps the air warm all the way to the mask so it never cools enough to condense, and on ResMed and Philips machines it switches on automatic climate control, which adjusts humidifier and tube temperature together. Heated tubing is model-specific: the ClimateLineAir 11 for the AirSense 11, the ClimateLineAir for the AirSense 10. Our guide to choosing CPAP tubing covers the fit.
- A hose cover. A fleece hose cover insulates a standard tube. It does not warm the air, but it slows the cooling enough to stop most condensation and costs a fraction of a heated hose.
- Lower the humidity one step. Less moisture in the air means less to condense. Try one notch at a time until the hose stays dry without your mouth going dry.
Travelling With a Humidifier
Every current machine runs without water in the chamber, and most let you turn the humidifier off in the settings, so for a short trip the simplest answer is to empty the chamber, pack the machine, and go. Expect drier air for a few nights. For longer trips, pack enough distilled water for the first night or two and buy more at your destination; it is sold at pharmacies and grocery stores across Canada. If you travel often, a dedicated travel CPAP machine with waterless humidification removes the water question entirely; our travel CPAP guide compares the options. Most insurers treat a travel unit as a second machine and will not fund it, so plan on it being out of pocket.
Keep Oils and Scents Out of the Chamber
A CPAP humidifier is not a room diffuser. Aromatherapy oils, scented water additives and perfumed soaps cling to the plastic and the silicone seal, and the machine then aerosolizes them straight into your airway for hours. Inhaled oil droplets irritate the lungs and the residue degrades the chamber. Clean with unscented soap, deodorize with the vinegar soak, and if you want a scent in the bedroom, use a candle or a diffuser on the other side of the room.
Chamber clouded, cracked or past six months?
The replacements for the machine most of our customers own, plus the fix for rainout. No prescription required, and orders over $150 ship free across Canada.
Different machine? Browse all CPAP humidifiers and water chambers or the full CPAP supplies hub.
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Sign Up Free →Frequently Asked Questions
Do I need a humidifier with my CPAP?
Most people do, at least through the first weeks and through winter. If you wake with a dry mouth, sore throat or nosebleeds, the humidifier is the first thing to adjust. Some people in humid climates or after months of therapy run it low or off and are comfortable.
Can I use tap water in a CPAP humidifier?
Distilled water is the right choice. Tap water leaves mineral scale that clouds the chamber and coats the heating plate. A night or two of tap or bottled water while travelling will not harm anything if you clean the chamber afterward.
Why is there water in my CPAP hose?
That is rainout: humidified air cooling and condensing inside the tube. Heated tubing stops it; a hose cover reduces it; lowering the humidity one step helps if you do not want to change the tube.
How often should I replace the water chamber?
Every six months, or sooner if it clouds, cracks, leaks or scale will not clean off. Most Canadian extended health plans fund a replacement chamber on that schedule. Chambers are model-specific, so order the one made for your machine.
Do I need a prescription to buy a humidifier chamber in Canada?
No. Only the machine needs a prescription. Chambers, tubing, filters and masks ship without one.
Final Thoughts on CPAP Humidifiers
The humidifier is the part of a CPAP machine that makes the therapy tolerable, and it asks very little in return: distilled water, a rinse each morning, a vinegar soak each week, and a new chamber twice a year. Get those four habits in place and the dryness that drives people away from CPAP mostly stops being a problem.
If you are unsure which chamber fits your machine or whether heated tubing would help, tell us the model and we will point you to the right part. Call 1-855-492-3316 or email [email protected], seven days a week from 9 AM to 9 PM. Orders over $150 ship free across Canada.
This guide is here for general information and is not a substitute for medical advice. Follow your prescription and your care team’s instructions for pressure and humidity settings, and consult your machine’s manual for chamber-specific cleaning and replacement guidance.
