CPAP Humidifier FAQs

A heated humidifier uses heat to warm the water to add moisture to the airstream. The heat is adjustable for more or less moisture. The warmer the air, the more moisture it can carry. Since CPAP therapy can produce nasal dryness in many patients, adding a heated humidifier to your CPAP machine can make therapy much more comfortable for most patients.

Why should I use a heated humidifier?

Many CPAP users experience nasal congestion and dryness of the nose and throat. These symptoms can be severe enough to prevent patients from continuing their treatment.

A heated humidifier can add moisture and warmth to the air when delivered by a CPAP or bi-level system. This reduces symptoms of dryness and congestion, improving patient comfort and compliance.

Research also shows that nasal resistance can promote mouth breathing, which in turn leads to additional dryness. Heated humidification can prevent the large increase in nasal resistance that may result in mouth breathing and leaks.

How much water should my humidifier use in a night?

The amount of water needed varies from one humidifier to the next, from one patient to the next, and with the temperature and humidity of the bedroom.

How often should I change the water in my humidifier?

Please follow the guidelines from your manufacturer. In general, the water should be changed each night, even if don't use it all in one night.

When I use my humidifier, my tube gets water in it?

This condensation is called rainout.

If your room is cold, the warmed, humidified air hits the colder room temperature and cools. When air cools, the amount of humidity (water vapor) that it can hold is reduced, which causes the humidity to rain out.

The amount of water air can carry varies with temperature: warmer air can carry more water while cold air can carry less. As warm air becomes cooler (e.g., overnight), it has less capacity to carry water, so water condenses and forms droplets.

There are several ways to deal with this situation.

  • Try using a heated tube if available for your machine model.
  • Try turning your humidity level down.
  • Raise the temperature of your bedroom at night to lessen the difference between the room temperature and the humidifier—make sure that your bedroom window is closed.
  • Run the air tubing beneath your blankets to keep it warm. Alternatively, you can cover the tube with a tube wrap or a tube sock.

How often should I clean my humidifier chamber?

Please follow the guidelines from your manufacturer. In general;


It is recommended that you wash your water tub in warm water, using a mild detergent. Rinse thoroughly with clean water and allow them to dry away from direct sunlight.


  • Inspect the water tub for wear and deterioration.
  • Replace the water tub if any component has cracked, become cloudy or pitted.