Humidifier Settings FAQs | ResMed
Humidifier settings
Patients and Families > Support > Humidifiers > Humidifier Settings FAQs

FAQs: How do I properly adjust my humidifier settings?

To ensure your CPAP, APAP or bilevel therapy is as effective as possible, it's important that you adjust your humidifier settings properly. Find answers to the most frequently asked questions about humidifier settings below.

How do I know what setting to use with my CPAP humidifier?

If you're not sure which setting to use, please talk to your healthcare provider or doctor, who should be able to tell you which setting to use. Your humidifier user manual is also a useful source of information.

Thereafter, it depends which ResMed humidification system you're using:

  • H5i™:
    • The H5i has added intelligence to help deliver constant humidity and minimise rainout during standard humidification. H5i humidification delivery is controlled by three inputs (ambient humidity, H5i settings and device flow) and adjusts the output to maintain consistent water delivery.
    • In general, you should start at a humidity level setting of 3 and adjust up or down by 0.5 to address any drying or rainout issues.
    • When using ClimateLine™ heated tubing, we recommend using Auto mode, which defaults to a Climate Control setting of 27°C. From there, you can adjust up and down as necessary. If using ClimateLine heated tubing in Manual mode, start with a humidity level setting of 3 and a heated tube setting of 27°C.
    • Adjust the humidity level up and down by 0.5 to address any drying or rainout issues, and adjust the heated tube level up and down in one-degree increments to find the most comfortable temperature setting.
  • HumidAir:
    • HumidAir technology is similar to the H5i’s one. It delivers constant humidity and minimises rainout during standard humidification thanks to its different sensors.
    • On HumidAir, we recommend that you start at a humidity level of 4 and adjust up or down by 1 to address any issues.
    • ClimateControl Auto mode is the recommended mode to use when using ClimateLine Air heated tube. It is the default mode, set to an air temperature at the mask of 27°C and 85% relative humidity. If you feel the need to decrease or increase the temperature, you need to switch to Manual mode, and carefully look at the humidity level as well as the heated tube temperature to help prevent rainout.

How often should I change the water in the humidifier tub? I never seem to use it all in one night.

You should change the water in the humidifier tub every day, even if you don't use it all in one night.

How much water should my humidifier use overnight?       

A number of factors determine how much water a humidifier will use. These include the model of humidifier, the temperature and humidity of the room, the settings of the humidifier, and the characteristics of the individual patient.

The water level in my humidifier doesn’t seem to drop very far, even when I use it for a full night. Is this normal?

Yes. The amount of water left in the humidifier tub isn't the best indication of how your humidifier is functioning. As the H5i and HumidAir provides constant moisture output, it only uses the amount of water needed to provide the required level of moisture. If it's set at the same Climate Control temperature throughout the year, the humidifier will use significantly less water during the summer than it will during the winter.

My humidifier sometimes runs out of water during the night. Most other nights it is almost empty by the morning. What should I do?        

Different humidifiers use different amounts of water in different conditions. For example, the water delivery output from an H5i Heated Humidifier depends on the temperature and humidity levels in the room, the settings on the humidifier, and the therapy pressure delivered by your sleep therapy device. If the room conditions change from night to night (e.g., one night the heater is left on in the house, and the next night it’s turned off), this can result in different volumes of water being used.

It may also be that you’re breathing through your mouth, or have mask leak. Mouth breathing and mask leak both allow air to escape, which can decrease the efficiency of the humidifier.

If mouth leak is under control or you are using a full face mask, trying one or more of the options below may help:

  • ClimateLine (S9TM) or ClimateLine Air (AirSenseTM/AirCurveTM) heated tubing
  • Tubing wrap
  • Lowering your humidity level setting
  • Adding a humidifier to the room

If you are concerned about the amount of water that your humidifier is using, or if you are worried that your device is not operating properly, please contact your care provider.