Humidifier settings FAQs | ResMed
Humidifier settings
Healthcare professionals > Support > Humidifiers > Humidifier settings

Optimising my patient's humidifier settings: FAQs

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

How do I know what setting my patient should use with a PAP humidifier?

It depends which ResMed humidification system the patient is 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, your patient 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, your patient 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 your patient expresses 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 my patient change the water in the humidifier tub? It doesn’t get used up in one night.

Your patient should change the water in the humidifier tub every day, even if it doesn't get completely used up in one night.

What kind of water should my patient use with the humidifier?

With a cleanable tub, tap water is fine for everyday use. If your patient has a standard humidifier tub, we recommend distilled or deionised water.

Your patient should not use any of the following in the humidifier:

  • Bleach, alcohol, chlorine or ammonia-based solutions
  • Moisturising, antibacterial or glycerine based soaps
  • Water softening and unapproved descaling agents

These products could damage the humidifier and its function, or leave harmful residual vapours that could be inhaled if not rinsed thoroughly.

How much water should my patient's humidifier use overnight? 

There is no simple answer to this question, as 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.

My patient says that the water level in his humidifier doesn’t drop very far, even when it’s in use for a full night. Is this normal?

Yes. The amount of water left in the humidifier tub isn't the best indication of how a humidifier is functioning. As the H5i and HumidAir provide 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 during the winter.

On the AirSenseTM 10 and AirCurveTM 10 therapy devices, you have the possibility to check the humidifier status in the Sleep report screen to reassure your patients. If the smiley is green, it means that the humidifier is functional and connected. The smiley will turn red if there is a humidifier fault. You also have this status directly at your fingertips on AirView Remote Assist for the therapy devices which are activated for telemonitoring.

My patient says that the humidifier is usually almost empty in the morning and that it sometimes runs out of water during the night. What can be done? 

Different humidifiers use different amounts of water in different conditions. For example, the water delivery output from an H5i or HumidAir Heated Humidifier depends on the temperature and humidity levels in the room, the settings on the humidifier, and the therapy pressure delivered by your patient's sleep therapy device. If the room conditions change from night to night (e.g. one night the heating is turned 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 your patient is breathing through the mouth or has mask leak. Mouth breathing and mask leak both allow air to escape, and this can decrease the efficiency of the humidifier.

If mouth leak is under control or your patient is using a full face mask, try one or more of the options below:

  • ClimateLine (S9™) or ClimateLine Air (AirSense/AirCurve 10) heated tubing
  • Tubing wrap
  • Lowering the humidity level setting
  • Adding a humidifier to the room