Click on the questions below to expand and reveal the answers...


H5i vs. H4i

Yes, this is normal operation for the H5i. There are a number of design differences between the H5i and H4i humidifiers that affect heater plate temperature. These are as follows;
H4i Humidifier H5i Humidifier
Heater plate temperature is based solely on the dial setting and remains constant if the dial setting is not changed. The heater plate temperature changes to ensure a constant moisture output. Heater plate temperature depends on the ambient (room) conditions, the humidifier setting and the air flow.
The moisture output will vary for a given dial setting, depending on ambient conditions and air flow. The moisture output for any given humidifier setting does not change, irrespective of changes in ambient conditions or air flow.
The heater plate temperature is not software controlled. The heater plate temperature is software controlled. If no flow is detected then the plate will not heat.
Yes. The water level left after use doesn’t give the best indication of unit function. As the H5i provides constant moisture output, it only uses the amount of water needed to provide the required level of moisture. If set at the same Climate Control temperature throughout the year, the H5i will use significantly less water during summer than it will during the winter.
Yes. To confirm H5i function, complete the following steps;
  1. Disconnect ClimateLine tubing and remove the water tub.
  2. While the S9 is NOT running, place your hand on the heater plate to assess the temperature of the H5i heater plate. NOTE: Do NOT place your hand on the heater plate if the H5i has been running in the 10 minutes prior to this test as it may still be hot.
  3. Set the humidifier output to 6.
  4. Place the unit in warm-up mode and allow it to run for 1 minute.
  5. Place your hand above the heater plate (without touching it) to confirm an increase in heater plate temperature. Don’t place your hand directly on the heater plate as it will be hot.
  6. Press the dial for 3 seconds to enable cooling down mode.



The setting on your humidifier will set how much moisture you receive to alleviate your symptoms. The higher the setting, the more moisture, and this is best checked first with your Clinician and user manual. If you start your setting for example at a midway point, and if your symptoms are not resolved, you may need to turn it up another setting. Continue in this manner until your symptoms are resolved. If you start to experience moisture in the mask tube, you need to turn it down, heat the room or use a ResMed Tubing Wrap.
If you are finding that you have nasal symptoms at other times of the year, then you should probably use your humidifier. The added humidification will probably increase the comfort of the air as it is more fully moisturised.
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.
The CPAP should always be placed either at the same level or above the humidifier to reduce the risk of water entering the CPAP machine. To further ensure water does not enter your CPAP machine, empty the water chamber and disconnect the humidifier from your CPAP machine before transporting it.
No, the tubing supplied with CPAP machines can withstand far higher temperatures than the heat generated by the humidifier.
If you find the air dry and irritating, then you may want to turn your humidifier on 20 minutes prior to going to bed.
A full face mask should not change the amount of water used each night. If you had a mouth leak before, you could have been losing lots of air and humidity through your mouth, in which case you should use less water now.
Mouth breathing or mouth leak. can make you use more water from your heated humidifier.  All the escaped air through the mouth (which can vary from night to night), uses up the water more quickly.

Humidification doesn't really help with OSA or UARS. It helps with side effects caused by CPAP. If you are already on CPAP treatment and experiencing nasal dryness/symptoms, then humidification should help decrease the symptoms. The nasal symptoms are due to the increased flow of air through the nasal passages. Humidification adds moisture to the air breathed and helps the nasal passages cope with the increased flow of air.

It is recommended that you wash your humidifier and tubing daily in warm water, using a mild detergent. Rinse them thoroughly with clean water and allow them to dry away from direct sunlight. Inspect the water chamber weekly for wear and deterioration. Replace the water chamber if any component has cracked, become cloudy or pitted. If you notice white powder or deposits in the water chamber: (1) Fill the water chamber to the maximum water level and mark with a solution of one part vinegar to ten parts water (2) Let the solution soak for ten minutes (3) Discard the solution and rinse the water chamber with clean water.
Using distilled water will maximise the life of the water chamber and reduce mineral deposits. However, it is ok to occasionally use tap water to clean your humidifier. Do not use: bleach, alcohol, chlorine or ammonia-based solutions; moisturising, antibacterial or glycerine based soaps; and water softening and unapproved descaling agents.


Water in my hose

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 vapour) 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 (eg, overnight), it has less capacity to carry water, so water condenses and forms droplets. There are a couple of ways to deal with this situation. (1) You can try turning your humidity level down. (2) You can 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. (3) You can run the air tubing beneath your blankets to keep it warm. Alternatively, you can cover the tube with a ResMed Tubing Wrap, aluminium foil or a tube sock. The goal is to keep the tube and its air warm.
Yes. Wrapping the hose helps to insulate your treatment air from the lower temperature of the room, reducing "rain out."



Up to 40% of PAP users experience nasal congestion and dryness of the nose and throat. These symptoms can be severe enough to prevent patients from continuing their treatment. The HumidAire 3i heated humidifier adds moisture and warmth to the air delivered by a CPAP or bilevel 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 results in mouth breathing and leaks.
Because you can adjust the level of heat, heated humidification offers greater flexibility and reduces more severe symptoms. Both nasal pillows and masks are a viable option when using humidification; however, "rainout" (moisture caused by having the humidifier turned up too high) when using nasal pillows may become more of an issue as the moisture is directed into the nostrils.



Insurance coverage can vary. Please contact your insurer directly.
If you go through your doctor and get a prescription and a letter of medical necessity (a letter that explains why you need heated humidification), it increases your chances of being reimbursed. Unfortunately, some insurance companies will not cover the cost of heated humidification.



Do you have a question you would like answered?

To speak with a ResMed Patient Advocate or report any performance concerns with your ResMed product, call sleepVantage on 1300 305 705 (Monday-Friday, 9:00am-5:00pm Eastern Standard Time).


If you have a specific, individual health concern—especially one related to your treatment—please discuss it directly with your health professional.

©2000-2013 ResMed. All rights reserved.