Differences between humidifiers from ResMed

What are the differences between ResMed’s H5i™, H4i™ and HumidAire 3i™ humidifiers? Find answers to your most frequently asked questions about ResMed humidifiers here.

Q. What are the main design changes between the H5i and H4i that affect heater plate temperature? My H5i humidifier heater plate doesn’t seem to get as hot as the heater plate on the H4i. Is this normal?

A. Yes, this is normal operation for the H5i. There are a number of differences between the H5i and H4i humidifiers that cause this:

  • H4i: Heater plate temperature is based solely on the dial setting and remains constant if the dial setting is not changed.            
  • H5i: The heater plate temperature changes to ensure a constant humidity level. Heater plate temperature depends on the ambient (room) conditions, the humidifier setting and the air flow.
  • H4i: The moisture output will vary for a given dial setting, depending on ambient conditions and air flow.
  • H5i: The moisture output for any given humidifier setting does not change, irrespective of changes in ambient conditions or air flow.
  • H4i: The heater plate temperature is not software controlled.
  • H5i: The heater plate temperature is software controlled. If no flow is detected then the plate will not heat.

Q. The water level in my H5i doesn’t seem to drop very far, even when I use it for a full night. Is this normal?

A. Yes. The water level that’s left after use doesn’t give the best indication of how your humidifier is functioning. 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.

Q. Is there a simple way for me to check that my H5i heater plate is working properly?

A. Yes. To confirm whether your H5i is functioning properly, complete the following steps;

  • Disconnect the ClimateLine™ tubing and remove the water tub.
  • 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 within the last 10 minutes—it could still be hot.
  • Set the humidifier output to 6.
  • Place the unit in warm-up mode and let it run for 1 minute.
  • 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.
  • Press the dial for three seconds to enable cooling down mode.
  • Check out this video to get more info on whether your H5i is working properly.

Q. What are the differences between the H4i and HumidAire 3i humidifiers?        

A. Both the H4i and HumidAire 3i humidifiers are high-quality devices designed to improve your sleep apnoea therapy. However, the H4i is the newer and more advanced model, providing 30 percent more humidification than HumidAire 3i. H4i also has 65 mL more water capacity to support humidification needs at higher flow rates and pressures.

Both humidifiers offer user-friendly humidity controls — simply start at setting 3, then customize for comfort. Both also have a snap-top cover that’s easy to use, set up and refill.

Q. How can I tell the H4i and HumidAire 3i humidifiers apart?

A. The H4i humidifier doesn’t have a ResMed logo on the front panel; rather, it’s located on the bottom of the device. The H4i also has a larger heater plate and offers a thumb notch on the rounded top cover. The HumidAire 3i’s cover is more slanted and does not offer a thumb notch.

Q. Can the H4i water tub be used with the HumidAire 3i docking station?

A. Yes. The H4i water tub be used with the HumidAire 3i docking station by replacing the top cover and seal of the 3i with the new top cover and seal, H4i water tub and cleaning plug. You can use either the standard or cleanable H4i water tubs on a HumidAire 3i docking station. However, you cannot use a HumidAire 3i water tub on the H4i docking station.

Q. Will I get better humidification from my HumidAire 3i if I use the H4i conversion kit?

A. The humidification levels with H4i tubs used on a HumidAire 3i system will be equal to using the HumidAire 3i tubs. However, you’ll have the ability to take advantage of the larger 65mL water capacity for higher pressures and bilevel therapy. The H4i tubs are also offered at a lower cost than HumidAire 3i tubs.

Q. Can I buy the entire H4i humidifier separately or only in co-packaging with a flow generator?

A. Yes. You can purchase the H4i humidification system as a separate purchase. You may also purchase the H4i with a “cleanable” water tub separately.

Q. What do I need to buy to use an H4i cleanable tub on the HumidAire 3i docking station?

A. To use the cleanable tubs while using the HumidAire 3i docking station, you must purchase the flip-top cover and seal. You may then purchase the cleanable tub separately as needed (PN 26958).

Do you have a question about the differences among ResMed humidifiers that isn’t addressed here? Contact a ResMed accredited outlet, click here to submit an online inquiry.

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