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    GoodKnight H2O Heated Humidifier

    Product Features

    Improve Comfort and CPAP Compliance

    For CPAP patients experiencing upper airway dryness, Puritan Bennett offers a mist of relief with the GoodKnight H2O Heated Humidifier. Designed for use with the GoodKnight 420 Series CPAP System or GoodKnight 425 Bi-Level Device, the GoodKnight H2O Heated Humidifier increases air humidity, reducing patient dryness in the nose and throat. By improving comfort, it may help promote patient compliance with sleep apnea treatment. In addition, the humidifier features a small footprint that fits neatly with GoodKnight sleep therapy devices, creating the smallest, lightest, CPAP/heated humidifier on the market.

    • HumidControl Feature

      The HumidControl feature ensures a consistent temperature difference between the water and ambient air to minimize condensation in the tubing ("rain out") and keep the humidification level constant throughout the night

    • Space-saving design

      Adds only 3 inches to the length of any Goodknight 420/425 sleep therapy device.

    • Easy to Clean

      Comes with a detachable, dishwasher safe water chamber for trouble-free maintenance.

    • Each to use

      Features a rotary button that allows patients to adjust heating level.


    This Product Includes...

    • Humidifier
    • Chamber
    • Power Cord
    • Coupler
    • Chamber Key

    Product Specifications

    Maximum Flow: 120 liters per minute (leak flow included)
    Pressure fall according to the flow: 0.2 cm H2O
    Service maximum pressure: 25 cm H2O
    Maximum gas temperature at the breathing circuit outlet: 106 Degrees F (41 Degrees C)
    Humidification rate: 12 mg H2O/L at 60 L/min and at the maximum setting
    Time of heating: Less than or equal to 45 minutes
    Duration necessary for the water temperature
    to reach 90% its value set, on a 23 +/i 2 Degrees C temperature basis:
    60 min.
    Dimensions (W x H x L): 6.7" x 3.7" x 11" (170 x 95 x 280 mm)
    Weight (when empty): 1.76 lb
    Operational volume: 213 cm cubed (minimum volume of gas in the chamber)
    Usable volume of the water chamber: 350 mL
    Maximum level of liquid: indicated on the chamber
    Power Characteristics: AC power cord supplies power to humidifier only; sleep therapy device has separate power cord
    Input voltage: 100 VAC (+/- 15%), 120 VAC (+/-10%/-20%),230 VAC (+/- 10%), 50/60 Hz (Power supply cord adaptable in accordance with the country)
    Temperature: -4 Deg C to +140 Deg F (-20 Deg C to +60 Deg C)
    Relative humidity: between 15% and 95% without condensation
    Relative pressure range: 700 hPa to 1060 hPa
    Maximum temperature: +5 Deg C to +40 Deg C
    Relative humidity: between 15% and 95% without condensation
    Relative pressure range: 700 hPa to 1060 hPa always offers these services:

    • 8 am to 10 pm CST Toll Free Phone and Email Support
    • 24 hour access to our Support Forum
    • Learning Center for information on sleep apnea and cpap equipment
    • Consumer Purchasing Trends Reports
    • Warranty Services for all items purchased through
    • Insurance Compliant Invoices
    • Free Prescription Request System

    Important Tips

    If your cord is worn or lost, use the Power Cord for Respironics and Resmed S8 machines, part number 18AWGX2C, as the replacement cord.

    CPAP Video & FAQ

    Frequently Asked Questions (FAQs)

    Are prescriptions required for mask, machine and/or humidifier purchases?
    Yes. Federal law requires we have a valid prescription on file before we ship your mask, machine and/or humidifier.

    We provide many easy ways to get your prescription:
    • We can request your prescription for you! When you checkout, just let us know you would like us to request your prescription, or you can log into your account to have us request your prescription.
    • Fax your prescription to our toll free fax number: 866.353.2727, or our international fax number: 713.541.7370
    • Email your prescription to
    • Upload your prescription in your account, under the Prescriptions Section
    For more information on prescriptions, please see our Prescription Section of the Learning Center.
    What is a heated humidifier?
    A heated humidifier uses heat to warm the water to add moisture to the airstream. The heat is adjustable for more or less moisture. A heated humidifier water chamber is much smaller than a passover humidifier water chamber.

    In our experience, it is common for CPAP users to report that their therapy is greatly enhanced by the use of a heated humidifier.

    There are three types of heated humidifiers:
    • Stand Alone Humidifiers
    • Integrated Humidifiers
    • Built In Humidifiers
    What is a passover humidifier?
    A passover humidifier uses a chamber of room temperature water with the CPAP to add moisture to the airflow and reduce irritation to the nasal passages.

    Air flows from the CPAP through a short hose to the humidifier chamber where the air "passes over" the water to pick up whatever moisture it can. The air then flows into the six foot hose to the mask.

    Passover humidifiers may provide sufficient moisture with CPAPs set at lower-end pressures. However, if the moisture is not sufficient there is no way to increase the amount of moisture added. The water is room temperature. In cold climates, the water temperature will drop causing the CPAP air to become very cold, and causing the amount of moisture to be reduced.
    What is an integrated humidifier?
    An integrated humidifier is used with a specific CPAP and fits directly onto the machine. For most heated humidifiers, this design eliminates the need for a second hose as well as a second power cord.

    An advantage of an integrated humidifier is that it works very closely with the CPAP machine to deliver humidification. Also, an integrated humidifier is a compact unit that uses fewer parts to provide moisture to the user.

    A disadvantage of the integrated humidifier is the user will receive less moisture when it is used with a passover humidifier. The smaller surface area effects the amount of moisture produced. Also, a integrated humidifier will only function with the CPAP for which it was designed.

    You can see if your machine has an integrated humidifier option by reviewing our Compare Charts.

    An example of an integrated humidifier is the PR System One Heated Humidifier as seen below attached to a machine in the PR System One line. PR System One Heated Humidifier
    What is a built in humidifier?
    A "built in" humidifier is designed as a part of the CPAP machine and cannot be removed or separated from the CPAP machine. As with an integrated humidifier, the design eliminates the need for a second hose or power cord. The water chamber can be removed for cleaning or replacement purposes.

    The advantage of a "built-in" humidifier is its compact shape, which operates on fewer parts. This integrated design helps to ensure optimum moisturized comfort and effectiveness when CPAP therapy and humidification are used together. Also, it allows an option for the humidification to be turned off while the CPAP is blowing.

    A disadvantage is that a built in humidifier may produce less moisture if used as passover because the surface area is typically smaller. Also, since the humidifier is "built in" to the machine, detaching it is not an option. This can be an issue for frequent travelers. Lastly, if the machine or humidifier stops working, the entire unit must be sent in for repair or replacement, not just the component that failed.

    An example of a machine with a built in humidifier is the ICON Auto CPAP Machine with Built In Heated Humidifier and SensAwake as seen below. ICON Auto CPAP Machine with Built In Heated Humidifier and SensAwake
    What is a stand alone humidifier?
    A stand alone humidifier is a component that will work with any CPAP and does not attach directly to the machine. It has its own power cord and a short hose to connect it to the CPAP. Generally it will sit next to the CPAP machine and is slightly larger than an integrated humidifier.

    The advantage of a stand alone humidifier is the fact that it may be used with any CPAP machine.

    The main disadvantages are that the size is often larger than either a "built in" or integrated humidifier and that a short hose is needed to connect it to the CPAP machine.

    An example of a stand alone humidifier is the Fisher & Paykel HC150 Heated Humidifier as seen below. HC150 Heated Humidifier
    What is rainout?
    Rainout is the accumulation of water in a CPAP tube due to warm moist air cooling and condensing on its way from your CPAP machine to your CPAP mask.

    The image below from Fisher & Paykel explains how rainout is formed. Warm, moist air leaves the heated humidifier and travels through the CPAP tube. As air flows through the tube, the temperature of the room causes the tube to cool. As the tube cools, the air inside releases its moisture, and creates condensation in the hose.

    Solutions to rainout include:
    • Raise the temperature of your bedroom.
    • Keep your CPAP machine at the same level as your bed.
    • Insulate your tubing with a hose cover like Snugglehose.
    • Reduce the tempurature setting on your heated humidifier.
    • Purchase a CPAP machine with a rainout reduction comfort feature.
    • Some machine systems offer a compatible heated CPAP hose which maintains the temperature from the machine all the way to the mask, reducing the occurrence of rainout. The list of available heated hoses can be found here: Hoses With Heating Coils.
    • If your machines uses a standard hose, consider the ComfortLine Heated Tubing Kit.

    Conventional Humidification
    How do I care for my humidifier?
    To care for your humidifier simply empty and clean the water tank each morning. Only distilled water should be used in the humidifier to avoid mineral deposit build up. S9 Dishwasher Safe Humidifier Chamber
    Why do I need to use distilled water with in my humidifier chamber?
    Use distilled water to help keep the humidifier chamber clean and mineral deposit free. Tap water should not be used as it will leave hard white mineral deposits in the chamber as the water evaporates, or it may lead to mold growth. Cases of lung disease have been connected to using contaminated well water in a CPAP humidifier.* Source

    If distilled water is not available where you live, use bottled water. It will be important to clean the chamber each morning, do not leave standing water in the chamber between uses.
    What does a humidifier prescription need to say?
    A humidifier prescription must contain all of the following information:
    • One of the following words or phrases: "CPAP Humidifier", "Humidifier", "HH", "CPAP Supplies", "CPAP Mask", "CPAP", "Continuous Positive Airway Pressure", "APAP", "AutoPAP", "AutoSet", "Auto CPAP", "Auto Adjusting CPAP", "Self Adjusting CPAP", "BiPAP", "BiLevel", "VPAP", "BiPAP Auto", "BiPAP ST", "Synchrony ST", "VPAP ST"
    • Your physician's contact information
    • Your physician's signature
    • The patient's full name
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