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GoodKnight H2O Heated Humidifier

BY Puritan Bennett  |  Item #Y-GKH2O-NA
(138) Read Reviews

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How to Clean and Maintain your CPAP Equipment
Rainout, Causes & Solutions
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Learn More About This Product

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.

User Manual:

The user manual included with this humidifier can be viewed and downloaded here: Goodknight Humidifier.

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

Are prescriptions required for mask, machine, humidifier, and EPAP purchases?

Yes. Federal law requires we have a valid prescription on file before we ship your mask, machine, humidifier, or EPAP therapy, including Provent and Bongo RX. You will also need a prescription to purchase the Nightbalance POSA device.

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: 713.541.7377
  • Email your prescription to
  • Upload your prescription in your account, under the Prescriptions Section
  • Ask your doctor to fill out our prescription form. We have both a standard prescription form and an EPAP prescription form.

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:

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

Here are some of the integrated humidifiers we carry:

DreamStation Heated Humidifier
Transcend Heated Humidifier
IntelliPAP 2 Heated Humidifier with Pulse Dose Humidification
PR System One 60 Series Heated Tube Humidifier with Heated Tube
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
Here are some other machines we carry with built-in humidifiers:

AirSense™ 10 CPAP Machine with HumidAir™ Heated Humidifier
AirSense™ 10 AutoSet CPAP Machine with HumidAir™ Heated Humidifier
iCH Auto CPAP Machine with PVA and Built-In Heated Humidifier
+ See More
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 temperature 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 Hybernite Heated Rainout Control System.

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

Here are some items that can help with caring for your humidifier:

CleanSmart CPAP Disinfectant Spray

Control III Disinfectant CPAP Cleaning Solution - 16 oz Concentrate

Control III Disinfectant CPAP Cleaning Solution - Home Care Kit

Hurricane CPAP Equipment Dryer

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

Here are some of our top selling humidifiers:

PR System One 60 Series Heated Tube Humidifier with Heated Tube
Transcend Heated Humidifier
XT Heated Humidifier
+ See More 100% Price Protection Guarantee

When you shop with us, we want you to be confident that you are receiving the best available price. If this items goes on sale or you spot an online or retail competitor with a lower price within seven days of your purchase, let us know, and we will credit you the difference.

"Super helpful, fast shipping, friendly assistance, great selection, I love this company."

- Verified Customer, 10/25/22



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Customer Reviews

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4.5 138 Reviews
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Very Nice Humidifier

Verified purchase | Aug. 17, 2011 | Verified Customer
Bought this Humidifier in Nov 2010 just after spending a week in the dry Colorado mountain air...wish I had it in CO. Works great, unfortunitly my goodkight cpap has since died and it can't be fixed...time for a new unit.
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Verified purchase | Mar. 12, 2010 | Verified Customer
The CPAP Goodknight humidifier looked as if it would be a godsend. Unfortunately, it leaks so I can't use it. Rats. The built in rubber gasket on the base is slightly irregular, hence the plastic top does not snuggly engage.
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goodnight h20

Verified purchase | Feb. 16, 2010 | Verified Customer
I am getting much better nights sleep with the goodnight h20 heated humidifier, glad i purchased this unit for my cpap 420g machine!!!
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I'm hoping this is great

Verified purchase | Aug. 08, 2009 | Verified Customer
I was initially excited about the compact size and integration of this humidifier. But my first one leaked almost every night(over three weeks use). After a very helpful and prompt warrenty replacement,the new chamber seems to work well(after three nights use). Currently this humidifier and cpap are much quieter than my previous ones.
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So Far So Good

Verified purchase | Jul. 29, 2009 | Verified Customer
This is the first humidifier I have had since my first CPAP machine about 10 years ago. What a difference. Compact and easy to clean. Seems to work well. Easy to connect. We will see what happens when winter comes and the dry heat is on.
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CPAP Humidifier

Verified purchase | May. 05, 2009 | Verified Customer
The GoodKnight H20 Heated Humidifier works as expected and the results are very good! No more dryness or hoarseness. I am very pleased and only wished I would have purchased one much sooner. I strongly encourage other GoodKnight users to make the purchase for their health and comfort.
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