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- ResMed
HumidAire H4i™ Heated Humidifier
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HumidAire H4i Heated Humidifier Overview
The HumidAire H4i™ Heated Humidifier by ResMed is compatible with the S8 line of machines. It features improved performance and capacity versus its predecessor, the H3i.
The HumidAire 4i provides relief from symptoms such as dry nose or mouth, irritation, and congestion sometimes related to CPAP therapy without jeopardizing performance or convenience.
Nasal CPAP users generally experience congestion and dryness of the nose and throat. The warm moist air that humidification provides has been proven to relieve symptoms of dryness and can make therapy more comfortable.
Fliptop lid design - water chamber fills without removing the tubing.
Small design - unobtrusive on the nightstand and easy to pack for travel.
Seamless integrated unit - snaps onto the CPAP machine whenever needed.
390 ml capacity - very efficient humidification with a high volume.
Powered by ResMed S8 and S8 II Machines - no extra outlets or power supply necessary.
Simple Dial Control - easy to utilize in darkness and fast to respond.
This Product Includes...
- Humidifier
- Chamber
Maximum Heater Plate Temperature: 185°F (85°C)
Temperature Cut-Out: 199°F (93°C)
Dimensions of Chamber and Docking Station: 5" x 6.7" x 8.3" (118mm x 164mm x 145mm)
Weight of Docking Station and Unfilled Water Chamber: 1.6 lb (732g)
Water Capacity: 390ml to Max Fill Line
Power Supply Input Range: 100-240V, 50/60Hz; 110V, 400Hz; 2.5A < 140 VA (110 W) (maximum power consumption)
Maximum Heater Element Power: 85 W
Docking Station Materials: Flame Retardant Engineering Thermoplastic,Plated Cast Aluminum
Water Chamber Materials: Injection Molded Plastic, Stainless Steel
Operating Temperature 41°F to 95°F
Operating Humidity 10-95% Non-Condensing
Storage and Transport Temperature -4°F to 140°F
Storage and Transport Humidity 10-95% Non-Condensing
IEC 60601-1 Classification: Class II (Double Insulation); Type CF
Electromagnetic Compatibility: Product complies with all applicable electromagnetic compatibility requirements (EMC) according to IEC60601-1-2, for residential commercial and light industry environments.
*Consult the medical department of the carrier before using on aircraft.
Warranty Length:
- Heated Humidifier - 1 Year
- Water Chamber - 90 Days
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Manufacturer Note
- Some product images supplied by ResMed © ResMed 2010 Used with Permission.
- All services provided by CPAP.com, including advertisement, ordering, sale, delivery, instruction, and setup of the products are performed solely by CPAP.com and independently of the manufacturer.
- A valid prescription is required for the purchase of this product.
This humidifier cannot be run off of 12 volt DC power. If a machine is powered by 12 volts, the heated humidifier will not run. A 110 volt pure sine inverter hooked to a 12 volt battery can be used to power an S8 CPAP and this humidifier.
This humidifier integrates with the full line of ResMed S8 and S8II Series CPAP/APAP/VPAP Machines. The H4i Heated Humidifier is not compatible with:
- AutoSet CS 2
- S7 AutoSet Spirit
- S7 Series
- VPAP III Series
- VPAP Malibu
VPAP III Series is not an S8 model and will only work with the HumidAire 2i Heated Humidifier.
The S8 AutoSet II and Elite II are compatible with this product, but the CPAP machines were manufactured BEFORE the H4i was manufactured. When setting either machine, please note that H3i will appear on the display.
Maximum Fill Level Tips
- Do not fill the water tank above the maximum fill line. Damage to the humidifier or therapy device may occur. If the water tank is overfilled, water may leak out of the tank inlet (located on the back of the tank) when installing the tank lid.
- When disconnecting the hose from the tank outlet, be careful to ensure that the hose is not holding water. Water could travel through the hose and into the machine.
- Use only room temperature distilled water in the tank. Do not put any chemicals or additives into the water. Possible airway irritation or damage to the water tank may result.
- Remove the tank, empty all water, and replace the empty tank before transporting the humidifier base.
- Do not attempt to fill the water tank while it is inside the humidifier.
- To avoid spilling, do not disconnect the humidifier from the therapy device with water in the tank. Remove the water tank from the humidifier before disconnecting the therapy device.
- Do not turn the humidifier on without the water tank installed. The Humidifier number setting must remain on 0 if there is no water in the water tank.
- The humidifier door must be set in the open position before removing the water tank. Do not remove the water tank without making sure that the humidifier door locks into the open position.
- Do not move the humidifier while the water tank has water in it.
Manufacturer Warranty
This product comes with a 1 Year Manufacturer Warranty. CPAP.com will work with the manufacturer on your behalf if the product needs repairs. Please follow these steps:
- Contact us at cpap@cpap.com or 1-800-356-5221 to receive an RMA (Return Merchandise Authorization) Number before returning the equipment
- Include a note with the product describing the issue you are experiencing, along with your full contact information to include a return shipping address and the RMA number provided to you
- Ship only the defective items to CPAP.com at 10101 Stafford Centre Drive, Stafford, TX 77477
- Do not return accessory items such as the carry bag, hose or power cords
- Loaner Humidifiers are available for rental during the warranty process
- Email updates will be sent to keep you informed as the product moves through the warranty process
- CPAP.com will contact the manufacturer on your behalf and handle all shipping between us and the manufacturer
- The repaired or replaced unit will be returned to you. Shipping charges may apply.
Please note: The manufacturer warranty is voided by water damage or misuse of the machine.
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 cpap@cpap.com
- 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.
Nasal congestion also leads to mouth breathing, which perpetuates the problem of dryness. If this is an issue for you, try a heated humidifier.
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
Stand Alone Humidifiers can be used with almost any machine as long as an integrated humidifier is not being used and the machine does NOT have a built in humidifier. The Fisher & Paykel HC150 Heated Humidifier With Hose, 2 Chambers and Stand is a stand alone heated humidifier that includes ambient tracking to keep the humidity consistent independent of room temperature.
- Integrated Humidifiers
Integrated Humidifiers connect directly to the machine the humidifier was made to be used with. This provides the convenience of being able to remove the humidifier from the machine for traveling or other purposes. Here are some of the integrated humidifiers we carry:
PR System One 60 Series Heated Tube Humidifier with Heated Tube
Transcend Heated Humidifier
XT Heated Humidifier
- Built In Humidifiers
Built In Humidifiers are permanently affixed to their machine and cannot be removed. The chamber can still be removed for cleaning, however the heating element is a part of the machine. The advantage of built in humidifiers is they generally take up less space than a machine with an integrated or stand alone humidifier. Here are some machines that have a built in humidifier:
AirSense™ 10 AutoSet CPAP Machine with HumidAir™ Heated Humidifier
ICON Auto CPAP Machine with Built-In Heated Humidifier and ThermoSmart Heated Hose
iCH Auto CPAP Machine with PVA and Built-In Heated Humidifier
+ See More
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.
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.

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
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.

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
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.

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.
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
- 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
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.

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.
- A7034 is Nasal Mask
- A7034 is Nasal Pillow Mask
- A7030 is Full Face Mask
- A7027 is Hybrid Mask
- A7044 is Oral Interface Mask (Oracle)
- A7035 is Headgear for Mask - Any Style
- A7036 is Chinstrap - Any Style
- A7032 is Replacement Nasal Mask Cushion
- A7033 is Replacement Nasal pillows
- A7031 is Replacement Full Face Mask Cushion
- A7028 is Replacement Hybrid Mask Cushion
- A7029 is Replacement Hybrid Mask Nasal Pillow
- A7046 is Replacement Humidifier Chamber
- A7037 is Tubing / Hose - Long & Short Tubes
- A4604 is Heated Tubing
- A7038 is Disposable Filter (White / Paper)
- A7039 is Washable Filter (Gross Particle / Foam/ Black)
- E0601 NU is CPAP Purchase
- E0601 NU is APAP Purchase
- E0470 NU is BiPAP Purchase
- E0470 NU is BiPAP Auto Purchase
- E0471 NU is BiPAP ST Purchase
- E0471 NU is BiPAP Auto SV Purchase
- E0562 NU is Heated CPAP Humidifier
- E0561 NU is Passover or Cool CPAP Humidifier
- E0601 RR is CPAP Rental
- E0601 NU is APAP Rental
- E0470 RR is BiPAP Rental
- E0470 RR is BiPAP Auto Rental
- E0471 RR is BiPAP ST Rental
- E0471 RR is BiPAP Auto SV Rental
- E1356 is Oxygen Concentrator Battery
- E1357 is Oxygen Concentrator Battery Charger
- E1358 is Oxygen Concentrator DC Cable
- E1390 is Portable Oxygen Concentrator
E1399 is Miscellaneous and is used for other CPAP and Oxygen items.
HumidAire H4i Heated Humidifier
H4i Heated Humidifier Water Chamber
The whole process of ordering from CPAP.com was very smooth. Everything was also completed very quickly and I had my order in 3 days. Will order from them again when the need arises more...
Lots of condensation in the hose. Had to keep unit on the floor. Liked my dreamstation better.
The H4i replaced the H3i perfectly. My Resmed S8 elite didn't know the difference, but my nose did. Warm air with the perfect humidity made it happy all night long. more...
Easy to use, snaps right onto the front of the CPAP, with power and air passing through (no other connections). Compact. Reasonably easy to fill. I only use mine when I've got a cold, since I don't really need the humidification all the time and filling it is something of a hassle. But you'll love having this when you're sick, or if you like a humidifier every day. more...
1 person found this helpful.
Don't know why old one just stopped working but the new unit works just fine!

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