Frequently Asked Humidifier Questions

• Who should use a humidifier? Who should use a heated humidifier?
• How much water should a humidifier use during a night?
• My humidifier sometimes runs out during the night and most other nights is 3/4 empty in the morning. What is going on here?
• I have a full face mask; will I need more water during the night?
• I can't use my humidifier during some nights because my hose fills up with water condensation. What can I do about it and why does this happen?
• I have heard that wrapping the continuous positive airway pressure (CPAP) hose with fabric will help with "rainout." Is this true?
• Can I put my CPAP on top of the humidifier? Or should it only go next to it?
• How often should I change the water in the chamber? I never seem to use it all in one night's time.
• Does heated humidification wear out my mask and hoses faster?
• What is the difference between cold passover and heated humidification? Is one better than another?
• If I run out of distilled water, is it ok to use tap water once in a while?
• Should I turn on my humidifier before I go to bed to make sure the water is warm first?
• I usually use my humidifier during only the winter months when the heat is on in our house and, therefore, the air is dryer. Am I shortchanging myself? Should I be using it all year round?
• What are the overall benefits of humidification?
• What are the benefits of using a warm air humidifier vs. cold? Nasal pillows vs. mask? Which is better choice when using humidification?
• Is humidification helpful for upper airway resistance syndrome (UARS)?

Who should use a humidifier? Who should use a heated humidifier?
Humidification is prescribed to those experiencing symptoms of nasal drying, irritation, congestion, and dry throat. These are common side effects of CPAP therapy, which can be successfully treated with humidification. When trying to decide between passover (non-heated) and heated humidification, you may want to first consider the severity of your symptoms. Generally, heated humidification provides more humidity and is indicated for people with symptoms that don't resolve with passover humidification, i.e. more severe symptoms. Several studies have shown that patients on treatment pressures above about 9 cm H2O are better on heated humidification.

How much water should a humidifier use during a night?
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.

My humidifier sometimes runs out during the night and most other nights is 3/4 empty in the morning. What is going on here?
If you mean "why does it vary from one night to the next?" my guess is that you may be mouth breathing or have mouth leak. If you mouth breathe, you let lots of air escape from your mouth. All the extra air that escapes uses up your water more quickly.

I have a full face mask; will I need more water during the night?
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.

I can't use my humidifier during some nights because my hose fills up with water condensation. What can I do about it and why does this happen?
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 vapor) 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. The goal is to keep the tube and its air warm.

I have heard that wrapping the CPAP hose with fabric will help with "rainout." Is this true?
Yes. Wrapping the hose helps to insulate your treatment air from the lower temperature of the room, reducing "rain out." Please ask us about our tube warmers.

Can I put my CPAP on top of the humidifier? Or should it only go next to it?
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.

How often should I change the water in the chamber? I never seem to use it all in one night's time.
The water should be changed for each use.

Does heated humidification wear out my mask and hoses faster?
No, the tubing supplied with CPAP machines can withstand far higher temperatures than the heat generated by the humidifier.

What is the difference between cold passover and heated humidification? Is one better than another?
A cold passover system passes the air from the CPAP over a room temperature body of water in order to pick up moisture. A heated system heats the water and is able to provide higher levels of humidity. If a passover system resolves your dryness symptoms, then that is all you really need.

If I run out of distilled water, is it ok to use tap water once in a while?
Yes. It is recommended that you boil the tap water before using it in your humidifier.

Should I turn on my humidifier before I go to bed to make sure the water is warm first?
If you find the air dry and irritating, then you may want to turn your humidifier on 20 minutes prior to going to bed.

I usually use my humidifier during only the winter months when the heat is on in our house and, therefore, the air is dryer. Am I shortchanging myself? Should I be using it all year round?
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 moisturized.

What are the overall benefits of humidification?
Up to 40% of CPAP 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 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.

What are the benefits of using a warm air humidifier vs. cold? Nasal pillows vs. mask? Which is better choice when using humidification?
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.

Is humidification helpful for upper airway resistance syndrome (UARS)?
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.

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