Are you experiencing difficulties with humidification condensation (also known as “rainout”)? Find the answers to the most frequently asked questions about humidifier rainout here.
Q. I can’t use my humidifier some nights because my hose fills up with water. Why does this happen, and what can I do about it?
A. This is condensation of the humidified air and is often known as “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 the temperature drops and the air becomes cooler (eg, overnight), it has less capacity to carry water, so water condenses and forms droplets.
There are several ways to deal with this situation:
- Use ClimateLine™ heated tubing to enable constant temperature and humidity control.
- Try turning your humidity level down.
- Raise the temperature of your bedroom at night to reduce the difference between the room temperature and the humidifier.
- Run the air tubing beneath your blankets to keep it warm. Alternatively, you can cover the tube with a ResMed tubing wrap or even a tube sock. The goal is to keep the tube (and the air traveling through it) warm.
Q. How do I know what setting to use with my CPAP humidifier?
A. The H5i has added intelligence to help deliver constant humidity to minimize rainout during standard humidification. H5i humidification delivery is controlled by three inputs (ambient humidity, H5i settings and device flow) and adjusts the output to maintain consistent water delivery. In general, you should start at a humidity level setting of 3 and adjust up or down by 0.5 to address any drying or rainout issues. When using ClimateLine™ heated tubing, we recommend using Auto mode, which defaults to a Climate Control setting of 80° F. From there, you can adjust up and down as necessary. If using ClimateLine heated tubing in Manual mode, start with a humidity level setting of 3 and a heated tube setting of 80°. Adjust the humidity level up and down by 0.5 to address any drying or rainout issues, and adjust the heated tube level up and down in one-degree increments to find the most comfortable temperature setting.
Q. How much water should my humidifier use overnight?
A. The amount of water required by your humidifier varies from one humidifier to the next, from one patient to the next, and with the temperature and humidity of the bedroom, as well as the settings of the humidifier itself.
Q. How often should I change the water in the humidifier tub? I never seem to use it all in one night.
A. The water should be changed daily, even if you don’t use it all in one night.
Q. My humidifier sometimes runs out of water during the night and most other nights is 3/4 empty by the morning. What’s going on here?
A. The H5i water delivery output depends on ambient room conditions (temperature and humidity levels), the H5i settings and therapy pressure delivered by the device. If the room conditions change from night to night (e.g., one night the heater is left on in the house, and the next night it’s turned off), this can account for differences in the water usage.
It may also be that you’re breathing through your mouth, or have mask leak. Mouth breathing allows air to escape from your mouth, which can decrease the efficiency of the humidifier.
If mouth leak is under control or you are using a full face mask, trying one or more of the options below may help:
Q. I usually use my humidifier only in the winter months when the heat is on and the air is dryer. Should I be using it all year round?
A. If you’re finding that you have nasal symptoms at other times of the year, then you should probably use your humidifier then, as well. The added humidification may reduce the occurrence of these symptoms.
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