What is “rainout”?

CPAP rainout occurs when cold temperature meets warm air in your machine. If your room is cold, the warm air from your CPAP is cooled and turns into condensation. The water droplets are blown through your hose and causes your machine to splash water on your face. This can be very uncomfortable and may cause patients to wake up in the middle of the night.

 What to do? 

Here are some simple steps to avoid rainout: 

  • Use Heated tubing:
    • Rainout is caused by heated air cooling within your CPAP hose. Using a heated hose can help maintain the warm temperature of the air until it reaches your mask. 
  • Use a hose cover/insulator
    •  You can also use a hose wrap which helps insulate the tube’s temperature and keep the air warm. This is very helpful if you prefer to keep your room cold. 
  • Adjust your room temperature
    • Raising your room temperature at night can help reduce the difference between the room and your CPAP’s humidifier. 
  • Adjust your CPAP humidity level
    • Alternatively, you can change your CPAP humidity level to match close to your room temperature. 
  • Use automatic settings
    • Some CPAP machines are able to automatically adjust the temperature/humidity throughout the night. Ask your Respiratory Therapist about automatic adjustments.

Try these tips if you are experiencing rainout. You can also speak to your Respiratory Therapist for more information!