The air hitting your nose or face feels chilly, almost like a small draft blowing on you all night, even though your bedroom itself doesn’t feel that cold. It can make it harder to fall asleep, and some people find it makes them want to pull the covers up over their nose just to escape the sensation, which then interferes with the mask seal. It’s especially common if you’ve just started therapy or if it’s colder outside than usual.

Why this happens

The air pulled into your CPAP machine is room temperature air, and if it isn’t heated on its way to you, it can feel noticeably cooler than your own breath, especially once you factor in the pressurized airflow moving faster than normal breathing. This is worse in a cold bedroom, worse in winter, and worse with unheated standard tubing, since the tube itself doesn’t add any warmth to the air passing through it. Even with a humidifier running, if the tube isn’t heated, the warm air from the humidifier can still lose heat on its way through a cold tube before it reaches you.

Steps to troubleshoot

1. Turn on heated tubing if your machine supports it, and adjust the temperature dial (most systems allow a range, often somewhere around 60 to 86°F) until the air feels comfortable rather than cold or overly warm
2. If you don’t have heated tubing, ask about adding it, since this is the most direct fix for cold air specifically, separate from humidity level
3. Increase your humidifier setting slightly, since warmer humidified air tends to feel less like a cold draft even before it reaches a heated tube
4. Warm your bedroom a few degrees, since a smaller gap between room temperature and your machine’s output makes the air feel less jarring
5. Use a tube cover or insulation wrap if heated tubing isn’t available to you, which helps retain some warmth as air travels to your mask
6. Keep your machine somewhere it isn’t drawing in cold air directly, away from a drafty window, vent, or fan

Who to talk to

Your respiratory therapist can help you dial in the right combination of humidity level and tube temperature for your setup and season. Your DME can supply heated tubing or a tube cover if you’re currently on standard, unheated tubing. Your sleep doctor doesn’t typically need to be involved for this specific issue unless the discomfort is significantly affecting your ability to use the mask consistently.

Evidence

Research measuring conditions inside the CPAP mask found that both absolute humidity and temperature dropped significantly in winter compared to summer under every setup tested, including with a heated humidifier alone. Adding heated tubing on top of heated humidification kept in-mask temperature meaningfully higher than humidification without a heated tube, and was more likely to maintain a stable, comfortable humidity level through winter conditions.¹ This supports what respiratory therapists generally recommend: humidification alone often isn’t enough to solve a cold-air sensation, heated tubing addresses the temperature side of the equation directly.

Reference

1. Nilius G, Domanski U, Schroeder M, Woehrle H, Graml A, Franke KJ. Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing. Nat Sci Sleep. 2018;10:135-142.