CPAP in Winter: Rainout, Cold Air and a Dry Nose
CPAP in Winter: Rainout, Cold Air and a Dry Nose
British winters are hard on CPAP. Cold bedrooms turn your humidifier against you, central heating dries your nose, and every cold that goes round the office threatens a night's therapy. Here are the seven problems winter brings — why each happens, what to try first, and what fixes it for good.
Jump to your problem.
Why your CPAP behaves differently when it's cold.
If your therapy felt fine all summer and started going wrong in October, you're not imagining it. Almost every winter CPAP complaint comes back to one simple fact: warm air holds more moisture than cold air.
Your humidifier warms the air and adds water to it, so that what reaches your nose is comfortable rather than dry. In summer, the hose between the machine and your mask sits in a room that's roughly as warm as the air inside it, and nothing much happens on the way. In a cold British bedroom in January, that same hose is a cold pipe. The warm, moist air cools as it travels along it — and when moist air cools, the water comes out of it. That's condensation, and in a CPAP hose it's called rainout.
Turn the humidifier down to stop the rainout and you hit the opposite problem. Cold winter air is already dry, central heating dries it further, and now your nose is getting less moisture than it needs. That's why so many people end up stuck — too wet, then too dry, then too wet again — because the two problems have the same cause and opposite-looking fixes.
Add the colds and flu that circulate every winter, and dry, chapped skin under the mask, and you have the full set of winter CPAP problems. The good news is that every one of them is well understood and fixable, and most can be improved tonight with a setting change before you buy anything at all.
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Find your problem in ten seconds.
Match what you're experiencing to the problem behind it, then jump to the fix.
| What you're noticing | The problem | Go to |
|---|---|---|
| Gurgling in the hose, drips, a wet face or mask | Rainout | Problem 1 |
| Air feels cold and wakes you; you pull the duvet over the hose | Cold air delivery | Problem 2 |
| Dry, crusty, sore or bleeding nose in the morning | Air too dry | Problem 3 |
| Blocked nose from a cold, can't breathe through your nasal mask | Seasonal congestion | Problem 4 |
| Red, chapped or flaky skin where the mask and straps sit | Winter skin | Problem 5 |
| Water left in the hose in the morning; dark spots inside | Damp hose | Problem 6 |
| More leaks than usual, mask shifting when you curl up | Winter leaks | Problem 7 |
Water gurgling in your hose.
You wake to a gurgle, a splash of water on your cheek, or a mask that's wet inside. It's the single most common winter CPAP complaint, and it wakes people up far more than they expect.
Precautions: try these first, tonight
Put the machine below your mattress height. This is the cheapest fix of all. If the machine sits lower than your head, any water that forms runs back towards the humidifier instead of down the hose into your mask.
Turn the humidity down one step. Just one, for three or four nights. Less moisture going in means less to condense. If your nose then goes dry, you've found the balance point and need a heated tube — see below.
Use Climate Control Auto if your machine has it. ResMed AirSense 10 and AirSense 11 machines have an automatic mode that manages humidity and tube temperature together to prevent rainout, when used with a compatible heated tube. If you have a heated tube and you're on manual settings, switching to auto is often all it takes.
Route the hose under the duvet. Running the tube under the covers keeps it near body temperature for the last stretch before the mask, which is where rainout tends to collect.
Take the chill off the bedroom. You don't need a warm bedroom, just a less cold one. Even a small rise in room temperature shrinks the gap between the air in the hose and the air around it.
Never warm the hose on a radiator, with a hot water bottle or an electric blanket. Uneven, uncontrolled heat can damage tubing and isn't a safe way to solve this. Use a product designed for it.
A heated tube is the proper fix. A thin heating wire runs along the length of the hose and keeps it warm from machine to mask, so the air never cools enough to drop its water. It also lets you keep the humidity high enough for a comfortable nose, which solves Problem 3 at the same time. Heated tubes are made for specific machines — match the listing to your model.
Heated tube or hose cover? A fleece hose cover insulates the tube and slows the cooling, which is enough for mild rainout in a moderately cold room. In a genuinely cold bedroom, or if you like your humidity high, it won't be enough on its own — a heated tube is the reliable answer. If you use a heated tube and want to add a cover too, check the tube's own instructions about covering it first.
Cold air blasting your face.
The air from the mask feels chilly, your nose goes numb, and you find yourself burrowing under the duvet with the hose — which then pulls the mask out of place.
What you're suffering
Breathing cold air all night is uncomfortable in a way that's hard to describe until you've had it: a cold nose, a cold throat, and a sense of chill that makes it hard to settle. Some people find it triggers sneezing or a runny nose. Many simply wake more often, and take the mask off to get warm.
Why it happens
Your machine draws in air from the room. If the room is cold, so is the air — and a long, uninsulated hose gives it plenty of time to cool further on the way to you. Without a humidifier, or with the humidifier turned low to avoid rainout, there's nothing warming it at all.
Precautions: try these first
Keep the machine away from cold spots. Not on a windowsill, not by an outside wall, not on the floor where cold air settles. Somewhere stable, below mattress height, with the air inlet clear.
Use your humidifier. If you've switched it off, turn it back on at a low setting. Warm, moist air is far more comfortable than cold, dry air, and you can manage rainout separately.
Tuck the hose under the duvet for the final stretch — but secure it so it doesn't drag on the mask when you turn over.
Don't cover the machine to keep it warm. It needs free air around it. Blocking the inlet or the case can make it overheat and stop it working properly.
The same heated tubes that cure rainout keep the air warm all the way to your face. If your machine has no humidifier, adding one is the bigger change — it warms and moistens the air before it ever reaches the tube.
A dry, sore or bleeding nose.
You wake with a nose that feels raw and crusty, sometimes with a little blood. It's worse in winter and worse in centrally heated homes — and it's usually a humidity problem.
Precautions: try these first
Turn your humidity up one step for three or four nights. If rainout appears, that's the sign you need a heated tube to hold higher humidity without water in the hose.
Check the water chamber isn't empty by morning. In winter, with the heating on, a chamber can run dry before you wake — and the last hours of the night are then delivered completely dry. Fill it to the line before bed.
Use distilled water. Much of the south and east of England has hard water, which leaves limescale in the chamber and makes it work less efficiently.
Try a saline nasal spray before bed. It's cheap, available from any pharmacy and soothes a dry nose directly.
See your GP for frequent or heavy nosebleeds, or ones that won't stop. Light spotting from dryness is common; anything more needs proper assessment, not equipment changes.
The winning combination is a humidifier plus a heated tube: the humidifier adds the moisture, and the heated tube lets you run it high enough without rainout. If you're using a machine without a humidifier at all, that's the first thing to change.
A cold, a blocked nose, and a nasal mask that won't work.
Every winter, a cold goes round. If you use a nasal mask or nasal pillows, a blocked nose can make therapy feel impossible — and a lot of people simply stop for the week.
What you're suffering
You put the mask on, and your nose is too blocked to breathe through it. Your mouth falls open, the air rushes straight out, the machine roars, and you take it off. For one night that's frustrating; for a week of a heavy cold it means a week of untreated apnoea — and the tiredness that comes with it, on top of feeling ill.
Why it happens
Nasal masks and pillows only work if you can breathe through your nose. When congestion blocks it, the pressurised air takes the easiest way out, which is your mouth. There's no seal for the machine to work against, so therapy stops working in any useful sense.
Precautions: try these first
Raise your humidity while you're congested — moist air is easier on an inflamed nose.
Use a saline rinse or spray before bed. A pharmacist can also advise on decongestants that are suitable for you and how long it's safe to use them.
Sleep with your head slightly raised on a wedge, which can help drainage.
Keep using CPAP if you possibly can. Even partial nights are better than none.
Speak to your GP or clinic if you have a high temperature, chest symptoms, or congestion lasting more than a couple of weeks.
The real fix: a backup full face mask
The single most useful thing a nasal-mask user can own in winter is a full face mask kept in the drawer for bad nights. It covers your nose and mouth, so you can breathe through either and the therapy keeps working. You use it for the week of the cold, then go back to your usual mask. Many people find they prefer it all winter.
All three connect to standard CPAP tubing. If you're new to full face masks, the fitting templates on each product page help you pick the right cushion size.
A safety note on magnets. Several full face masks, including the AirFit F20 and F40, use magnetic headgear clips. If you or anyone sharing your bed has a pacemaker, ICD, neurostimulator or other implanted medical device, check the mask's safety information and speak to your clinician before using a mask with magnets.
Sore, chapped skin under the mask.
Winter dries your skin out everywhere, and the places the mask and straps sit all night take the worst of it — the bridge of the nose, the cheeks, and the back of the head and neck.
What you're suffering
Red marks that don't fade by lunchtime. Flaky, tight skin across the nose. A sore spot where the straps rub on your cheeks or neck. In winter, skin that would cope in summer starts to break down, and a mask that was comfortable in August becomes something you dread putting on.
Why it happens
Cold air outside and central heating inside both strip moisture from your skin, so it's less resilient to pressure and friction. At the same time, people often tighten their mask in winter to stop the leaks caused by rainout or a worn cushion — and extra tension on dry skin is exactly what causes soreness.
Precautions: try these first
Loosen the straps. This is the most important one. Tighten only until the leak stops, lying down, in your sleeping position. Over-tightening causes more skin problems than anything else.
Wash your face before bed, and moisturise in the morning, not at night. Night-time creams transfer onto the cushion, make the silicone slippery and break it down faster — which leads to leaks, and more tightening.
Keep the cushion clean. Wash a silicone cushion daily in warm water with mild, unscented soap and rinse it thoroughly; soap residue irritates skin. If you use a memory foam cushion, never wash it — wipe it only.
See your GP or clinic if skin breaks or blisters. That's beyond a comfort issue, and it may mean the mask or size isn't right for you.
Soft covers stop the straps rubbing, and a memory foam cushion moulds to your face rather than pressing into it — the usual answer for people whose skin doesn't tolerate silicone.
A damp hose, and the start of mould.
Winter rainout doesn't just wake you up. The water it leaves in the hose sits there all day — and a warm, damp, dark tube is exactly where mould gets started.
What you're suffering
Water still sitting in the hose in the morning. A musty smell when you put the mask on. Eventually, black or pink spotting inside the tube. It's unpleasant, and it's something people often only notice once it's well established.
Why it happens
Every night of rainout leaves water behind. If the hose is left coiled on the bedside table, the water pools in a low loop and doesn't dry. Over a few weeks, that damp film becomes a place for growth — and the hose is impossible to inspect properly from the outside.
Precautions: try these first
Empty the humidifier chamber every morning. Never leave water standing in it all day.
Hang the hose to dry with both ends pointing down — over a shower rail or a door — so the water drains out instead of pooling.
Wash the hose weekly in warm soapy water, letting it run through the whole length, then rinse and hang it.
Don't try to rescue a mouldy hose. You can't reliably clean the inside of a ribbed tube, and bleach damages it. Replace it. If you see growth inside the machine itself, stop using it and contact your provider.
Fix the rainout (Problem 1) so the water stops forming in the first place.
A long brush makes weekly cleaning far more thorough, and replacement tubing is inexpensive — standard tubing is due every three months anyway.
Our full cleaning guide covers every part of the system, including what never to use on CPAP equipment.
Leaks that get worse in winter.
More hissing, air in your eyes, leak figures creeping up in your app. Winter doesn't wear your mask out — but it exposes a mask that's already on its way out.
What you're suffering
Air escaping round the cushion, sometimes blowing into your eyes. A mask that shifts when you curl up or burrow into the pillow. Waking to adjust it, again and again, and tightening the straps a little more each time.
Why it happens
Winter changes how you sleep. People curl up, pull the covers higher and press their face further into the pillow, all of which push the mask off its seal. Night-time skin creams, used more in winter, make the cushion slippery. And a cushion that's two or three months old has already lost some of its shape — it was coping in summer, and the extra demands of winter are enough to tip it over.
Precautions: try these first
Refit the mask lying down, in the position you actually sleep in, with the machine running.
Loosen, then tighten only until the leak stops. Over-tightening distorts the cushion and creates new leaks.
Check your cushion's age. A silicone cushion is typically a one-to-three-month part. If yours is older and has gone soft, sticky or cloudy, that's your leak.
Check your headgear. Straps that have lost their stretch can't hold even a new cushion in place. Headgear typically lasts around six months.
Watch your app. A leak figure rising steadily over a few weeks is the clearest early sign of a worn cushion — our guide to reading your CPAP data explains what to look for.
Most winter leaks are fixed by replacing the cushion, and the rest by replacing the headgear — far cheaper than a new mask.
Which heated tube fits my machine?
The most important precaution before buying: heated tubes are made for specific machines and are not interchangeable. Check the model name on your machine first.
| Your machine | Heated tube to look for | Option |
|---|---|---|
| ResMed AirSense 10 | ResMed ClimateLineAir Heated Tube (AirSense 10) | Genuine ResMed |
| ResMed AirSense 10 or AirCurve 10 | ResLab Heated Replacement Tube | Compatible alternative |
| ResMed AirSense 11 | ResMed ClimateLineAir Heated Tube (AirSense 11) | Genuine ResMed |
| Any machine, without heating | Fleece Hose Cover over standard tubing | Insulation only |
A few points worth knowing before you order:
The AirSense 10 and AirSense 11 tubes are not the same. They connect differently, so a tube for one won't work properly on the other. If you've upgraded machine, you'll need a new heated tube too.
A heated tube needs a humidifier to be worthwhile. Its job is to stop humidified air condensing. Without humidification, it warms the air but doesn't address dryness.
Genuine or compatible is your choice. Both do the same job. Compatible tubes cost less; genuine tubes carry the original manufacturer's backing. Fitting a compatible part may affect any remaining manufacturer warranty on your system, so check if that matters to you.
Not sure which machine you have? The model name is printed on the machine and usually on the screen when it starts up. If you're still unsure, contact us before ordering.
Your winter CPAP set-up checklist.
Ten minutes now saves a lot of broken nights in January.
Five winter CPAP myths.
Quick answers on CPAP in winter.
How do I stop water in my CPAP hose?
Place the machine below mattress height so water drains back rather than towards the mask, turn the humidity down a step, and run the hose under the duvet. If your machine supports it, use Climate Control Auto with a heated tube. In a cold bedroom, a heated tube is the reliable long-term fix.
What is CPAP rainout?
Rainout is condensation inside your CPAP hose or mask. Warm, humidified air from the machine cools as it travels through a cold tube, and the moisture turns back into water. It causes gurgling, drips and a wet face, and it's most common in cold bedrooms in winter.
Do I need a heated tube for my CPAP?
Not everyone does, but it's the most effective fix for rainout and lets you keep humidity high enough for a comfortable nose in a cold room. If you get water in your hose or a dry nose every winter, a heated tube matched to your machine model is usually worth it.
Why does CPAP make my nose dry in winter?
Cold outdoor air holds little moisture and central heating dries indoor air further, so your machine pushes dry air through your nose all night. Turn your humidity up a step, make sure the water chamber doesn't run dry before morning, and try a saline spray. A heated tube lets you raise humidity without rainout.
Can I use CPAP with a cold or blocked nose?
Yes, and it's worth continuing if you can. A nasal mask struggles when your nose is blocked, so many people keep a full face mask as a backup for congested nights. Raising humidity and using a saline spray also help. See your GP if you have a high temperature or chest symptoms.
Does a CPAP hose cover help with condensation?
A fleece hose cover insulates the tube and slows cooling, which helps with mild condensation in a moderately cold room. It won't fully prevent rainout in a very cold bedroom, where a heated tube is more effective. If you use a heated tube, check its instructions before covering it.
Will an AirSense 10 heated tube fit an AirSense 11?
No. AirSense 10 and AirSense 11 heated tubes connect differently and are not interchangeable. If you've moved to an AirSense 11, you'll need a heated tube made for it. Check the model name on your machine before ordering.
More UK-specific CPAP guidance.
This guide is general information, not medical advice. Always follow the instructions supplied with your own machine, humidifier, tubing and mask, and your sleep clinic's guidance where it differs from anything here. Check that any heated tube or accessory is compatible with your specific machine model before use.
Never adjust your prescribed pressure settings yourself. See your GP or sleep clinic for frequent or heavy nosebleeds, broken or blistered skin, a high temperature or chest symptoms, or congestion that lasts more than a couple of weeks. If you find mould inside your machine, stop using it and contact your provider. Masks with magnetic clips may not be suitable if you or anyone sharing your bed has an implanted medical device — read the mask's safety information and speak to your clinician.
AirFit™, AirTouch™, AirSense™, AirCurve™, ClimateLineAir™, HumidAir™, InfinitySeal™, QuietAir™ and ResMed™ are trademarks of ResMed Ltd. ResLab products are compatible replacement parts and are not manufactured, endorsed by, or affiliated with ResMed Ltd; ResMed names are used only to identify compatibility.
