Short answer: yes, you can still breathe. A CPAP machine does not breathe for you; it holds your airway open with a gentle stream of air. When the power dies, the air stops, your airway goes back to doing what it did before you had CPAP, and you breathe room air through the mask's vent holes and, on a full-face mask, through a safety valve that opens automatically. You will not suffocate. What actually happens next is a little more nuanced than most articles admit, so this guide covers it honestly: what it feels like, why most people wake up (and why some do not), what the manuals say, whether skipping a night is dangerous, and what to buy if you want your machine to keep running when the grid does not.
What physically happens the moment your CPAP loses power
- The blower stops and the pressure in your mask drops to room pressure within a second or two.
- The small vent holes in every CPAP mask, which normally let your exhaled air escape, now also let fresh air in. On nasal masks and nasal pillows, you can also simply open your mouth.
- On a full-face mask, an anti-asphyxia valve (AAV) flips open. ResMed states that all of its full-face masks have one; Philips full-face masks have an equivalent "entrainment" valve. It is a flap held shut by air pressure; with no pressure, it falls open and connects the inside of the mask directly to room air.
- Your untreated sleep apnea comes back. A study of CPAP withdrawal found that obstructive events return on the very first night off therapy. That, not suffocation, is the real consequence of an outage.
When power returns, the ResMed AirSense 10 and AirSense 11 automatically restart therapy, according to the user guides. The Philips DreamStation returns to its home screen and waits for you to press start.
What it actually feels like, according to CPAP users
This is the part most articles skip. We read through years of threads on CPAP forums where people described the night the power went out, and their experiences cluster into a few patterns.
- Most people wake up, and it is usually the silence that does it. Several users say it was the fan noise stopping, not any trouble breathing, that woke them. Others describe the sensation of "no air getting through the mask" waking them within a minute or two.
- Breathing through a dead machine is possible but feels harder. A common description is that you can breathe through the mask, but there is more resistance, like breathing through a scarf. Many people take the mask off and go back to sleep without it.
- Some people sleep right through it. A handful of users report waking to find the machine had been off for 30 to 45 minutes, and one reported four to five hours on a full-face mask. Sleeping pills, alcohol, and sheer exhaustion make this more likely.
- A minority describe panic or a choking feeling. One user wrote that the first time it happened, they felt like they were choking and found it "pretty horrible." This is a response to the sudden change, not a sign that air is not available, but it is real, and it is the reason we recommend a backup below for anyone who has felt it.
- The morning after feels bad. Sore throat, snoring reported by a partner, a headache, and "feeling grotty all day" are the typical reports after a full night without therapy.
One experienced forum member summed up the consensus well: the concern in an outage is having severe apneas without treatment, not suffocation.
What the mask manuals say (and the fine print)
Manufacturer guidance is more cautious than user experience, and it is worth knowing why. ResMed's Mirage Quattro guide explains that the mask "incorporates vent holes and a built-in valve so that you can continue to breathe fresh air if the airflow to your mask is impeded for any reason." The same document tells you to test the valve regularly: block the swivel end of the mask with your hand and confirm you can still breathe freely. If the valve is stuck, damaged, or missing, do not use the mask.
At the same time, ResMed's AirFit F30i guide states that the mask should not be used unless the device is turned on, "to reduce risk of rebreathing exhaled air," and Philips' DreamStation manual warns that rebreathing for longer than several minutes can, in some circumstances, lead to suffocation. The way to read those two statements together: the valve is a fail-safe that keeps you breathing until you wake up and deal with the situation. It is not designed for you to deliberately sleep all night in a full-face mask with the machine off. If the power goes out, either restore power or take the mask off.
Does mask type matter when the power is off?
| Mask type | What happens with no power | What users report |
|---|---|---|
| Nasal pillows | Air through the pillows' vents and through your mouth. No valve needed. | Easiest to breathe with off. Congestion is the main complaint, since you may be forced to mouth-breathe. |
| Nasal mask | Air through the vent holes and through your mouth. | Similar to pillows. Some feel stuffy and remove the mask. |
| Full-face mask | Anti-asphyxia valve opens and vent holes admit room air. | Noticeably more resistance than the other two. Most people wake and remove it; a few sleep through. |
If you use a full-face mask, every current ResMed model in our range, including the AirFit F20 and AirFit F30i, has an AAV. Test it when you clean the mask: with the tube disconnected, put the mask on and breathe. If it is hard to breathe, the valve is stuck and the mask should be replaced.
Is one night without CPAP dangerous?
For most people with obstructive sleep apnea, a single night off is unpleasant, not dangerous. Sonoma County's emergency-preparedness guidance for CPAP users notes that regular users have "carry-over" benefits for a night or two and suggests sleeping on your side or semi-upright and avoiding alcohol and sedatives until power returns. Your untreated apnea will be back that night, so expect snoring and a rough morning.
The people who should treat an outage as a medical issue, not a nuisance, are those on BiPAP for a breathing or neuromuscular condition, those on supplemental oxygen bled into their CPAP, and anyone whose doctor has told them their apnea is severe enough that missed nights matter. If that is you, a battery backup is not optional, and it is worth asking your utility about medical baseline or priority-restoration programs, which many U.S. utilities offer to customers who depend on powered medical equipment.
More on the long-term picture: the impact of untreated sleep apnea on life expectancy and the best sleep position for sleep apnea.
What to do tonight if the power goes out and you have no backup
- Take the mask off if it feels uncomfortable. You do not need to keep it on.
- Sleep on your side, or propped up on two pillows. Back sleeping makes obstructive apnea worse.
- Skip alcohol and sleeping pills; both relax the airway and blunt your wake-up reflex.
- If you use a ResMed machine, leave it plugged in and the mask nearby. It will restart on its own when power returns, and you can put the mask back on.
- If you use a Philips machine, it will not auto-restart. Press start when you wake to find the power back.
- Do not run a generator indoors or in an attached garage to power the machine. Carbon monoxide is a far greater danger than a night without CPAP.
How much power does a CPAP actually use? (Less than you think)
This matters because it decides how big a battery you need. ResMed rates the AirSense 11 at a typical 56 W and the AirSense 10 at about 53 W, but those figures include the heated humidifier and are worst-case ratings. Real-world measurements published by users with power meters tell a different story:
| Setup | Typical draw (user measurements) | Energy per 8-hour night |
|---|---|---|
| CPAP only, humidifier and heated tube off | Roughly 5 to 20 W depending on pressure and leak | About 100 to 150 Wh |
| CPAP with humidifier on | Roughly 15 to 40 W | About 200 to 350 Wh |
| CPAP with humidifier and heated tube | Roughly 40 to 70 W | About 300 to 500 Wh or more |
The lesson every experienced battery user repeats: turn off the humidifier and heated tube when on battery. ResMed's AirSense 10 guide says the same thing. One CPAPtalk user put it plainly: heat and humidity are the biggest draw, and cutting them "will double or triple the hours you get." Going through a 120 V inverter instead of a direct DC cable roughly doubles the draw again, according to an RV electrical engineer who tested it.
Backup power options compared
There are four ways to keep a CPAP running without the grid. We sell one of them, and we will say plainly where each fits.
1. A CPAP battery with a built-in AC outlet (simplest)
These are lithium packs sized for a CPAP, with a standard wall outlet on the side. You plug in your machine's own power supply, which means no special DC cable and no compatibility question. The Zopec Explore 4000 is the one we stock: about two pounds, a built-in 110 V outlet, and 12 to 16 hours of runtime with the humidifier and heated tube off, depending on your pressure. It works with the AirSense 10 and 11, AirCurve, DreamStation, and most other machines. The smaller Zopec Explore Mini trades runtime for size and is the travel choice.
Why we like the built-in-outlet design for the AirSense 11 specifically: the AirSense 11's power connector carries a signal line, and users report ResMed told them the AirMini DC converter is not compatible with it. Plugging the original 65 W supply into an AC outlet sidesteps the whole issue. Keep a spare AirSense 11 power supply with the battery so you are not unplugging cables at 3 a.m.
2. A portable power station (most versatile)
EcoFlow, Jackery, Bluetti and similar units power everything from phones to a fridge and are the favorite of CPAP users who also want emergency power for the house. Real setups reported on CPAP forums:
- An EcoFlow Delta 2 (about 1 kWh) kept permanently between the wall and the CPAP. The station passes grid power through and switches to battery in under 30 milliseconds when the grid drops, so the machine never stops. This is the closest thing to a true uninterruptible setup.
- An EcoFlow River 2 Pro (768 Wh) running an AirSense 11 from its 12 V port through a DC converter, humidifier off, at 9 cm H2O: multiple nights per charge.
Two cautions. First, cheap "modified sine wave" inverters can make some power supplies buzz or overheat; choose a station with a pure sine wave AC output (nearly all name-brand units are). Second, several users advise not running the CPAP from a battery while that battery is charging unless the manufacturer specifically supports pass-through use.
3. A computer UPS (cheapest, shortest)
A basic uninterruptible power supply from an office store will run a CPAP without humidifier for an hour or two and switches over instantly, so you will not wake up. Several forum users with frequent short outages use exactly this. Look for a pure sine wave model and the highest watt-hour rating you can afford; the small 350 to 600 VA units common under desks give very little runtime.
4. Car battery or DC adapter (travel and emergencies)
The ResMed Air11 DC/DC converter runs the AirSense 11 from a vehicle's 12 V or 24 V outlet. It is the right tool for camping or a road trip and a fine emergency fallback (a car battery will run a CPAP without humidifier for several nights), but for a home outage it means sleeping in the car. If you travel in an RV, read how to use a CPAP machine in an RV.
What about a generator?
A gas generator will run a CPAP, humidifier included, but it needs to be outdoors and 20 feet from windows, and it is noisy. Plug the CPAP into a UPS or power station and plug that into the generator to smooth the power. Never run one indoors.
Sizing a battery: a simple rule
Take the watt-hour rating of the battery, multiply by 0.8 for real-world losses, and divide by your machine's draw. Examples with the humidifier off:
- A 100 Wh battery (the airline carry-on limit without approval) at 10 W: about 8 hours, one night.
- A 250 Wh battery at 10 W: about 20 hours, two to three nights.
- A 1,000 Wh power station at 10 W: most of a week.
Turn the humidifier on and divide those numbers by three or four. If you cannot sleep without humidification, size up accordingly or accept dry air for the duration of an outage.
Flying with a CPAP battery
The FAA limits lithium-ion batteries in carry-on baggage to 100 Wh each without airline approval; batteries of 101 to 160 Wh need airline approval and are limited to two spares; anything over 160 Wh is not allowed on passenger aircraft. Spare batteries must be in carry-on, never checked, with the terminals protected. Most purpose-built CPAP batteries are designed to sit just under 100 Wh for exactly this reason; most portable power stations are well over it and cannot fly. Our full guide: traveling and flying with your CPAP machine.
Will insurance pay for a backup battery?
Usually not. ResMed's own guidance is that most insurers consider a battery a convenience item. Many people use HSA or FSA funds instead; see using FSA/HSA for CPAP equipment.
A 10-minute outage plan for CPAP users
- Test your mask's valve (full-face users) the next time you clean it.
- Decide your tier. Rare, short outages: a UPS. Storm season or an unreliable grid: a CPAP battery or power station. Medical dependence: a power station kept in pass-through, plus a CPAP battery as a second layer.
- Learn the humidifier-off setting on your machine now, not by phone flashlight at midnight. On the AirSense 11 it is My Options > Humidity Level > Off.
- Keep a standard, unheated tube in the drawer. Heated tubes waste battery, and a spare costs little (ResMed standard tubing).
- Charge the battery monthly and before any forecast storm. Lithium packs lose charge slowly in storage.
- Register with your utility's medical program if you depend on the machine.
- Tell the people you live with that you are fine without it for a night, and where the battery is if you are not.
Frequently asked questions
Can you suffocate with a CPAP mask on if the machine stops?
No. Vent holes in every mask and the anti-asphyxia valve in full-face masks let room air in. Manufacturers do warn against deliberately wearing a full-face mask with the machine off for long periods because of the possibility of rebreathing some exhaled air, so the right response to an outage is to restore power or remove the mask, not to sleep on with a dead machine.
Will I wake up if my CPAP turns off?
Most users say yes, usually within a minute or two, and often because the fan noise stops. People who have taken sleep aids or alcohol, or who are extremely tired, sometimes sleep through it. If that worries you, a UPS or a power station in pass-through mode keeps the machine running without a gap.
Does the AirSense 11 restart by itself after a power outage?
Yes. ResMed's user guide says the AirSense 10 and 11 automatically restart therapy when power is restored. Philips DreamStation machines return to the home screen and need you to press start.
How long will a battery run my CPAP?
With the humidifier and heated tube off, a purpose-built CPAP battery such as the Zopec Explore 4000 is rated for 12 to 16 hours; with humidification on, expect a third of that. A 1 kWh power station will run a dry CPAP for most of a week.
Can I run my CPAP on a portable power station like a Jackery or EcoFlow?
Yes, through the AC outlet with your normal power supply, or through the 12 V port with the correct DC converter. Choose a pure sine wave unit and turn off the humidifier to extend runtime.
Is it OK to skip CPAP for one night?
For most people with obstructive sleep apnea it is unpleasant but not dangerous; your apnea returns that night and you will feel it the next day. People on BiPAP for respiratory conditions or on oxygen should treat any outage as urgent and have backup power.
The bottom line
An outage will not hurt you, but it will hand you a night of untreated apnea, and for some people a frightening few seconds. A backup is cheap insurance against both. If you want the simplest setup that works with any machine, the Zopec Explore 4000 plugs in like a wall outlet and covers a full night or two. Browse all CPAP batteries and power supplies, and if you are not sure what fits your machine, ask us.