What Size Power Station Do I Need for a CPAP Overnight?
If you use a CPAP, losing power isn’t just inconvenient. It can mean a rough night, poor sleep quality, and a next day that feels like you got hit by a truck. The good news is that it is one of the easiest essential devices to run on a portable power station, if you know what size power station you need for a CPAP.
Let's walk through the key things you need to know to make sure your CPAP will be there for you, no matter what happens with your electricity.
Fast answer: what size power station you need for a CPAP overnight
For most people, the battery size matters more than inverter size. CPAP machines are not typically surge-heavy, so nearly any quality power station can handle the watts (which typically varies from about 50-120W).
The question is how big of a battery you need to get through the night with confidence. This is calcuated in watt-hours. Your average watts multiplied by the number of hours gets you to watt-hours.
| CPAP setup (8-hour night) | Typical energy use | What to shop for (battery capacity) |
|---|---|---|
| CPAP with heat off ~50W average (no heated humidifier/tube) | ~350–500Wh | 500Wh+ for comfort margin |
| Humidifier heat on low/medium ~80W avg (tube heat off) | ~600–900Wh | 1,000Wh+ to avoid cutting it close |
| Humidifier heat + heated tube ~100W avg (moderate-to-high heat) | ~900–1,200Wh+ | 1,500Wh+ for reliable overnight use |
These are practical planning ranges, not promises for every machine. If you want precision, measure your exact setup for a night or two and size from your real number. If you want maximum reliability without babysitting settings, plan for the heat on range.
You can measure your CPAP's energy use by getting a watt meter. It's a small device that you place on the outlet you run the CPAP on. Run it for a few nights in varying conditions to see how much energy it takes per night.
If you’re shopping right now and want a clean, safe baseline that works for most CPAP users: a power station around 1,000Wh is a strong one-night pick for many people, and 1,500Wh+ is the more comfortable choice if you use heat features or want extra margin.
If you want to use the power station to run other critical devices, such as phones, routers, TVs, and even refrigerators, make sure to buy a larger unit.
Browse our power station collection here.
What changes CPAP power draw the most
CPAP energy use is mostly controlled by heat and airflow demand. Two people with the same model can get very different runtimes depending on settings and conditions. These are the biggest factors that change your real-world draw:
| Factor | How it affects power use | Practical takeaway |
|---|---|---|
| Heated humidifier | Often the single biggest energy driver | If you need longer runtime, lowering or disabling humidity is the fastest win |
| Heated tubing | Adds a steady heater load throughout the night | Tube heat can be the difference between one-night and two-night battery sizing |
| Pressure settings | Higher pressures generally increase blower work | If your prescribed pressures are high, plan more battery margin |
| Mask leaks | Leaks can cause the machine to push more air to maintain pressure | A good mask fit improves comfort and reduces wasted work |
| Room temperature | Colder rooms make heaters work harder | Cold nights can raise energy use if you rely on heated humidity/tube |
| AC vs DC operation | Running through AC adds conversion losses | Using DC (when supported) can noticeably extend runtime |
Best planning move: If you use heat features regularly, assume you’ll want them during an outage too. Size the battery for comfort first, then consider solar or faster charging if you want multi-night use.
How to estimate your CPAP’s real usage (without guessing)
If you want the most reliable answer, measure your CPAP for a few full nights with your normal settings by using a watt meter. CPAP power use is one of those things where the estimate can be close, but a quick measurement turns it into a sure thing.
Option A: Check the power brick (fast, but conservative)
Look at the label on your CPAP power supply. You’ll usually see either watts (W) or amps (A) and volts (V). If you see amps and volts, you can estimate watts with: Watts ≈ Volts × Amps.
This number is typically the maximum the power supply can deliver, not what your CPAP uses all night. It’s still useful for planning because it helps you avoid undersizing.
Option B: Measure it overnight (best)
Plug the CPAP into a watt meter and run it overnight with your normal humidity/tube settings. In the morning, record the total energy used in kWh or Wh. That number is your baseline for battery sizing.
You want to leave a good cushion on top of this reading because all electrical systems and batteries have inefficiencies. For example, if you need 800Wh, you should get a battery that's at least 1,000Wh.
Option C: Use your machine data if available (good backup)
Some machines or companion apps provide usage or power-related data that can help you estimate. It won’t be as clean as a watt meter reading, but it can still guide your battery target.
Inverter sizing for CPAP
Inverter sizing is usually simple for CPAP machines. Most CPAPs have relatively low steady power draw and don’t behave like motors that need a huge startup surge. That means you typically don’t need a massive inverter just to run the CPAP.
If possible, it's best to avoid using the inverter. The inverter consumes power to change the battery's DC power into AC power at the inverter. Use the DC connections (USB, DC5521, 12V car outlet, etc.) if possible.
| What you’re doing | What matters | Planning note |
|---|---|---|
| CPAP only | Battery capacity (Wh) more than inverter watts | Even smaller power stations typically have enough inverter power |
| CPAP + other loads (phone, lights, laptop) | Total watts at the same time | Pick extra inverter headroom so you’re not juggling what’s plugged in |
| CPAP + heating devices (space heater, heated blanket) | High continuous watts | These can overwhelm most portable power stations quickly |
If you want the simplest “buy once” approach, prioritize a comfortable battery size first, then make sure the inverter is enough for whatever else you plan to run at the same time.
Battery sizing: 1 night vs 2–3 nights
Battery capacity is what determines how long you can run your CPAP. The cleanest way to size it is to use your measured overnight Wh. If you don’t have that number, use the planning ranges from the summary and choose the scenario that matches your settings.
Remember that this is for the CPAP machine only. It is often worth considering a larger power station to keep other critical devices running (phones, routers, TVs, etc.).
One night (8 hours)
If you want a comfortable one-night solution that doesn’t feel tight, most CPAP users do well with:
| CPAP settings | Safer battery target | Why this is comfortable |
|---|---|---|
| Heat off | 500Wh+ | Room for normal losses and small extras like phone charging |
| Humidifier on, tube heat off | 1,000Wh+ | Enough headroom for colder rooms and higher humidity settings |
| Humidifier + heated tube | 1,500–2,000Wh+ | Avoids the common problem of running out early morning |
Two nights
For two nights, multiply your one-night energy target by 2 and add a little extra margin. Two-night planning tends to push many people toward a larger battery or a recharge plan.
Three nights
Three nights is where recharging becomes the smarter strategy for most setups. You can absolutely size a huge battery, but it’s often more practical to plan on charging daily. If you want a calmer, more reliable plan, think of multi-night CPAP backup as battery + recharging.
Make a smaller power station last longer (real-world tactics)
Use DC power when your CPAP supports it
Many power stations run AC by converting battery DC into AC, which adds losses. If your CPAP supports a DC cable setup, it can reduce wasted energy and extend runtime. This is one of the simplest ways to get more hours from the same battery.
Turn off heat first if you need more runtime
Heated humidifiers and heated tubing are comfort features, but they can dominate energy use. If you’re trying to stretch runtime, reducing humidity and turning off tube heat usually makes the biggest difference.
Reduce leak and pressure waste
A good mask fit can reduce unnecessary airflow demand. If your mask leaks, the machine can work harder to maintain pressure, which costs energy. Fixing comfort and fit can also improve runtime.
Plan a simple recharge strategy for multi-night use
For 2–3 nights, the most reliable plan is often to recharge daily. Here’s the quick tradeoff:
| Recharge method | Best for | Downside |
|---|---|---|
| Wall AC | Fastest when grid power is available | Doesn’t help in a true outage |
| Car charging | Backup top-ups while driving | Often slow unless you have a stronger DC setup |
| Solar | Quiet, fuel-free daily replenishment | Depends on sun and panel size |
If CPAP backup is your priority and you want multi-night independence, solar is usually the most comfortable long-term upgrade because it lets you recover energy every day. One 200W solar panel can provide about 1,000Wh of energy in one full day of sun.
Recommended next step
If you want a clean answer without overthinking it, start by deciding whether you plan to run heat features during an outage. That single decision usually determines whether you’re shopping in the smaller “one-night” range or the larger “comfort + margin” range. From there, use the quiz to estimate a safe target based on your setup and runtime.
Quick FAQ
Will a 300Wh power station run a CPAP?
Sometimes, but it’s often tight. If you run heat features, 300Wh usually won’t make it through a full night. If you run heat off and your CPAP is efficient, it may work for shorter nights or partial runtime. If you want a reliable overnight plan, most people do better stepping up in battery capacity.
Will a 500Wh power station run a CPAP overnight?
For many CPAP users with heat off, yes, especially if you’re careful about efficiency and avoid running other loads. If you use humidity or heated tubing, 500Wh can fall short depending on settings and room temperature.
Do I need a pure sine wave inverter for CPAP?
In practice, most quality portable power stations output clean AC and work well with medical devices. If you are using AC power, stick with reputable brands like PECRON and avoid questionable no-name inverters. If your CPAP supports DC operation, that can be even more efficient.
Can I run a CPAP and a refrigerator on the same power station?
Yes, but now you’re sizing for two different things: the fridge’s start-up surge and the combined energy use over time. This is a common scenario for home backup, and it’s where larger battery sizes and a daily recharging plan start to matter. If you want to plan that setup properly, use the quiz and select both devices in the same session.
What if I want two or three nights without recharging?
You can do it, but it usually requires a larger battery capacity than most people expect, especially if you want heat features. A smarter and often cheaper path is pairing a moderate battery with a daily recharge method (solar is the quiet favorite).
Conclusion
A CPAP is one of the most important devices to plan for, and it’s also one of the most realistic to run on a portable power station. The key is sizing for how you actually sleep: heat off vs heat on, one night vs multiple nights, and whether you want a recharge plan.
If you want the simplest reliable approach, prioritize a comfortable battery size, keep some margin for colder nights and real-world losses, and consider solar if you want multi-night confidence without stress.