The short answer: a CPAP draws 30 to 60W and uses 300 to 500Wh a night with the heated humidifier off, so the Jackery HomePower 3000 and its 3,072Wh battery runs one for six to ten nights. The HomePower 3600 Plus runs one for seven to eleven nights, and the Solar Generator 5000 Plus for ten to sixteen nights.
Turn the heated humidifier on and roughly halve every one of those. The HomePower 3000 is our pick, because it runs at about 30 decibels with zero exhaust and belongs in a bedroom. Here is the arithmetic.
The numbers behind the answer
A CPAP is a small blower, a fan pushing air at a set pressure through a hose. It is one of the gentlest loads in the whole backup-power catalogue: 30 to 60W while running, which is less than a lamp.
Over a seven or eight hour night that comes to 300 to 500Wh. Where you land in that range depends on your pressure setting, whether you use a heated hose, and how much of the night you actually wear the mask.
Divide the capacity of a unit by that nightly figure and you have your answer.
- 3,072Wh divided by 400Wh a night is about eight nights, call it six to ten across the range.
- 3,584Wh divided by 400Wh a night is about nine nights, call it seven to eleven.
- 5,040Wh divided by 400Wh a night is about twelve nights, call it ten to sixteen.
Nights per charge
Every figure is on the battery alone, no solar, with the CPAP counted at 400Wh a night without the humidifier and 800Wh with it.
| Setup | Energy per night | HomePower 3000 (3,072Wh) | HomePower 3600 Plus (3,584Wh) | 5000 Plus (5,040Wh) |
|---|---|---|---|---|
| CPAP, humidifier off | 300 to 500Wh | 6 to 10 nights | 7 to 11 nights | 10 to 16 nights |
| CPAP, heated humidifier on | 600 to 1,000Wh | 3 to 5 nights | 4 to 6 nights | 5 to 8 nights |
| CPAP plus a fridge | ~1,600Wh a day | About 2 days | About 2.2 days | About 3 days |
| CPAP, fridge, Wi-Fi, lights, phones | ~2,500Wh a day | About 1.2 days | About 1.4 days | About 2 days |
The two larger units expand, and that changes the last two rows completely. The HomePower 3600 Plus grows to 21kWh, which is more than a month of CPAP alone or eight days of the full essentials list. The 5000 Plus grows to 60kWh.
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The humidifier is the whole variable
Nothing else you can change about a CPAP moves the number this much. The blower is a fan, and fans are cheap to run. A heated humidifier warms water, and heating anything is expensive.
Switching the heated humidifier on roughly doubles the overnight draw, from 300 to 500Wh up to 600 to 1,000Wh. That takes the HomePower 3000 from eight nights to four. A heated hose adds to it as well.
For a one or two night outage, leave it on and do not think about it. For an outage that might run longer, turning the humidifier off is the single cheapest way to double your runtime, and it costs nothing. Some people find dry air uncomfortable rather than unusable, and a nose spray or a room humidifier that is not on the battery covers the gap. Speak to whoever manages your therapy if you are unsure, because comfort settings are a clinical question rather than an electrical one.
Running from the machine’s DC input
Many CPAP machines have a DC input, and where yours does, using it saves energy.
A mains adapter converts wall power into the low-voltage DC the machine actually wants, and it loses a slice of the energy as heat doing it. Feeding the machine DC directly skips that conversion, so the same night of therapy costs fewer watt-hours out of the battery. On a machine that already sips power the saving is modest in absolute terms, and across a week of nights it is real.
Two cautions. Not every machine has a DC input, and not every machine is meant to be run from one in the way you are imagining. Check the manufacturer’s guidance for your exact model rather than assuming, and use the cable or converter the manufacturer specifies. A CPAP is a medical device and it is not the place to improvise a power supply.
This is a medical load, so size it with margin
Most of what a backup battery runs is a convenience. If the Wi-Fi is off for a day, the day is worse. A CPAP is not in that category, and it deserves to be sized differently.
Three consequences follow.
Buy more capacity than the arithmetic demands. If your outages run two nights, do not buy two nights of battery. Buy a unit that gives you five or six, so that a longer outage, a colder night, or a day with no sun does not become a problem you have to solve at bedtime.
Do not let the CPAP compete with everything else. The mistake we see is a household running a space heater or a kettle off the same battery and finding it flat at 11 p.m. Decide in advance that the CPAP’s share is untouchable and budget the rest around it.
Charge before the storm, not during it. Top the unit to full when the forecast turns, so night one starts at 100 percent rather than wherever the unit happened to be sitting.
Travel and camping
The same numbers apply away from home, and there the noise and exhaust question becomes decisive. A battery unit runs at about 30 decibels with zero exhaust, so it sits inside a tent, a camper, or a hotel room with the door shut and does not wake anyone. A gas generator cannot go anywhere near a sleeping space, which makes it useless for this job whatever its output.
For a long weekend, a full charge is four nights of CPAP with the humidifier off and no sun at all. Set the panels out during the day and the trip stops having a limit, because a bright day returns more than a night costs.
What else you can run alongside
A CPAP uses so little that the interesting question is what shares the unit with it. On a HomePower 3000 with a CPAP already accounted for, you still have about 2,600Wh a day of room, which covers:
- A fridge, at 1,000 to 1,500Wh a day, because the compressor cycles rather than running continuously.
- Wi-Fi, at about 10W, which is roughly 240Wh a day and keeps you informed.
- Ten LED bulbs, at about 50W, which is 300Wh for a long evening.
- Phones and a laptop, at 150 to 300Wh a day.
That full list comes to about 2,500Wh a day including the CPAP, which is a little over a day on the HomePower 3000 and about two days on the 5000 Plus. Our home backup buying guide works through the same list against every unit we recommend.
Solar recharge over a multi-day outage
This is where a CPAP is a genuinely easy load to keep going for as long as an outage lasts.
A bright summer day returns 1,500 to 2,000Wh, which is three to five nights of CPAP with the humidifier off. In good weather the machine is effectively running on sunshine and the battery is only smoothing the gap between days. Hurricane-season outages, which are usually followed by clear hot weather, are close to the best case for this. The Florida hurricane backup guide sizes exactly that scenario.
A grey winter day returns a few hundred watt-hours, which is roughly one night of CPAP. That is still enough to keep the machine going indefinitely if it is all you are running, and nowhere near enough to also carry a fridge and a furnace. Plan winter on the battery and count the sun as a bonus.
The honest note about size
If a CPAP is genuinely the only thing you need to keep running, you do not need a 3,000Wh unit. A small power station covers several nights and costs a fraction of the price, and anyone telling you otherwise is selling.
The reason we still recommend the HomePower 3000 is that almost nobody wants only the CPAP. They want the CPAP and the fridge, and the phones, and enough light to get around, and the router so they can see when the power is coming back. The moment that list exists, the small unit is out of its depth on night two and the 3,000Wh-class unit is the right buy. Work through how to size a solar generator for home backup with your own list before you decide.
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Keep reading: Best solar generators for home backup · How to size a solar generator for home backup · Solar generator vs gas generator · Florida hurricane backup guide