How many watt-hours does a CPAP use per night?

A CPAP without a heated humidifier typically draws 30–60W for 7–8 hours: roughly 300–550Wh per night after inverter losses. With the heated humidifier on, draw can double or worse — it's often the biggest power consumer in the setup. On the run-time table, that puts a 500Wh station at roughly half a night with humidification.

What size power station runs a CPAP all night?

A 300–500Wh station covers one night without the humidifier with margin. For two to three nights of autonomy — outages, camping — look at 1,000Wh.

Can I run my CPAP with the humidifier on battery?

Technically yes on most units, but it can double the draw and cut your nights in half. Turning off humidification and heated tubing is the single biggest run-time win. Check your device manual for battery-operation guidance.

Is a power station safe to use with a CPAP?

Yes — a CPAP is a modest AC load, well within any mid-size station's inverter. Use the station indoors as the manual instructs (dry, ventilated), and confirm your CPAP manufacturer's guidance for battery operation, especially for travel.

Published September 7, 2026 · Updated September 7, 2026

CPAP Battery Backup: How Many Watt-Hours a Night Actually Takes

Power outages don’t pause sleep apnea. Neither does the campsite. Yet most CPAP battery advice online is either a forum guess (“mine lasted all night, I think”) or a product page in disguise. Here’s the actual arithmetic — the same watt-hour formula our guides use — applied to the one device you can’t afford to get wrong.

Note on method: spec-based analysis. Wattage ranges are typical manufacturer-published CPAP draws; your machine’s label and manual are the authority. No bench measurements yet — measured nights will be marked when they exist.

The only number that matters: your machine’s watts

Find it on the power brick or in the manual — it’s printed, e.g., “Output: 24V ⎓ 2.7A” (multiply: 24 × 2.7 ≈ 65W max). Typical ranges:

Setting	Typical draw	What it costs per 8-h night (incl. ~15% inverter loss)
CPAP, no humidifier	30–60W	~280–550 Wh
+ Heated humidifier	+20–60W	roughly doubles the cost
+ Heated tube	+10–20W	adds ~90–180 Wh

Most CPAPs also have pressure-dependent draw — a machine at 14 cm H₂O costs more than one at 8. If your brick says 65W max, budget with 45–60W and sleep is comfortable; that’s the planning number the rest of this page uses.

Run-time table: nights per capacity

Calculated for a 45W CPAP, 8 hours/night, humidifier off, ~15% inverter loss (8 h × 45W × 1.15 ≈ 414Wh/night):

Station capacity	Usable AC (~85%)	Nights (no humidifier)	Nights (humidifier on, ~90W)
300Wh	~255Wh	0.6 — not a full night	0.3
500Wh	~425Wh	1 night + margin	~0.5
1,000Wh	~850Wh	~2 nights	~1
2,000Wh	~1,700Wh	~4 nights	~2

Check the second column against your own machine: a 60W machine with the humidifier on (~110–120W effective) eats ~1,000Wh a night — a 1,000Wh station no longer covers even one. The settings matter as much as the capacity.

The three settings that double your nights

In order of impact, and all three come straight from the device’s own menu — no hardware hacks:

Humidifier off. The single biggest win. Heated humidification is often the largest consumer in the whole setup. A 45W machine with humidifier off is a ~414Wh night; with it, 800+.
Heated tube off (or set low). Adds 10–20W continuous — that’s a whole extra hour of the base machine per night.
AutoRamp / flexible pressure comfort features off for battery nights if you tolerate it — they extend run time near pressure peaks. This is a comfort trade-off, not a safety requirement; your call.

Check your manufacturer’s manual for battery operation guidance before a planned trip — some machines have specific travel-mode or DC-conversion notes, and the manual wins over any web advice, including this page.

Picking the station: what the CPAP scenario adds to the checklist

Pure-sine-wave inverter. Medical devices want clean AC. Every reputable brand (Jackery, EcoFlow, Bluetti, Anker SOLIX) uses pure sine wave output, but if you’re eyeing a bargain brand, verify this explicitly in the manual.
Low-noise. A station whining at 60dB beside the bed defeats the purpose. Fanless or quiet-invert models exist; decibel ratings live in the spec sheet.
Upside capacity. If the station is also your camping or outage unit (it should be), run the full calculator with the CPAP plus your other devices — the CPAP night (414Wh) stacks on top of everything else.
Recharge path. For camping: solar works. For outages: wall recharge speed matters — you want the unit full again before the second night.

Scenario math: camping week vs. outage night

A week at a campground with solar top-up: 7 nights × 414Wh ≈ 2,900Wh total. A 1,000Wh station + a 200W panel realistically returning ~650Wh/sunny-day covers a 1.5-day recharge cycle comfortably.

A 24-hour outage: CPAP night (414) + fridge bridge is the classic combo — but remember the fridge owns ~1,160Wh/day by itself. A CPAP-only night fits easily in anything 500Wh+; CPAP plus fridge wants 2,000Wh. The full home-backup budget lives in the home-backup guide.

Bottom line

Budget ~414Wh per night for a typical machine (45W, humidifier off, 8 hours, inverter losses) — then verify against your own power brick and adjust. A 500Wh station is one comfortable night; 1,000Wh is two; the humidifier is the budget-killer. Size once with the calculator, and the same unit that guards your sleep doubles as the camping or outage station — no duplicate purchase needed.