A CPAP machine typically draws 30–60 watts, rising to 60–90W with a heated humidifier and near 100W with heated tubing running.
Figuring out how much power a CPAP uses comes down to three numbers: the machine’s wattage while running, how many hours you sleep, and your local electricity rate. Most machines sit in a familiar range — roughly 30–60 watts for a basic unit, more when comfort features kick in — and an 8-hour night usually costs well under $5 a month for the typical user.
The wattage question matters most if you’re sizing a battery backup, planning a camping trip, or just eyeballing your electric bill. Here’s what the numbers actually look like.
Typical CPAP Wattage Draw
A CPAP’s draw depends heavily on settings and accessories. Published figures vary because pressure, mask leak, humidity level, and room temperature all shift the load. The ranges below reflect what most sources and user measurements report:
- Basic CPAP, no humidifier: 30–60 watts while running
- With heated humidifier active: 60–90 watts (the humidifier adds roughly 25–35W on its own)
- With heated tubing: 90–100 watts or higher, especially in cold rooms or at high heat settings
These are running figures, not the adapter’s maximum rating. A power supply rated at 90W or 104W doesn’t mean the machine uses that much constantly — it means the supply can handle peak load. Actual draw usually sits well below that ceiling.
Watts to Watt-Hours: Nightly Energy Use
The number that hits your bill is energy — watt-hours — not instantaneous wattage. The math is simple: Wh = Watts × Hours.
For an 8-hour night, here’s what common draw levels produce:
| Draw Level | Watts | 8-Hour Energy Use |
|---|---|---|
| CPAP only | 40W | 320 Wh |
| With humidifier | 60W | 480 Wh |
| Peak / heated tube | 100W | 800 Wh |
Real-world reports often show lower figures than these steady averages. Adding humidification typically jumps that to 200–280Wh or more, depending on heat and ambient temperature.
What Does a CPAP Cost to Run Per Night?
At typical U.S. electricity rates, the cost is modest. One widely cited estimate puts an 8-hour night at well under $5 per month for most users. Another pegs the cost at roughly $0.04–$0.13 per night, or about $15–$48 per year, depending on your rate and settings.
That’s a two-fold swing between typical and peak, which is exactly why measuring your own unit beats guessing.
Sizing a Battery Backup and Reducing Draw
If you’re powering a CPAP from a portable power station or battery, size conservatively. Multiply the machine’s wattage by the hours you need, then add about 20% to cover inverter and battery inefficiency.
To cut consumption, the single biggest lever is the humidifier. Turning it off or lowering the heat setting can drop total draw by 25–35W, and skipping heated tubing trims more. In cold rooms, expect higher draw — plan extra battery margin rather than assuming you’ll hit the low end of the range. If you’re shopping for a camping setup, our tested battery picks for CPAP camping cover reliable options sized for overnight use.
FAQs
How do I measure my CPAP’s actual power draw?
Use a plug-in watt meter between the machine and the wall outlet. Set your normal pressure, humidity, and tube settings, then read the display during operation. Published specs are useful baselines, but your real-world draw depends on settings, mask leak, and room temperature, so measuring gives the most accurate number for battery sizing or cost estimates.
Does a CPAP use power when turned off?
Yes, a small amount. Most CPAP machines draw a few watts in standby for the internal clock, settings memory, and wireless features. The draw is tiny — typically under 5W — but unplugging the machine when not in use eliminates it entirely if you’re tracking every watt.
Can a solar generator run a CPAP all night?
Yes, if the generator’s capacity covers your machine’s draw. Most mid-size solar generators handle that, but verify the inverter’s continuous output rating handles your machine’s peak draw, especially with a heated humidifier running.
References & Sources
- ResMed. “Battery Guide for AirCurve 10 and Other Devices.” Provides typical and peak power figures for ResMed devices.