What Size Generator for CPAP Machine? (Startup vs. Running Watts)
Medical device demanding clean sine-wave power — only inverter generators qualify.
Wattage at a Glance
Danger Zone — THD Threshold
Conventional generators output 15–25% THD — dangerous for CPAP electronics
Quick Reference
- Running Watts
- 30–60W (without humidifier)
- With Humidifier
- Up to 150W
- Power Quality Needed
- Pure sine wave, <3% THD
- Generator Type Required
- Inverter generator only
- 8-Hour Energy Draw
- ~240–480 Wh
Why CPAP Machines Require Inverter Generators, Not Conventional Ones
A CPAP machine draws just 30–60W — almost nothing in wattage terms. But watt draw is not the issue: power quality is. CPAP machines contain sensitive microprocessors and motor-speed controllers that require clean, stable 60 Hz AC power with less than 3% Total Harmonic Distortion (THD).
Conventional generators produce what engineers call a 'modified sine wave' — a choppy approximation of AC power that can damage CPAP motors over time, cause erratic pressure delivery, and void the manufacturer's warranty. Your sleep therapy effectiveness may also be compromised.
Inverter generators — Honda EU2200i, Yamaha EF2000iSv2, WEN 56200i — produce a true pure sine wave with under 3% THD, making them safe for all CPAP machines including models with heated humidifiers.
Runtime planning: a standard CPAP at 60W running for 8 hours draws only 480 Wh. A Honda EU2200i at 0.95 gallons for 8.1 hours will easily cover a full night's sleep plus a refrigerator, phone charger, and LED lights with fuel to spare. For camping without a generator, consider a Goal Zero Yeti or EcoFlow portable power station paired with solar panels as a silent, emission-free alternative.
Recommended Generators for This Load
Prices and availability are accurate as of March 23, 2026 and are subject to change.
2,200W — massive overkill for CPAP
Honda EU2200i (2,200W Inverter)
$1,099 – $1,199
Pure sine wave power, 8+ hr runtime, whisper quiet at 48 dB — the gold standard for CPAP users.
Check Current Price on Amazon2,000W starting
WEN 56200i (2,000W Inverter)
$399 – $459
Budget-friendly pure sine wave inverter generator — handles CPAP plus phone, laptop, and lights.
Check Current Price on Amazon1,800W — battery powered
EcoFlow DELTA 2 (Portable Power Station)
$799 – $999
Silent, zero emissions, pure sine wave — ideal for indoor use or camping where generator noise is prohibited.
Check Current Price on AmazonAs an Amazon Associate, GeneratorPicker earns from qualifying purchases.
Frequently Asked Questions
Can I run my CPAP on a regular generator?
Technically it may run, but it's not safe long-term. Conventional generators produce dirty power that can damage CPAP electronics, cause inconsistent pressure, and void your warranty. Always use an inverter generator or a battery-based portable power station for CPAP machines.
How long will a Honda EU2200i power a CPAP machine?
A standard CPAP at 30–60W will run for well over 8 hours on a single tank. The EU2200i runs 8.1 hours at 25% load (about 550W), so a 60W CPAP alone uses only about 10% of its capacity — you have plenty of power left for other essentials throughout the night.
Do I need a special adapter for my CPAP on a generator?
Most CPAPs use a standard 3-prong 120V plug, the same as any home outlet. No adapter is needed for a generator with standard household outlets. If you're using a battery power station, check that the CPAP is compatible with its inverter output (most modern power stations produce pure sine wave).
Running multiple appliances at once?
Use our free wattage calculator to add up all your loads and find the exact generator size you need.
Calculate My Total Wattage