Quick answer
For an overnight CPAP plan, many households should compare the 300–700Wh usable range first, then test the actual machine before storm season.
What changes the number
- Humidifier on/off
- Heated hose on/off
- Pressure setting and mask leaks
- Whether the battery uses AC inverter or a DC adapter
- How many nights you need without recharge
Simple scenario table
| Scenario | Planning load | 8-hour target |
|---|---|---|
| Efficient CPAP, humidifier off | 25W | ~270Wh |
| Common mixed setup | 45W | ~490Wh |
| Humidifier/heated hose heavy | 75W+ | ~810Wh+ |
Safety note
This is not medical advice. Test the setup while grid power is available, keep the manufacturer power requirements handy, and ask the equipment provider about approved battery or DC-adapter options.