How many watts does a sump pump use
While running, a sump pump draws 800 to 1,050 W, and its startup takes 1,300 to 2,150 W for one second. To run it, the smallest portable generator is 2,000 W.
Watts for running and starting
| Load | Running | Starting |
|---|---|---|
| Sump pump, 1/2 hp | 800 to 1,050 W | 1,300 to 2,150 W |
The source is the Champion wattage chart, 04-17-26. Your own sump pump's nameplate shows the exact figure, in watts or in amps. Convert amps by multiplying by 120 V. Use 240 V only when a load, such as a well pump, sits on a two-pole breaker.
The smallest generator able to start it
Its running load can't exceed 80% of its rating at 1,050 W, and starting needs 2,150 W. The smallest common portable option, 2,000 W, handles both jobs and still has power to spare. The same generator also has to carry the running watts of every other load.
Sump pump, 1/2 hp, plus other loads
| Sump pump, 1/2 hp plus | Running | Peak at a start | Smallest portable |
|---|---|---|---|
| lights, TV and the router | 1,620 W | 2,720 W | 3,000 W |
| a freezer and lights | 1,700 W | 2,800 W | 3,000 W |
| a microwave | 2,250 W | 3,350 W | 3,000 W |
| a 1 hp well pump | 3,050 W | 5,050 W | 5,000 W |
| a window AC, 10,000 BTU | 2,250 W | 3,450 W | 3,000 W |
Running watts add up, and the biggest motor start is the only one that lands on top. Starting output on a portable is about 25% higher than its running rating. Each load listed in the appliance wattage chart.