At night, sump pump power per cycle remains the same, but overnight energy can vary from near-zero to high depending on rainfall.
For full system planning, use the WattSizing Calculator.
Quick Answer
Expect 500 to 1,500 running watts with high startup inrush. Overnight kWh (for a 10-hour window) can range from minimal to over 2 kWh in wet conditions.
Night-Use Notes
If your system relies on batteries overnight, model a wet-night case, not just normal dry-night behavior.
Typical Overnight Ranges
| Pump Size | Running Watts | Starting Watts | Overnight (10h) kWh |
|---|---|---|---|
| 1/3 HP | 500 - 800 W | 1,200 - 2,200 W | 0.0 - 0.9 |
| 1/2 HP | 700 - 1,100 W | 1,600 - 3,000 W | 0.0 - 1.4 |
| 3/4 HP | 900 - 1,400 W | 2,200 - 3,800 W | 0.0 - 2.1 |
Practical Example
If your pump runs 70 minutes overnight at 850 W:
- Energy = 0.99 kWh
FAQs
Do TOU rates help with sump pump costs?
Sometimes, but weather-driven runtime is the main factor.
Is surge lower overnight?
No, startup demand is similar.
Should I monitor pump runtime?
Yes, runtime logs improve backup sizing accuracy.
CTA
Ready to size your setup accurately? Use the WattSizing Calculator to estimate panel, battery, and inverter requirements from your real appliance loads.
