Sump pump
How much electricity does a sump pump use?
800–1,200 W · intermittent · $5–$15 per month in wet season
Most sump pumps are rated 1/3 to 1/2 horsepower, which translates to roughly 800–1,200 W while running. The uncertainty is entirely in how often they run.
Estimating real runtime
A pump cycling every 5–10 minutes during a storm might run 2–4 hours in a day. A pump in a dry basement in summer might run for two minutes total. The difference is two orders of magnitude.
The practical approach: watch it during your wettest month, count cycles per hour, and multiply by the pump's run time per cycle (typically 10–30 seconds). Then use the average across the season.
What matters more than energy
Sump pumps are a reliability decision, not an energy one. A failed pump costs tens of thousands in water damage, while the electricity costs a few dollars a month. Priorities:
- Test it quarterly by pouring a bucket of water into the pit
- Have a battery backup — storms cause both high water and power cuts, which is exactly when you need it
- Check the discharge line for freezing in winter, a common cause of failure
Continuous vs intermittent
If your pump runs continuously rather than cycling, that is not an energy problem — it means the pit is not draining, the float is stuck, or the check valve has failed. Investigate before the motor burns out.
Frequently asked questions
How many watts does a sump pump use?
800–1,200 W. The figure on the rating label is the maximum draw; actual use varies with settings, age and usage pattern.
How much does it cost to run a sump pump per month?
With the defaults above it comes to the monthly figure shown in the calculator. At 16.5¢/kWh — the US residential average — that is a realistic middle estimate. Your own bill may be 30% lower or higher depending on state.
Is it cheaper to run a sump pump at night?
Only if your utility offers a time-of-use plan and you avoid the 4pm–9pm peak window. On a flat-rate plan, the time of day makes no difference to the total.
Does the calculator account for real-world duty cycles?
Not automatically — you enter the effective hours yourself. For compressing appliances like refrigerators and AC units, enter the running watts and roughly the proportion of time the compressor is on, which is usually 30–50%.
Will a newer sump pump actually save money?
Compare the kWh figure in the calculator against an Energy Star model's stated annual use. If the difference is a few hundred kWh a year, the payback on a replacement is usually long; if it is over 500 kWh, it is worth pricing out.