Variable Speed Pump Savings
Measure watts and flow at the speeds you plan to use. Compare schedules that move the same daily volume and meet equipment needs. If there’s an annual saving, use an installed quote to work out payback.
Compare pump electricity costsCompare measured flow and watts at your electricity rate.
Compare Replacement Pumps
Compare replacement pumps at the flow your plumbing needs and your system head. Check electrical input at the speeds you’ll use, then include installation and warranty coverage when comparing prices.
Estimate turnover flow with the pump sizing calculator, then follow the selection checklist for flow at assessed head, electrical supply, plumbing fit, controls and warranty coverage.
Use supported scheduling controls. A timer that cuts power can interrupt the pump’s onboard schedule. Use the controls or compatible automation in your exact pump manual, and compare measured energy use before estimating a saving.
How Speed Changes Power and Flow
Under similar hydraulic conditions, the pump affinity laws approximate flow as proportional to speed and power as proportional to speed cubed. Slowing down reduces flow too. Motor efficiency and your system curve change the result, so measure electrical input and flow when comparing schedules.
At a lower speed, you may need to run longer to move the same daily volume. Keep enough flow for the salt cell, heater, filter and skimming, then compare electricity over the whole schedule.
An Electricity-Cost Example
| Single-Speed | Variable-Speed | |
|---|---|---|
| Example power input (assumed) | 1,125 W | 250 W |
| Daily runtime | 8 hours | 10 hours |
| Daily kWh | 9.0 kWh | 2.5 kWh |
| Seasonal energy (210 days) | 1,890 kWh | 525 kWh |
| Seasonal cost at $0.15/kWh | $284 | $79 |
| Saving only if daily service matches | (baseline) | $205 |
This example uses assumed watts and schedules over 210 operating days. To move the same daily volume, the 10-hour schedule needs 80% of the 8-hour schedule’s flow, within every equipment limit. Measure both operating points before treating the $205 difference as your saving.
Compare Your Pump Schedules
Enter your pool’s gallons, measured GPM and chosen turnover count for runtime. Add measured watts, your electricity rate and operating days for cost. Compare the other schedule at its own flow and power, then get an installed quote for payback.
Estimate Runtime and Cost →Choose Speed from Flow and Equipment Limits
Use the pump’s curve and measured operating points to choose speeds. At each setting, meet the flow limits for filtration, skimming, the heater, cleaner and salt cell. Measure watts and flow at those settings rather than using a generic RPM table.
Check Fit Before Choosing a Pump
Compare each replacement at the operating point your installation requires:
Installation fit
Match the electrical supply, union spacing and port size. Read the performance curve at your assessed system head, and include any plumbing or wiring changes in the installed quote.
Model and warranty checks
Confirm the model's status on the manufacturer's page. Read the warranty terms for your proposed seller and installer, including parts, labor and registration requirements.
Use the checklist: how to choose a variable-speed pump.
Frequently Asked Questions
How can I estimate annual pump electricity savings?
Measure watts and flow for both schedules, then compare electricity cost over your operating season. Both schedules need to move the same daily volume and meet the equipment’s flow requirements.
How do I calculate a pump replacement’s payback?
Divide the additional installed cost by the annual electricity saving for equivalent service. You need a positive saving for electricity-only payback. Use your actual season and installed quote, then consider maintenance costs separately.
Which efficiency rules apply to my pool pump?
Before buying, have an installer check the efficiency requirements for your equipment class and location. Take the selection checklist so you can ask about the exact model.
Estimate Cost for Your Pool
Use measured watts and flow for each schedule, with your electricity rate and operating season. For a replacement pump you haven’t measured, get performance figures for the proposed operating point before comparing its cost.
Pump Runtime Calculator →