A variable-speed pump provides the greatest energy savings. Running a pump at lower speeds uses significantly less power than running the same pump at a higher speed. In fact, in most cases, you will save more money running a pump at lower speeds for a longer period of time, than running at a high speed for a shorter amount of time. Plus your water will be cleaner and less susceptible to algae since the water is being circulated more often.
Two-speed pumps, which operate at two fixed speeds and require a separate automaton system to adjust between speeds, can save as much as 70 percent on energy costs over a single-speed pump. A variable-speed pump, which can operate at a wide variety of speeds—including those even lower than two-speed models, can save as much as 90 percent on energy costs compared to a single-speed pump. Some variable-speed pumps also include integrated timers to adjust speeds automatically for the task they’re performing. This means you’ll rarely have adjust the settings yourself and won’t need to buy a separate automation system.
Your actual savings will vary based on your pump model, hours of operation, electrical rate and other hydraulic factors.