Variable-speed pumps save money by running slow for longer — power drops with the cube of speed. Enter your pool and pump details to get an optimized daily schedule and your monthly savings versus a single-speed pump.
Pump affinity laws are the key: flow drops in proportion to speed, but power drops with the cube of speed. Run a pump at half speed and it moves half the water while using only about an eighth of the power. So moving the same volume slowly over more hours costs far less energy than blasting it through at full speed. This calculator sizes a multi-speed schedule to turn your water over once a day, then compares its energy cost to a single-speed pump moving the same water.
Flow at a given speed depends on your specific pump and plumbing, so enter your pump's rated flow and wattage at full speed for the most accurate result — the speed tiers then scale from there by the affinity laws. The default high/medium/low tiers are sensible starting points, not a fixed prescription; your pump's app or manual may suggest different RPMs. The savings figure compares against a single-speed pump moving the same water, which is a conservative baseline — real savings are often larger because single-speed pumps tend to run far longer than the minimum turnover requires.
Dropping from full speed to half speed cuts power to roughly one-eighth. Running twice as long to move the same water still uses far less energy overall — which is why variable-speed pumps pay back.