Why slow is cheap
Pump energy use does not scale in a straight line with speed. Cutting RPM roughly in half cuts flow roughly in half but cuts power draw far more steeply, so moving the same total volume of water at a lower speed uses a fraction of the electricity.
That is the whole argument for variable speed. It is not that the pump is magic; it is that you can move the water you need to move during many quiet, cheap hours instead of a few loud, expensive ones.
Turnover is the goal, not hours
What matters is circulating roughly the pool's volume through the filter each day, not hitting a number of hours somebody quoted you. A 20,000-gallon pool needs the same turnover whether the pump gets there in eight hours or fourteen.
Some jobs need higher speeds anyway: running a suction cleaner, priming, heating, skimming heavy debris, and running spillovers or a spa. Good automation runs a low base speed and steps up only for those tasks.
Seasonal schedules for Central Texas
Summer needs more circulation: high heat, high UV chlorine loss, heavy bather load, and algae pressure. This is when skipping runtime shows up as green water within days.
As water cools through fall, biological demand drops and runtime can come down with it. In winter, most pools here need far less circulation than in July — but not zero, because we stay open year-round and freeze protection has to be able to run.
Freeze nights are the exception to every schedule. Below roughly 37–40°F most freeze protection kicks the pump on regardless of the timer, and that is exactly what you want it to do.
Setting it up without guessing
Find the lowest speed that still skims well and keeps the returns moving. Below that point the water is technically circulating but the surface stops cleaning itself.
Watch filter pressure. A rising baseline means the filter is loading up, not that the pump needs more speed.
Re-check the schedule at each season change instead of setting it once at install and leaving it for five years.
You may not have a choice anymore
Since the federal Department of Energy rule for dedicated-purpose pool pumps took effect in July 2021, manufacturers can no longer build most single-speed replacement filtration pumps above the small horsepower cutoff. In practice that means when your main filter pump dies, its replacement will be a variable speed unit.
This is a manufacturing standard, not a demand that you rip out a working pump. Your existing single-speed pump is fine to keep running until it fails.
The rule targets the primary circulation pump. Booster pumps for pressure-side cleaners, and small dedicated water feature pumps, are treated differently and can still be single speed.
The upside is real: the replacement almost always costs less to run than what it replaced, and the difference on a Central Texas summer bill is not small. Pump swaps stay inside plumbing and wet-side work; anything touching the panel or high voltage goes to a licensed electrician.
