Certified pumps / Pentair

Pentair WhisperFlo VST

In-ground, self-priming filter pump, variable-speed. ENERGY STAR certified with a weighted energy factor of 8.4 kgal/kWh against a 5.45 minimum for its size class, from the record published 2022-02-22. Sold as 011533, EC-011533.

How its efficiency compares

The rail below places this pump against the 320 variable-speed in-ground records in the certified list and against the closest-sized pumps of any speed class. The tick is the median reported WEF for all 330 certified in-ground pumps, 8.6 kgal/kWh.

What it draws to move water

Certified specification

Rated motor horsepower and rated hydraulic horsepower are different quantities. Hydraulic horsepower is the water power the pump actually produced in the test; motor horsepower is a nameplate rating that includes the motor's own losses and any service factor. Two pumps sold as "1.5 hp" can differ by more than a factor of two in hydraulic horsepower, which is why this site sizes and compares on hhp and flow.

What it costs to run

The scenario below is this site's editorial default, not a figure from the certified record: 10 hours a day at the low-speed measured point, 2 hours at the high-speed measured point, and standby for the remaining 12 hours, at 18.31¢/kWh — the u.s. average retail price of electricity to residential customers for July 2026. Change any of it in the cost calculator, which opens with this record's own figures already in the fields: 90.08 W at the low-speed point, 1053.99 W at the high-speed point and 2 W standby. Nothing on this page is an estimate, and neither is anything the calculator starts from — the hours, the electricity price and the season length are the only editorial numbers, and all three are yours to change.

These are arithmetic on the certified watts, nothing more. A pump installed in your plumbing sits on a different system curve than the test rig, so its real draw at a given speed will differ. Measuring at the panel or with a clamp meter is the only way to know your own number.

Comparable certified pumps

Certified in-ground pumps within 0.2 hydraulic horsepower of this one, best WEF first:

Next: work out whether this pump's flow turns your pool over often enough with the turnover calculator, prefilled with its 31.19 gpm low-speed measured flow; compare it against another certified pump at one electricity price in the cost calculator's side-by-side view; see the other Pentair records held in detail; read what the weighted energy factor does and does not tell you; or check the methodology for every source and assumption behind this page.