I replaced the impeller on my Jandy Zodiac FloPro FHPM 2.0-2 with a 0.75 HP impeller to try to get better energy efficiency. I was under the impression from what I'd read here that replacing a 2.0 HP impeller w/ a 0.75 HP impeller was equivalent for installing a 0.75 HP pump. I tested amps to see what kind of energy savings I was getting with the smaller impeller.
Results with clamp amp meter: 240 volts.
0.75 HP impeller: 3.0 in low-speed, 5.25 in high-speed
2.0 HP impeller: 3.2 in low-speed, 8.8 in high-speed
Seems like less savings than I would expect if I swapped a 2.0 HP pump for a 0.75 HP one. Especially less than 10% difference in low-speed.
Is this level of energy savings what I should expect dropping from 2.0 to 0.75 HP? If not, should I consider getting a variable speed pump or replacing my pump with a lower HP 2-speed pump?