Robert,

I can't dig into this too much now. I did look, and there's not too much you can do with your existing pump -- it requires a special motor that is not available in an energy-efficient winding. Your options are a variable speed pump, or a two speed .

Generally speaking, VFD's are
+ slightly more efficient
+ easier to select (one size fits all)
+ easier to install (unless you pick one that MUST have an external controller)
+ much harder to program
+ more expensive
+ less reliable

Two speed pumps are
+ cheaper
+ more reliable (especially in areas with lightning)
+ more serviceable (lose a VFD motor, and you may as well replace the whole pump)
+ more complicated to install (for full operation a two timer time clock is required)
+ harder to select correctly -- you MUST pick the right one, for maximum efficiency.

Properly selected, both types are eligible for utility rebates, where they are available.

If you want to go further, you'll need to post exact details of your filter and any other equipment, and send photos of your piping, skimmer(s) and return(s) to poolforum@gmail.com