Save electricity with a 2 speed pool pump

[gtojohn]

Great website, I'll try to contribute with what I know.
Swimming pools are awesome, but their upkeep requires a lot of power. Most pools are built with over sized pumps that use more power and waste energy because of head pressure and pipe resistance. For instance I have a 10,000 gallon pool it is common to see builders match up 1.5 hp motors for this size. I currently run a 3/4 hp pump that moves enough water for 4 return jets to break the surface of the water or move back the pool cover. In theory because I'm moving half water than the 1.5 hp I would need to double my run times. In practice I get by running the pump intermittently for 4 hours a day.

My current project is to replace my single speed 3/4 hp with a 2 speed 3/4. Low speed is 1/2 the rpm and flow but uses 1/8 electricity. This reduction is because the head loss from pipe resistance is minimal at lower speeds. I currently have a replacement motor on order, Ao Smith Century B2890. This motor line has a more efficient low speed than traditional motors. Price for the motor shipped is $270 and the energy savings should pay for itself within the first year.