
Originally Posted by
cruzmisl
I wanted to figure out how much money I would save monthly if I were to switch to a 2 speed pump. This calc is done under full load so it may be a bit off but should give a good estimate.
formula:A x V x hrs (per day pump is run) x 30 (# of days in a month) / 1000 to get kWH x price per kWH.
Anyway to spare the numbers I calculated my current 1HP Sta-Rite at $50.67 for every 30 days of use running 12hrs per day at .06 cents/kWH.
Swapping to a Pentair Whisperflo 2 speed pump running at low speed for 12hrs using the same numbers as above costs $11.67 every 30 days.
This is not exactly a fair comparison. Since low speed runs at 1/2 the GPM of high speed, generally you should run the pump twice as long on low speed. So either you are running your current pump too long or the new low speed two short. The most valid comparison is when you have the same number of turnovers between pumps & speeds.
Quite a savings assuming my calc's are correct. If it is correct the pump pays for itself in 10 months. Not a bad investment IMO.
From what I said above, it may be twice as long for payoff but still a good investment.
Joe
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