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Thread: Considering 2 speed pump? Here's a cost comparison.

  1. #1
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    Default Considering 2 speed pump? Here's a cost comparison.

    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.

    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.

    Joe

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    slowtan is offline ** No working email address ** slowtan 0
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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    great #'s

    It is actually a plan of mine to replace my pump w/a 2 speed pump but I am un-sure when I will actually get it done. Please PM me w/where and how much you are getting your pump for .. I am looking at a 1hp or 3/4hp.

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    CarlD's Avatar
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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    They also are nearly silent at low speed. Sand filters actually work BETTER because the water's moving through them slower.
    Carl

  4. #4
    duraleigh Guest

    Default Re: Considering 2 speed pump? Here's a cost comparison.

    Interesting numbers. What comes to my mind, however, is how much work you are getting done.

    If your single speed pump is sized correctly to your filter and pool, it should do the job it's intended for. For a 2 speed pump to do that same job, it would need to do it at low speed for you to realize the cost savings.

    So a 2 speed would benefit you only if you need the high speed to accomplish a task other than filtering. (Which, of course, would be quite frequently for many pools....but not all) Otherwise, you could simply use a single speed of the same power as low speed for adequate filtering.

    After all that, running quietly and efficiently are big, big pluses for 2 speeds and I believe they are a good value. I'm not sure the cost savings is as dramatic as it might appear.

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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    For me, I have a spillover spa, 2 stair jets and 2 pool returns. I typically only have the spillover spa going but if I have a party I want them all going. So for me during the week I can leave it on low speed to ciculate and filter the water but if I need more power I have it. No point in having a 1HP pump going 12hrs when I don't need to. Others could also use the 2 speed for vacuuming but I have a Dolphin and a Poolbuster so I don't need it for that.

    As for true cost savings, who knows. I do know the calc's made it easier to convince my wife we need a new pump

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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    I'm also considering a 2-speed pump and wondering if there is a substantial difference between brands. Is there any reason not to go with whichever brand of pump is cheapest? Are they all reliable? Why would I buy a Pentair 1hp 2-speed for $479.00 instead of this company's 1hp 2-speed for $335.00?

    http://www.electricmotorwarehouse.com/pool_pumps.htm

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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    Dave:
    Your premise is, at least for me, not valid.

    My use of high speed is primarily for backwashing. When I used a hose vacuum, I would need it then. But now with autocleaners and a PoolBuster, the hose vacuum's been the cellar for 2 years.

    I have solar panels and they work well with low speed. They ARE more efficient at high speed, but if the water is warm (89-90) why bother?

    I sometimes use high to circulate the water more--to make the skimmer more efficient or distribute chems faster. But generally, low is JUST FINE.
    Carl

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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    Quote 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
    See above comments.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  9. #9
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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    Well for me I am turning the water over more often than is necessary. My current pump flows 3600gph and the Whisperflo on low speed will flow 2100gph. I have a 15,000 gallon pool so on low my pool is turned over every 7 hrs or so whereas with my current pump it's turned over every 4hrs. I run my pump for 12hrs per day. I see no reason to turn my water over 3 times a day. It's a huge expense for nothing. The nice thing is if I want higher flow I simply flip a switch but for the most part I'm saving money and have less mechanical noise in the process.

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    Default Re: Considering 2 speed pump? Here's a cost comparison.

    So then a fair comparison for energy efficiency would be 8 hr run time for your current pump (2 turnovers) and 14 hours for the new low speed pump (2 turnovers). The cost differential then becomes $33.76/month vs. $13.62/month.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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