Energy Efficient Pool Pump

[mas985]

Can you run salt water systems on 4 or so hours a day?

I can run mine on 4 hours per day at about 85% (2 hours in winter) so you might need a little more run time but it depends on your SWG output.

I read the technology of the vs pumps by itself makes them more energy efficient? True? Or is the savings only from running at slower speeds. Sounds like it still would not be worth the additional cost based on price difference between the 2 speed and vs.

Yes the VS is more efficient at all speeds but the savings may not be enough to pay for the extra cost of the pump during the life of the pump.

Here is an example of an economic study I did comparing various pumps with $0.10/kwh and 4 hour run time (1 hour high, 3 hours on low). It takes the Intelliflo over 130 months of operation before it becomes more cost effective than the two speed. The pump may not last that long given reported drive failures by other users and that fact that most pumps don't last that long. I didn't even include the surge protection for the Intelliflo which would make it much worse. The fact is that when energy costs are cheap, it takes a long time to pay for itself over a two speed. BTW, you won't see this type of analysis on Pentair's site because they want to get into the more expensive pump and so embellish the energy savings. Also, note the cost per month. If run properly, all the pumps are pretty cheap to operate. Yes the SuperFlo costs about twice as much to run but that is only $3.50 per month difference so it takes quite a while before that can add up.

[PoolDoc]

Very interesting, Mark. A couple of questions:

1. Why do you have the 2-speed pumps set to run for an hour on high, every day?

2. Why does do the two Whisperflo pumps have such different efficiency? (65% vs 51%)

3. What sort of motor does the Tristar have, to have such a good efficiency value? (I've heard some not good things about Tristars locally, in terms of reliability, though. Not sure how valid those reports are, but people seem to be having more problems that they would have with a SuperPump. But then the SuperPump may be the gold standard in terms of operational reliability.)

I didn't realize the motor efficiencies were that low, or that they varied so widely.

[mas985]

1) It is some arbitrary but most POs with two speeds find they need at least 1 hour per day at high speed for better skimming and a cleaner. Low speed usually doesn't work so well for both of those things including myself. I can't create a scenario that fits all pools so I make the workbook available for those who want to customize it: Pool SpreadSheets

2) Larger motor (>HP) generally have better efficiency only because they use larger wire to handle the current. Also, the motor type makes a difference. Anything with a run capacity such as a Permanent Split Capacitor (PSC) or a Capacity Start Capacitor Run (CSCR) motors are more efficient than the motors with just a start capacitor. But for the Whisperflo, the main difference is HP.

3) Depends on the TriStar. The standard two speed pumps have CSCR motors which have better efficiency. The TriStar VS is an ECM permanent magnet motor. BTW, what sort of problems are they having? I know Hayward has had some issues with bad seals over the years which a third party manufactures so unfortunately they get the bad rap for it.

[PoolDoc]

The TriStar VS is an ECM permanent magnet motor. BTW, what sort of problems are they having? I know Hayward has had some issues with bad seals over the years which a third party manufactures so unfortunately they get the bad rap for it.

I don't know. I got the reports second-hand from the assistant manager of the local wholesaler. Like I said, I don't know how indicative those reports are -- and in my experience, every pump comes off second-best compared to the SuperPump's reliability which has dominated this local market. But, I'll try to remember to ask him for details the next time I see him . . . when he has time to talk.

[BStone]

Thank you both! I think I have been running the pump much longer than needed based on information given by the installer. It sounds like Ben's recommendation is a smart one (2 speed). Thanks again and I will keep you posted on the results.