Is a variable speed pump worth the investment?

Apr 25, 2012
18
Sonoma CA
Hello:
I have a small in-ground pool in my backyard. It is 12' x 20' with a six foot deep end and about 3' shallow. I estimate it to be about 10,000g. The pool was built in 1978 and I had it re-plastered about three years ago. I would like to replace the original equipment pump this spring. I have an 8 year old Sta-rite cartridge filter. I am wondering if a variable speed pump is worth the extra expense? I have no heater or solar so I don't anticipate I need much more than 3/4 hp if I go with a single speed pump. We swim from about April to September. I cover the pool and shut everything down during the off season to save energy. I run a Polaris 360 Vac off the main water outlet from the pump so possibly looking at 1 hp. I'm having a tough time swallowing the $800-$1000 cost of a V.S. Pump, while I can get a Whisper-Flo Plus 1hp for >$300.
Our costs per ka hr in the Bay Area is $0.202, I believe we are on a sliding rate system where if decreases in non peak hours. Pool plumbing is 1.5" except all the above ground pipes around the sta-rite filter, which were converted to 2". No dedicated line for Polaris, runs off the main return line coming from the filter. My goals are two fold. Pump and impeller are nearly 34 years old, so Im afraid it can die any time. Second, we need to get a handle on our household expenses. We've been here 8 years and in that 8 years inflation has skyrocketed, food, gas utilities, kids, and our salaries have not. I run filter only 4 hours in the non peak hous at night and then we have it on when we swim. Water quality seems fine, tests fine. Thanks again.
--John
 
The VS pumps are kind of an interesting animal ... very expensive, but very versatile. They really can be desirable if you have many different water paths that you want to be able to tweak the flow rates (waterfall/water jets/spa/cleaner/solar/etc).

It sounds like your system is pretty basic with just a pool needing circulation/filtration and a pressure side cleaner. A 3/4HP 2-speed could be a good option where you could use high speed for the cleaner and low speed for circulation/filtration at only a small increase in price over the single speed. Low speed has roughly half the flow rate using 1/4 the power of the high speed.

Arguments for the VS are that you could set the minimum speed required to run the cleaner and save electricity when it was running. Also, they can be run at lower flow rates using less electricity than the low speed of a 2-speed pump for circulation ... you can tweak it so that you have good skimmer action at the lowest possible speed.

What you have to try to decide is the extra ~$400 for the VS worth the versatility and will it save enough power costs to make up for the extra upfront cost. Your cost seems to be right around where the electrical savings makes sense for the VS pump, but your break even point may be a few years out.
 
John, like Jason said your right on the bubble of 2 speed and VS pump. I guess you also need to ask yourself are you planning on staying in the house the next 5-6 years? If you are then the next thing I would say you know electricity rates are not going to go down so if your budget allows the VS it will save you the most.
 
Thanks for the replies, guys. You reconfirmed about what I was thinking. I am probably leaning towards a duel speed pump, but a variable speed isn't out of the question. I will also check with our power company to see what kind of rebates would be offered. I am thinking between a PG&E rebate and a possible IRS tax break for energey improvements I could shave a couple hundred off the purchase price. I welcome any suggestions for a duel speed pump brand recommendation.
--John
 
The Pentairs are nice pumps. You can get 2-speed Whisperflo that move a lot of water. Or the Superflo is a little smaller for pools with smaller pipes. I too have all 1.5" pipe underground and will be getting the 1HP Superflo 2-speed.
 
I checked out your recommendation and I think it would definitely fit my needs, the Super-flo. Just one thing, do you think I could get away with a .75 hp pump, with 1.5" pipes creating a little higher head pressure? I guess the bottom line would be does it create enough pressure to run the Polaris?
 
Realize that the 0.75 HP pump is 120V and the 1HP is 240V ... depending on what you currently have, you may have to change wiring.

I do not think the SuperFlo have a switch (hopefully someone will confirm). It is pretty straight forward to wire a toggle switch into the setup though.
 

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Go to the Pentair website and you can find all the model numbers and then Google them specifically.

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone :)
 
Ross939 said:
I'm not seeing any 2-speed .75 hp pumps out there, for inground... I'm thinking they don't make them?
In the Whisperflo line, the WFDS-3 (3/4 full rated HP) and WFDS-24 (1 up rated HP) have identical performance.

The Superflo SF-N2-3/4A is a 3/4 up rated HP two speed pump and has a much lower head curve than the Whisperflo. This means longer turnovers but less energy per turnover.

You can buy these here:
http://www.inyopools.com/pumps_pentair.aspx
http://www.tcpoolequipment.com/cart/ind ... 6_249_1140
 
Just something I've noticed for my pool...the skimmers barely work. If there is even a constant slight breeze the surface starts to get cluttered. For this reason I chose a single speed pump at the same (pool designed) HP and I find I only need to run it for about 4 - 6 hours to get my 1 turnover.

The only other concern for me would've been my heater requiring more flow hours, but if the flow rate goes too low it's efficiency would drop as well.

Bottom line for my situation...off is actually a little more convenient and an immediate savings.
 
Running a larger pump ends up using significantly more electricity, even though it runs for a shorter time. There are rare situation where you need a bigger pump to get the skimmers to work well, but that is quite uncommon.
 
Can someone advise me on this? I have a chance to pick up a 5 year old Pentair WhisperFlo Super Hi Efficiency 3/4HP pump. A guy down the road is closing up his pool and selling his equipment. He's asking $150. I am thinking about picking it up. It's still hooked up so he can demo it. My only concern is I probably wouldn't be able to run my pressure side polaris 360 off it? I suppose I can always go back to my suction side sweep. Does this sound like a good deal?
 

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