2speed vs variable on new build

[Beer tunnel]

I want to raise this topic again as I'm still confused. I'm building a fairly basic ig pool with no major water features except a few deck jets. It will be about 15k gallons, no hottub, but most likely have solar heat. Is a variable speed pump worth the investment in my case? Is it true that they don't last as long as 2speed units? Why is that? My electricity is fairly cheap, less than 10 cents per kW hour, but running A/C in Florida is already got my bill near $200 in hot months so I don't want to add much to it if I can help it. Can someone "bottom line" this for me? All the hype on VS pumps compare them to single speed units, which aren't even an option here by code. So how do they stack up against 2speed pumps? What are some of the best makes and models?
Thanks for the help...


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[jblizzle]

With that cheap power, you will not likely recoup the extra cost of a VS pump over a 2 speed pump ... unless you get large rebate.

But the VS would give you a little more control to dial in flow rates for the deck jets and solar ... But this is certainly not a requirement.

Likely all you need is a small 1HP 2 speed like I have ... runs my large solar just fine.

 

[Isaac-1]

A variable speed pump makes things easier, as it allows for a certain lax attitude towards correct pump sizing, but is likely not the most economic choice out there. Chances are you would be better served with a 1 or 1.5HP 2 speed pump, if looking at installing roof top solar consider one with a medium or high head design.

 

[Beer tunnel]

With that cheap power, you will not likely recoup the extra cost of a VS pump over a 2 speed pump ... unless you get large rebate.

But the VS would give you a little more control to dial in flow rates for the deck jets and solar ... But this is certainly not a requirement.

Likely all you need is a small 1HP 2 speed like I have ... runs my large solar just fine.

Cheap power aside, how much more electricity will the 2speed use? Is the low speed plenty for your solar system? Is it true that 2speed pumps outlast variable speed? How much does yours cost you per month and what's your electric cost per kW hour?


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[Beer tunnel]

Also, who makes the best/most efficient 2speed?


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[jblizzle]

Answers in red below:

Cheap power aside, how much more electricity will the 2speed use?
Low speed moves 1/2 the water using 1/4 the electricity as on high speed/comparable single speed. So even doubling the run time on low to move the same water is a 50% electrical savings. A VS pump is slightly more efficient at all speeds, biggest advantage being it can run at even lower RPM for more electrical savings ... but you have to be sure you have enough flow for equipment and skimming to work.
Is the low speed plenty for your solar system?
I have accidentally left my solar on with the pump on low (before my automation was installed) and it seemed to work ok. BUT, solar heating is most efficient at high flow rates, so running it on low will not be as beneficial. You would certainly want to prime the panels on high speed to ensure all the air was removed. Personally, when I am running solar, I run on high speed. When solar is not needed I run on mostly low speed.
Is it true that 2speed pumps outlast variable speed?
I have no idea. 2-speed pumps have been around longer and there are no electronic components that could go bad being out in the weather ... but maybe the VS are fine.
How much does yours cost you per month and what's your electric cost per kW hour?
All fees and taxes included, I am at about $0.12/kW in the summer. I have no idea what the pump costs to run. Unless you get over about $0.20/kW or have large VS rebate, it may take 4+ years for the VS pump to save more in electricity to compensate for the higher initial cost. My 1HP 2-speed Superflo is less than $450. The larger VS pumps are around $900.
Also, who makes the best/most efficient 2speed?
There is no real best/most efficient I don't think. If you stick with the major brands they are all pretty comparable ... you will find people happy with any of them and your will find people that have problems with any of them.

 

[bobodaclown]

Beer Tunnel are you planning on any automation with your pool setup? I'm in Lakeland and originally had a single speed motor (1hp), I replaced it with a smaller (.75) motor, then picked up a 2 speed (.75/.3). I run 99% of the time in low and am very happy with it.

I don't think the VS will be cost effective in the long run. The savings in electricity won't cover the price difference.

 

[Beer tunnel]

Probably just a timer for the pump and a thermostat controlled valve for the solar heat. I like things simple..


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[jblizzle]

Probably just a timer for the pump and a thermostat controlled valve for the solar heat. I like things simple..

You would be better off making sure that whatever solar controller you buy to control the actuator ALSO has a timer and can switch the pump speed. The cheap solar controllers will only turn the solar valve on and off ... so you would have to leave the pump on high speed for when the solar turned on.

The small upgrade in getting the controller that will control the speed as well will quickly benefit when it can lower the pump speed to low when solar is not needed.

The Pentair Sun Touch I think would do everything you need.