2 speed pumps

Below is a chart I made - now the million dollar question is that do you really save if you need to run 2X on low to get he same filtering as 1X on high ??

Meaning these are both 4 hour run times 30 days...however do I need to run low speed more to get same results, thus eliminating the savings.

[attachment=0:2fz543a2]2 speed pump cost.jpg[/attachment:2fz543a2]
 

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Low speed moves 1/2 the water for 1/4 the electricity (The running amps are NOT what you have shown in your table). Even if you double the runtime on low that is still a 50% saving on electricity.
 
ethany said:
Do you really save much on your electric bill on low speed?
Yes. Low speed of a two speed pump has 1/2 the flow rate of a high speed. Therefore, the pump needs to be run twice as long to get the same turnovers per day. The energy used at low speed is generally less than 1/4 of high speed. So even when you run the pump twice as long on low speed, you are saving around 50 - 55% on electricity to run the pump compared to running it on high-speed for half the time.
 
toofast said:
Ok whew thanks...well I was certainly hoping my little calculation was wrong....just for fun, any idea where I find the running amps ? I pulled those numbers right from the tech specs of the pump.

It is not that simple ... I think it depends on the head loss that the pump experiences while at the different speed. Just trust the 1/2 flow at 1/4 the cost.
 
Well, since I happen to have your 1HP pump in Mark's tools for the other thread. Here are some numbers:
Using a cost of $0.125/kW and 4 hours run time:
High speed ... 4 hours/day = $0.55/day = $16.62/mo
Low speed ... 4 hours/day = $0.14/day = $4.24/mo .... double the run time and it is $8.48/mo

EDIT: Now whether I used the tool correctly or not ... who knows ;)
 
When our old pump fails I've considered a 2 speed, but Hubby keeps fixing the old one :| Saves the cost of buying a new one, but I'd like to see the energy savings... If I can get myself to spend the extra money on the 2 speed when the time comes.
 

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