After seeing several questions on pool pump efficiency and energy cost comparisons, I thought it might be helpful to put together a simple spreadsheet that allows a pool owner to compare the costs of several pool pumps. This spreadsheet uses the data from the California Energy Commission web site which shows the energy efficiency of many different pool pumps.

Pool Pump Energy Cost Comparison Spreadsheet Documentation:

Tabs

Pump Data - Downloaded CEC data with a few corrections
Scenario1 - Tab where the user enters data and sees the outputs. Currently filled with example data.

Enter in the pump that is to be compared to all others in the first column. Generally, this is the worst efficiency pump or the current pump. All user inputs are in yellow. Reference values are in grey, and calculations have no color.

More columns can be added to each scenario tab if you wish and you can also create any number of scenario tabs.

Inputs

1) Pump model # - It might be helpful to look at the "Pump Data" tab to find the pump first. Note that there is a separate pump model # for low speed of muti-speed pumps.

2) Relative Pump Speed (%) - Used to change a pumps speed from the nominal. However, it is more accurate to set this parameter to 100% and use a low speed profile rather than set the high speed profile to 50%.

3) Pluming Curve - Curve A is equivalent to 1.5" plumbing with single runs but it is probably the closest to most plumbing systems although it is a bit pessimistic on energy efficiency. Soon the CEC will add Curve C which is equivalent to 2" plumbing but I have added an extrapolated version in the mean time.

4) Pool Volume in Gallons

5) Average turnovers per day - If you change run times by time of year, use a yearly average

6) Energy Cost per kwh - This should be the marginal cost (highest tier) you pay for electricity

7) Pump Cost - This is also used in the total cost calculation and in the pay off period

8) Study period in months - This is for the total cost calculation

Outputs

1) Pump Row - Is the row number on the "Pump Data" tab

2) Baseline GPM - Unadjusted GPM from the CEC table.

3) Baseline Gallons/Watt-hr - Unadjusted efficiency of the pump pulled off the "Pump Data" tab and used in most of the energy and cost calculations.

4) Baseline Head - Unadjusted Head calculated from the curve type.

5) Variable Speed Offset (W) - Used in energy calculations

6) Adjusted GPM - Adjusted for RPM speed

7) Adjusted Head - Adjusted for RPM speed

8) Adjusted Watts - Adjusted for RPM speed

9) Adjusted Gallons/Watt-hr - Adjusted for RPM speed

10) Runtime (hrs) - The pump runtime for the given turnovers per day

11) kwh/Turnover - Energy consumption for one turnover of the pool

12) kwh/Month - Energy consumption for the number of specified turnovers and for an entire month

13) Energy Cost per Month

14) Relative Energy Cost per Month - Relative to the first pump

15) Study Period Total Costs - Energy plus pump cost over study period

16) Study Period Relative Total Costs - Relative to the first pump

Plumbing Types

Curve A is approximately equivalent to a pool with 2" suction/pad lines (or 2x1.5") and 1.5" return lines with 55' runs. Not too unreasonable but still not a great design.

Curve B is approximately equivalent to a pool with 1.5" suction/pad lines and 1.5" return lines with 190' runs. A worst case.

Curve C is approximately equivalent to a pool with 2.5" suction/pad lines (or 2x2") and 2" return lines with 100' runs. Reasonable design and I will updated the spreadsheet once they have the data.


Note too that this assumes your run speed is always the same which may not be true so you might want to look at two speeds (only what is available) and combine them.

Hoepfully, you will find this useful and please let me know if something isn't clear.

Hi Mark this is great data, unfortunately I do not see my pump model listed. My pump is a StaRite model P2RA5F, 1.5 hp. Do you know which model I could substitute this for????

The JWP5FL-6A1 should be close enough.

Also, I found an error on the Scenario2 tab so delete that tab and duplicate Scenario1 if you need to.

Pretty nifty table for a quick comparison of pumps. I have a couple of questions:

I.) The "Pluming (sic) Curve - Curve A" is selectable across row 2 --- should the drop downs for columns C, D & E also be used for input? They seem to work independently: though they are greyed out, one can select Curve A or Curve B in any of the columns, changing the output.

II.) In the post you've documented both Curve A and the vaporware-like Curve C, so what does Curve B apply to?

Thanks ---polyvue

Currently, all the columns are tied to column B for the plumbing input to force the same plumbing for all pumps. You can select a different plumbing for each column but I saw no reason to do that. If you are comparing pumps, they should all be on the same plumbing.

Curve A is approximately equivalent to a pool with 2" suction/pad lines (or 2x1.5") and 1.5" return lines with 55' runs. Not too unreasonable but still not a great design.

Curve B is approximately equivalent to a pool with 1.5" suction/pad lines and 1.5" return lines with 190' runs. I'm not sure why on earth they even put Curve B in that table but is a worst case.

Curve C is approximately equivalent to a pool with 2.5" suction/pad lines (or 2x2") and 2" return lines with 100' runs. More reasonable but may take some time to collect the data so it could be a while before they have that.

OK. But the data for Curve C doesn't yet exist, right? So, little help there. And what makes those yokels at CEC believe that a typical home run is 100'?! I think 20' is pushing it on my system. Would think they'd have at least halved this figure to a more reasonable 50'...

For precision, I think I'm going to have to go back to some of your original calculations -- will mull these over and get back to you. Thanks!

You could just bump up the efficiency some to approximate Curve C. I estimate that the efficiency should increase by about 15% for Curve C over Curve A. Something better than Curve C might be 20% over A but I doubt it would get much better than that.

I will update the SS to allow you to add or subtract efficiency.

Edit - Updated

Updated the spreadsheet to use Curve C which is extrapolated from Curves A and B.

I also added a way to change speeds for a variable speed pump.

Mark, this grid is great - thanks for sharing your work with us!

Regarding this statement, if I wish to compare my current pump (Pentair WF28; ss up rated 2 hp, unlisted in your ss) to the two speed version (WFDS28), would it be a reasonable to simply compare the WFDS28 high speed to the WFDS28 low speed? Further, should the relative pump speed be left at 100% for both high and low?

Nominal speed is what ever the profile dictates. So 100% for high speed profiles is 3450 RPM and 100% for low speed profiles is 1725. You can set 50% on a high speed profile and it will approximate the low speed profile but using 100% on the low speed profile will be more accurate. The speed parameter is mainly for the variable speed pumps.

In your case, since there is no profile for a WF28, you can use the WFDS28 high speed profile as a proxy. However, you might still want to have three separate profiles for comparison. For two speed pumps, it is likely you will split the run time between the speeds so for example, you could have the following profiles:

Profile 1: WFDS-28 (HIGH SPEED) @ 1 turnover per day (reference pump)
Profile 2: WFDS-28 (HIGH SPEED) @ 0.5 turnover per day
Profile 3: WFDS-28 (LOW SPEED) @ 0.5 turnover per day

You then add the cost of 2 & 3 and compare it to 1. Also, you can split the run time anyway you want for profiles 2 & 3 but it is more realistic to model it this way. Also, if you split the pump cost between the run times proportional to the run time, then you can just add each of the cost parameters for the two speeds and the totals will be correct.

I updated the spreadsheet with a two speed summary to show you how to set it up (see Scenario #1). Also, I had to fix the run time calculation as it didn't take into account the turnovers per day.