How Much Does Pump Efficiency Matter?

[PoolDoc]

___________________________________

How Much Does Pump Efficiency Matter?

___________________________________

TL;DR:

The difference in electrical operating cost between efficient & inefficient systems can be huge, far more than I would have guessed.

Worst case is with an infloor cleaning systems and a single speed pump operating 24 hrs/day;
Best case is with no infloor system and a two speed pump operating on HI 1 hr/da and on LO 12 hrs/day.

Worst case? $2,748/yr or $230/month for electricity
Best case? $155/yr or $13/month.

The difference? Almost $2,600 per year!

Take home? A pool timer, even with professional installation, will pay for itself in less than 6 months of operation. Replacing a working 1 speed with a 2 speed will take several years to recover; replacing a broken pump with 2 speed instead of a 1 speed may take 24 months of operation.

Equipment examples at the bottom of the page.

___________________________________

OK, folks.

I've been driving myself nuts trying to work out optimized pump/filter/valve/piping sets for this page, Matched Pool Equipment Sets

I've done this dozens of times for large commercial pools. But the guys that make the big stuff publish the test data and flow data on their equipment in easy-to-find and easy-to-use formats. But residential equipment? They bury that information! It is HARD to dig it out and HARD to get it into a usable form.

So, for a break, I set up a simple test case, to compare pump ops on a simple standard pool:

30,000 gallons
2 speed pump
with or with/out infloor cleaning
$0.15/kilowatt/hour
63 gpm
20 psi base system head loss (46')
40 psi system head loss with infloor cleaning

Guess what? I am STUNNED at the results. I should have done this, years ago.

Here's a shocker: if you consider a basic 6 hour per day run, with an optimized Whisper Flo pump with an energy efficient motor, and compare it with a non-energy efficient Super pump . . . the differnce is significant, but not huge: $287 (90% elec. eff; 70% hydraulic eff) vs $406 (80% elec. eff; 55% hydraulic eff), but it's more than enough to pay the difference between a SuperPump and the more expensive WhisperFlo

The results of using Caretaker-like infloor cleaning systems is no surprise: I've long known that they were massive energy hogs. But the magnitude of the difference was surprising, at least to me:

___________________________________

Run time -- Run time ---- HP ------ Gallons
-- HI ------- LO ------- Req'd ----- circulated ---- $'s/day ------ $'s/mo ------ $'s/year

-- 24 ------- 0 --------- 2.0 ------- 90,000 -------- $4.24 --------- $127 -------- $1,624
--- 6 ------- 0 --------- 2.0 ------- 22,000 -------- $1.11 ---------- $33 ---------- $406
--- 1 ------- 12 -------- 2.0 ------- 18,000 -------- $0.43 ---------- $13 ---------- $155

___________________________________

With Caretaker

-- 24 ------- 0 --------- 2.0 ------- 90,000 -------- $7.53 --------- $226 -------- $2,748
--- 8 ------- 0 --------- 2.0 ------- 30,000 -------- $2.51 ---------- $75 ---------- $916

___________________________________

So . . . what's the difference between a well operated pool with a 2 speed pump, and a well operated pool with a Caretaker in-floor system? In electrical costs alone, the difference is nearly $800 per year!


And the difference between a well operated 2 speed system, versus a poorly operated Caretaker system is HUGE! You can hire a year round pool service company for less!
___________________________________