How to estimate cost/savings?

samhorowitz

Bronze Supporter
Jan 28, 2020
29
FL
Current:
15,000 in-ground pool
non-function SWCG
Polaris 360 pressure-side cleaner
Century HST150 single-speed 1.5 HP pump

We live in an area with relatively cheap power (about 11 cents/kWh, no off-peak/peak distinction). We recently moved into a home with a pool, our first. I've been running the pump for 2 hours in the morning and 4 hours in the afternoon for skimming, cleaning, and chemical additions.

I am looking at replacing the SWCG cell (current candidate: CircuPool Edge-40) or putting in a whole new system since the AquaPure is both undersized and 15+ years old (and non-functional for several years at least). A robot is also on our wishlist. I'm wondering if it makes sense to switch to a variable speed pump.

We currently spend approximately $40/month on electric for the pump, I think, estimating from the specs on the label. I have no clue how to estimate how much savings we would get by switching to a variable speed pump (especially factoring in I'd potentially be running the pump longer for the SWCG). I was actually looking at the Century V-Green 165 motor replacement since the pump housing as far as I know is fine. I think that's a pretty easy replacement and I wouldn't have to do as much replumbing?

We have 3 return paths: the Polaris, 3 regular returns, and a set of bubbling jets around an in-pool bench. If the jets and the Polaris are both off, the pressure at the regular returns is painfully high. I usually keep the jets off (I think this helps keep the pH from creeping up as fast?), so if we turn the Polaris off when we're in the pool those three returns... well, if we forget where we are in the pool, we get blasted.

Anyway, I digress. How in the world can I figure out a rough estimate for the drop in power? I saw the "Have you Lost Your Head" thread and accompanying spreadsheets but that's way beyond what I can figure out.
 
I have a spreadsheet that will do the comparison for you in my signature. The output is similar to this:

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