Thinking about a variable speed pump swap, is it actually worth it on my setup

Started by Jason Okafor · · 3 replies
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#1
Single speed pump on my sand filter setup is still kicking but it's loud as hell and I know it's not cheap to run. Been reading up on variable speed pumps and the energy savings pitch sounds good but I'm trying to figure out if it's actually worth it for a 16x32 or if that's more of a bigger pool or spa combo thing.

Anybody here actually swapped a single speed for a VS pump on a similarly sized pool and noticed it on the power bill, not just in theory. Also curious how much of a pain the install is, if it's a straight swap on the existing plumbing or if you ended up redoing unions and fittings too. Not trying to get talked into something by a pool store markup, just want real numbers from someone who's done it. Your mileage may vary and all that but curious what people found.

3 Replies

#2
Jason, that "straight swap on existing plumbing" idea is the part I'd push back on, most single speed pumps have a different union spacing and sometimes a different pipe height than the VS models so you're probably cutting in a new union or two no matter whose pump you buy, not a bolt-and-go deal like the stores make it sound.

As for the bill, my brother-in-law's got a pool close to your size and he saw his power bill drop noticeable running the VS slow for filtration and only kicking up to high for the cleaner cycle, so it's not just a bigger pool or spa thing.
#3
still running single speed over here so no VS numbers to add, but the union spacing thing dave mentioned rings a bell, when i had my pump off the pad last year just to clean out the basket area i noticed mine wasn't even using matched unions to begin with, looked like whoever installed it just made it work with what they had on the shelf. wouldn't surprise me at all if a VS swap needed fresh fittings regardless of brand.
#4
I'll push back a little on framing this as purely a plumbing fitting problem, Dave's right about unions but the bigger number Jason should care about is run hours times watts, not install hassle. Single speed is usually pulling somewhere around 1500 watts whether you need full flow or not, a VS loafing along for an 8 hour filter cycle can be pulling a fraction of that, so the bill drop isn't some marketing trick it's just motor physics, in the trade we call it the affinity laws and it's real. On a 16x32 you're not some huge outlier pool where it stops making sense, I'd size it off your gallons and run the numbers on the pump run-time calculator here before you buy anything, the store markup is the warranty and install fee, not the pump itself.