Variable speed pump - min energy savings??

[jaimslaw]

What would be the out of box savings on, say, a 2hp intelliflo pump vs. a single speed 2hp, going head to head with same GPM and pressure? I saw a couple of fairly welll done youtube pump side by side comparisons of the intelliflo and the single speed, hooked up to electrical test meters and pressure gauges. In that video, it looked like that with both the single speed and the intelliflo outputting the same in the way of gpm/pressure, the intelliflo was operating with about 15-20% better efficiency (ie, an out of the box savings). But then I see posts by some claiming the intelliflo will be using 40% less in electrical consumption, again, with both outputting the same in the way of GPM and pressure. (And yes, I know far greater savings is achieved with ratcheting down the pump speed and increasing the operational time). I am sort of dubious about that 40% figure.

[chem geek]

When you hear savings of 40% at the same GPM and pressure, that's talking about 2-speed pumps on low-speed or if a single-speed pump, then a very low HP pump both compared to the IntelliFlo set for the same low speed. The IntelliFlo isn't particularly efficient at high speeds, but really shines at lower speeds. When I switched to the IntelliFlo for my own pool, I did get around 200-300 Watts savings at high speed by tuning the flow rate down somewhat for my solar panels (48 GPM, 3000 RPM, 1500 Watts), but if I ran at the same flow rate as my older pump the IntelliFlo would actually use somewhat higher energy (because my old pump was designed for high head -- 54 GPM, 3300 RPM, 2000 Watts for the IntelliFlo vs. 1800 Watts for my older Jandy HHP 1 HP 1.65 SF pump), but the really big savings was around 1400-1500 Watts when my solar system is off (26 GPM, 1500 RPM, 275 Watts). I also got rid of a booster pump for the pool sweep and instead use the IntelliFlo with The Pool Cleaner (15 GPM, 2200 RPM, 540 Watts). Overall, I save around 50% overall from around $1600 per year to around $800 per year (my marginal electricity rate is high at 40 cents per kilowatt-hour).

[CarlD]

2 hp? How big a pool? 45,000 gallons with an attached spa? Wow! Unless it's that scale in size it's WAY too much pump! More HP in a pump is NOT like a car. It's not necessarily a good thing and can be a really bad thing. I run a 1hp 2 spd pump on 19,000 gallons and not only does it work well, it works BETTER on low speed (I have a 200# sand filter). Yeah it runs longer but sand filters do much better when they aren't running near-capacity.
Carl