When I remodeled my pool last year I purchased all new equipment.
Even though I'm in SoCal with the high electricity rates (.33 per kwh), I have no water features, no heater or solar (yet), no spa... so I got the dual speed 3/4 hp Whisperflo pump rather than the variable speed. Since my previous pump was a decades-old single-speed, I expected my electrical bill to decrease substantially but it really hasn't... so now I'm wondering if I made a mistake and should have gotten that variable speed pump after all.
I run the dual speed daily at high (3450 rpm) for 2 hrs then at low (1725 rpm) for 6 more hrs. I'm looking into getting solar heating installed and my understanding is that I will need to run the pump at high for a lot longer than 2 hours if I want to get the full benefit of the solar heat since running at low won't have as much impact (please correct me if I'm wrong). No doubt that will increase my electric bill even more!
The solar panels (8 4x12s) would be on my single-story roof, ~10 feet from the equipment pad which is also about 10 feet from the pool.
I'm assuming that it costs me more to run at higher rpm than at lower. Are the variables more energy efficient at 3450 rpm than the dual at high (3450 rpm)? If I remember correctly, I'd heard the variables are more efficient at the lower speeds... but if the dual-speed can't handle the solar thing at low, then why would the variable speed be any better at it? Unless the variable is significantly more efficient at the higher rpm of 3450, then maybe I am okay with the dual. Or maybe its the 6 hrs at 1725 that's costing me more and that's why I should consider a variable instead of the dual... I'm so confused!
And speaking of 3450, how would I determine what speed to run the variable at and for how long during the day to get the most out of the sun?
I have seen other postings with calculation numbers but they were greek to me. I have not been able to figure out what my rates are for the dual compared to the variable. Can anyone please help me, in layman's terms, figure that out? Specifically, how much it costs me per hour at high and per hour at low, on the dual vs the variable.
Many questions, I know! Gosh, it would be so much easier if these pumps just had bottom-line price tags on them... Thanks for your help!