I have a small in-ground pool in my backyard. It is 12' x 20' with a six foot deep end and about 3' shallow. I estimate it to be about 10,000g. The pool was built in 1978 and I had it re-plastered about three years ago. I would like to replace the original equipment pump this spring. I have an 8 year old Sta-rite cartridge filter. I am wondering if a variable speed pump is worth the extra expense? I have no heater or solar so I don't anticipate I need much more than 3/4 hp if I go with a single speed pump. We swim from about April to September. I cover the pool and shut everything down during the off season to save energy. I run a Polaris 360 Vac off the main water outlet from the pump so possibly looking at 1 hp. I'm having a tough time swallowing the $800-$1000 cost of a V.S. Pump, while I can get a Whisper-Flo Plus 1hp for >$300.
Our costs per ka hr in the Bay Area is $0.202, I believe we are on a sliding rate system where if decreases in non peak hours. Pool plumbing is 1.5" except all the above ground pipes around the sta-rite filter, which were converted to 2". No dedicated line for Polaris, runs off the main return line coming from the filter. My goals are two fold. Pump and impeller are nearly 34 years old, so Im afraid it can die any time. Second, we need to get a handle on our household expenses. We've been here 8 years and in that 8 years inflation has skyrocketed, food, gas utilities, kids, and our salaries have not. I run filter only 4 hours in the non peak hous at night and then we have it on when we swim. Water quality seems fine, tests fine. Thanks again.