I believe I understand the difference between Full-Rated (and) Up-rated pumps, and I've read the excellent post on them @TFP, however, I've always wondered whether an up-rated pump would be more energy efficient than a full-rated pump, considering the motor in an up-rated pump is smaller yet it pumps the same volume. OR... whether the up-rated motor is working harder, it would be equal or worse in efficiency?
Reason I ask, I'm replacing my recirculation pump and I'm looking for energy efficiency.
I don't want to go with the expense of a 2-speed pump, but I'm hoping to determine the most efficient route with a conventional pump.
We have a 1,000 gallon swim-spa. Our original pump (Whisperflo 1.5HP SF=1.1) cycles the entire spa about 4 times in that 45 minutes. I had originally chosen the 1.5HP, because it appeared to be the best amperage-to-pump volume ratio. However, I'm now wondering if I went too big, based on articles that claim that a smaller pump will be more efficient, with all volume being equal (eg 5k gallons of recirculation is going to be less total amp hours for a 0.5 HP pump than a 1.5 HP pump, in what I've read).
In my application, the recirculation plumbing is 2", with roughly 60' of head (including all elbows), behind the pump is a Hayward 2400 DE filter, which I believe may be too small for the 1.5 HP pump as well.
This is for recirculation only (unless you count using it for a vacuum line).
The only real value the larger pump offers, being the better suction when using it as a vacuum. Other than that, I'd prefer to go with energy efficiency above all else.
Thank you in advance for any ideas,