I know my 2hp well pump gpm/psi is too much for the 4 ton GSHP arriving next week. I've read about the potential energy expense of CSVs vs. upfront expenses of variable flow pumps. My well pump was replaced only two years ago so I'm loathe to replace it but the Franklin Monodrive XT seems like a great solution to this all too common problem. It would appear this device will convert my three wire pump to variable flow by changing the frequency. I have two questions: 1) What will this do for efficiency? Information elsewhere suggests variable flow can actually use more electricity though this may be related to CSV marketing... But even Franklin's own material doesn't say much about saving energy, it's about constant water pressure with varying use. 2) How reliable is the Franklin unit? Any experience out there? It wouldn't make sense to spend $600 on this controller if it is short lived or particularly sensitive the vagaries of line power... Thanks for your input.