Someone was telling me that there are new Variable speed (VFD) well pumps out now that save a lot of energy.
Anyone familiar with them? From what I have found there are some that are variable speed and eliminate a large pressure tank but really no talk of energy efficiency. the speed difference eliminates the pressure changes. It would seem to me that they would always be working against almost max pressure and thus be less efficient, but I might be looking at it wrong.

I say min pressure, but even so, not a lot of energy . Say your conventional tank varies from 30 psi to 50 psi. A variable speed pump could be held right at 30 psi.

IF it did hold to 30 then there would be some savings as it would never be pushing against 50 psi. Typically VFD's save a lot, but I just have not been able to find info on these.

I cannot fully speak on the savings because I don't know much about well pumps but I do work with ground source heat pump flow centers and a typical flow center for a 3 ton unit uses about 400 watts while a variable speed pump can flow more water at a higher head pressure and do it for about 120 watts. I can't tell you much more than that.

There is no free lunch in pumps. If you have a predictable load and a properly sized/rated pump, you will actually lose a little efficiency in the electronics of the VFD. A VFD is beneficial where the load is variable.