[Porsche-O-Phile]

There are concerns about VFDs now starting to come to light that deal with eddy current creation in motor bearings and other components. This probably isn't a huge deal for a residential pool pump and the fixes are supposedly relatively straightforward (grounding rings, non-conductive bearings, things like that) but in some applications it can be a huge deal. I'm running into this now involving exhaust AHU fans serving a critical lab building.

VFDs are generally a good technology but there are quirks related to using them that aren't readily obvious or fully understood by many engineers (ask your EE if he or she has reviewed or commissioned a harmonics study for whatever facility they intend to install them in before doing so - if they look at you like you have three heads, run away). Also make sure that any pumps and motors are specifically rated as VFD compatible so you can get a warranty later if there's an issue and not end up potentially buying them twice.

Ahh, the joys of new high-tech stuff in buildings...