Here at CalArts we have a smattering of "techno-pianos." Unlike most of the other pianos in our inventory, we cannot put full humidity control systems on our MIDI-grands and Disklaviers, only drying rods and humidistats. It gets very dry out here, and for the heart of the school year.
So, we started using room humidifiers (Venta L45 Comfort Plus) in some of those rooms. VERY beneficial, but must be watered much more frequently than piano-specific systems.
In one of our classrooms, we have a piano with a complete PLSS on it. In that same room is a harpsichord (which seems to change pitch if you stare at it too long). We had a smaller capacity room humidifier on hand, one without a humidistat. (Since RH can vary 40-50% in a single day out here, we don't want a room humidifier operating without being humidistatically controlled.) As an experiment, we plugged the room humidifier into the PLSS humidistat's "Humidifier" side of things. The results after a few months are very promising. The harpsichord gets tuned at least once each week, and has been much more stable than usual. We were concerned that the room humidifier might need to be manually reset after being turned off by the PLSS, but that is not the case.Has anyone else tried doing this? Or anything akin to it? Might there be any potential downsides?