Greater than 50% RH indoors is hideously uncomfortable, not to mention moist enough to grow all sorts of stuff. I just looked at a ranch house built in 04, a pole barn over a full basement with two zone hydronic radiant heat, completely clad in steel. My humidistat went berserk when I took it out of my pocket. In less than 20 seconds the readings went something like: 21, 34, 45, 62, 74, then froze on 88. I reset it twice and installed new batteries, same result. The homeowner had analog gauges in several rooms of the house reading 57 to 68% with indoor temps in the low 60's. It was so muggy in there that I broke a sweat doing an IR scan. And to think I was called out to diagnose a condensation problem[:-banghea