Is there a way to estimate what the RH will be before service conditions are reached?

Yes, Wagner Meters offers the Service Temperature Adjustment Chart. It’s a science-based estimation tool developed by CTLGroup, a wholly-owned subsidiary of the Portland Cement Association. The chart is available for download and as a handy app that calculates the estimated RH for you. Check out both options here:

We’ve also built the Service Temperature Adjustment tool right into the Rapid RH® DataMaster™ app, just one more reason why the DataMaster™ makes RH testing easier than ever.