Water Vapor Transport into Conventional Insulation Materials
Insulation materials with high permeability become saturated with moisture up to the volume of relative humidity of surrounding air.
Not a problem in very dry conditions. However, in most of the world that translates to 40-60+% relative humidity and simply a matter of time before almost all mass-based insulations are saturated to the local relative humidity level. We understand heat transfer at higher humidity levels based on the relative discomfort a higher humidity environment has versus a low humidity climate at the same temperature. A 90F day at 50 RH is obviously more comfortable than a 90F day at 90 RH. It's because the higher moisture content climate is transferring heat more effectively.The coating will not accept moisture and can retain its low heat transfer characteristics indefinitely. The following chart shows the permeability of various type of traditional insulation materials:
NEED TO BE FINISHED