A sample of the insulation material with the dimensions 45 × 45 mm × material thickness is laterally sealed with an epoxy resin. The back side of the specimen is attached to a cooling device to manage a dew-point undercut. The front side is exposed to the climatic conditions in the climate chamber with +23 °C and 65 % r.h. This produces a gradient of temperature and partial pressure, and consequently vapor diffusion into the material. The adsorbed moisture is condensing at the sealed back side of the material, where it causes an increase of relative humidity; hence, the moisture content inside the material sample is rising. Due to the increasing gradient of relative humidity, a liquid transport back to the front of the material sets in. Eventually, the opposing moisture fluxes will reach a dynamic equilibrium. To reveal the hygrothermal behavior of the material samples during testing, two modes of measuring are taken. Through periodic gravimetrical measurements, the moisture gain is analyzed and documented for the test period. The moisture distribution in the sample’s cross-section is measured periodically by using nuclear magnetic resonance spectroscopy (NMR). The test results are reproduced by numerical simulation to determine and adapt the transport coefficients.