Interior thermal insulation systems based on wood fiberboards: experimental analysis and computational assessment of hygrothermal and energy performance in the Central European climate

Abstract Two interior thermal insulation systems based on wood fiberboards are analyzed. The first system is composed of soft and hard fiberboards, the second one utilizes a capillary active fiberboard with incorporated water vapor retarder. The hygrothermal and energy performance of the systems in the climatic conditions of Central Europe is assessed using a combination of experimental and computational methods. A laboratory critical experiment is performed at first. The measured temperature and moisture profiles are then used for the validation of computational model of coupled heat and moisture transport, which is applied for hygrothermal and energy simulations. After the successful validation procedure, the model is used for the annual assessments. The energy assessment of the two-layer system shows excellent results from the point of view of energy savings (79 % improvement) but its hygrothermal assessment reveals possible shortages related to excessive hygric straining of the wall on the exterior side. The capillary active insulation system with water vapor retarder, which is able to keep moisture in the envelope within the hygroscopic range, exhibits only slightly worse energy performance (66 % improvement) but much better hygric performance than the two-layer system.