Comparison of Modified HFM and TBM Methods in Calculating the U-factor of Insulation Materials Using a Refrigerator

On-site measurements are more suitable than theoretical calculations for verifying the actual thermal properties of buildings. On-site estimates, in real conditions, can often deviate from estimates obtained theoretically, especially for older buildings and materials when considering aging and other environmental factors. One of the most important metrics for assessing the thermal efficiency of a building is the U-factor, and for its calculation in this paper we used modified measurement methods commonly known Heat flow method (HFM) and the temperature-based method (TBM). Measurements were conducted in laboratory conditions, at a controlled temperature, using a laboratory refrigerator. Polystyrene, Styrofoam and Skytech were used as insulation materials. The aim of this paper was therefore to compare two experimental measurement techniques that are often used in construction today: standardized HFM method and newer TBM method, which are described in detail. Also, the measurement results were compared with theoretical U-factor values for individual materials. We believe that this work can be a valuable source for both scientific and practical applications, as it provides better insight into the processes of measuring and calculating U-factors for materials that are most used in construction today.