On the Measurements and Discrepancies Between Declared and Actual Thermal Performance of Reflective Insulation

Infrared reflective materials are increasingly used in building applications; however, their actual reflective performance is not always consistent with manufacturers’ claims. Reliable and accessible methods for evaluating their thermal and reflective properties are therefore needed. This study aimed to develop and validate a practical laboratory procedure for assessing the reflective properties of building materials. The proposed method combines comparative reflectance testing with measurements of thermal resistance. The procedure employs commonly available laboratory equipment, including a high-resolution thermal imaging camera and a plate apparatus used for thermal conductivity evaluation. Five commercially available materials with an aluminum reflective layer were tested using this method. The laboratory measurements showed good agreement with ISO standard-based calculations, confirming the reliability of the method. Among the five tested materials, only two exhibited the declared reflective properties. Scanning electron reflectometry analysis revealed that poor-performing materials either lacked aluminum particles in the surface layer or contained aluminum coatings that were too thin. The proposed procedure provides a simple and effective method for evaluating reflective insulation materials. The results demonstrate that not all products marketed as reflective insulation possess the required reflective characteristics, and that aluminum layer thickness and surface composition are critical factors affecting thermal performance.