Experimental and numerical investigations to compare the thermal performance of IR reflecting insulation and mineral wool

Some manufacturers of IR reflective insulation products claim, that their products feature a high insulation quality that can not be described by traditional methods of building physics and their thermal efficiency may be determined by in-situ tests only. At an outdoor testing facility in South Germany two identical buildings in family house size are raised. In one attic a mineral wool roof system is installed, in the other an IR reflective insulation roof system. The insulation systems are chosen to have the same thermal efficiency according the declaration of the manufacturers. Both houses possess extensive measurement equipment in the attics for monitoring all important temperatures and heat flows. The comparative measurements of the attics are done during several winter and summer periods. Traditional laboratory measurements are made in an accredited test laboratory. The results of the in-situ and the laboratory measurement are compared. Further the examinations are completed by dynamic calculations. Therefore the simulation model is validated by the measurement data itself. In all measurements and simulations the examined roof system with IR reflective insulation shows typical characteristics of an insulation with lower thermal resistance. The values of the traditional measurements match very well with the results of the in-situ measurements. Conclusion of the measurements and simulations carried out is, that the IR reflective products can be described by the means of the traditional building physics.