The thermophysical properties of interior insulation in cars can depend strongly on mechanical compression of the insulation. No data exists presently on such dependence for this insulation. The main aim of this work was to measure the thermal conductivity and specific heat of different car interior parts (seat cushion, back cushion and leather–foam cover) in a temperature range of -20°C to +60°C and at four different compression values of 0%, 20%, 40% and 60%. Due to complicated mechanisms of material’s structure deformation under compression, theoretical predictions of these dependencies are very complicated. Therefore, experimental results have both scientific and practical interest.