A concrete wall externally insulated with six expanded polystyrene boards, each containing three vacuum insulation panels, was investigated both experimentally and numerically. The main goal of this study was to determine the thermal performance of vacuum-insulation panels applied to walls in building constructions. Comparisons were made with conventional insulation and also with systems including damaged, i.e., vented vacuum panels. Since the vacuum insulation panels are encased in a metallized laminates as barriers against permeation of moisture and gas, special attention was given to the edge effects. Stepwise adjustment of the measured and calculated results reported here provide a general assessment of the efficacy of this insulation system applied on different wall materials. A functional representation of the measured data, for steady-state conditions, is introduced. Moreover, infrared thermography was used to confirm the three dimensionally calculated temperature distributions on the surface. The present investigation was part of the research programme "High Performance Thermal Insulation in Buildings and Building Systems" of the international energy agency (IEA). (C) 2005 Elsevier Ltd. All rights reserved.