To obtain traceable thermal resistance of radiant barriers for building insulation laboratory tests have been carried out. Heat flow meter apparatus and guarded hot box methods have been used. The heat flow meter method has been evaluated as a method to characterize the insulating layer itself, while the guarded hot box method has been used as a tool to determine the total thermal resistance of a building component including a radiant barrier. A material with both surfaces of reflective material has been used in the study. The measurements have been carried out using two configurations in the heat flow meter apparatus: simple air chamber and double air chamber. The results have been compared with a simple analytical model of heat transfer according to ISO 6946 standard and with a Computational Fluid Dynamic (CFD) model. The CFD model enables to assess the relationship between experimental and analytically estimated results. The main conclusion is that the laboratory tests are valid for the thermal characterization of radiant barriers. It also follows that thermal resistance of radiant barriers can be estimated with precision using the simplified ISO 6946 methodology, as long as values of the thermal properties of the reflective material such as emissivity and conductivity are reliable. (C) 2013 Elsevier B.V. All rights reserved.