To achieve successful commercialisation of new advanced windows and solar facade components for buildings, the durability of these need to be demonstrated prior to installation by use of reliable and well-accepted test methods. In Task 27 Performance of Solar Facade Components of the IEA Solar Heating and Cooling Programme work has therefore been undertaken with the objective to develop a general methodology for durability test procedures and service lifetime prediction methods adaptable to the wide variety of advanced optical materials and components used in energy efficient solar thermal and buildings applications. As the result of this work a general methodology has been developed. The proposed methodology includes three steps: (a) initial risk analysis of potential failure modes, (b) screening testing/ analysis for service life prediction and microclimate characterisation, and (c) service life prediction involving mathematical modelling and life testing. The applicability of the working scheme to be employed in the development of durability test procedures has been analysed for selective solar absorber surfaces and polymeric glazing materials in flat plate solar collectors. The examples show the great applicability of the general methodology for accelerated life testing. This will allow much shorter development cycle times for new products and will allow improvements to be identified and readily incorporated in new products prior to market introduction. (C) 2004 Elsevier B.V. All rights reserved.