Energy rating of windows for the cooling season: a proposal for Europe

During the last decade, several countries worldwide established systems for the energy rating of windows, which allow for the direct comparison of different window products on a common basis and enable the consumers and designers to select windows with regard to their energy performance. Most of the existing methodologies do not take into account the influence of the windows on the cooling needs, but indicate only their performance during the heating season. However, at the present time the cooling performance is becoming a significant parameter for evaluating the overall building energy performance in Europe.Within this context the current paper attempts to propose a new system for assessing the cooling performance of the windows at a pan-European level. The paper starts with a brief presentation of the existing window energy rating systems found worldwide. In order to propose a new rating system which can be applied across Europe, climatic zones were defined. A detailed analysis of the energy performanc...