In this study, energy rating of different window glazings, available in the Indian market, has been carried out. This rating is helpful in selecting the best window for a given building and a given climate. It is shown that savings by a window w.r.t. the base window (single glazed, clear glass, 6 mm thick), depend upon window type, its orientation, climatic conditions of the place, buildings dimensions and thermal transmittance of its walls and roof. The study has been performed for five different climatic zones of India. Ten types of windows have been studied which include clear glass, tinted glass, low-e coated and solar control windows. Three types of buildings are considered with U-value of their walls ranging 0.52-2.07 W/m(2)K and U-value of their roof ranging 0.54-2.34 W/m(2)K. Finally, regression analysis is performed to develop energy rating equations for different glazings, buildings and climates. (C) 2009 Elsevier Ltd. All rights reserved.