Although window is the main medium for the lighting of the building, it contributes significantly in the building's energy consumption, either commercial or residential. In the general frame of a growing world population and consequently of an increasing demand for reducing energy consumption for building needs, the development of appropriate glazing materials towards the maximum reduction of energy losses or gains is a major pre-requisite of modern architecture and thus of intense research in recent years. In this review, new work on insulating, reflecting, electrochromic, thermochromic, photovoltaic, water flow-based and emerging innovative materials is presented in an attempt to reveal the benefits of each glazing category but also the required research needs for future development. High energy savings can be achieved by integrating innovative transparent components in the building envelope. Insulating materials have reached a very low thermal conductivity in their sensible heating and recent complex radiative cooling multi-coatings have proved that temperatures even below the ambient can be reached indoors. Glazing integrated PVs, are among the most promising solutions due to heating and cooling savings in addition to electricity production. Finally, the combination of different panes in double glazing windows can optimize the environmental solar interaction of windows and maximize building energy savings. (C) 2015 Elsevier B.V. All rights reserved.