Energy and environmental life-cycle analysis of advanced windows

The environmental consequences of options for the manufacture, application, disposal, reuse and recycling, applicable to the Full range of currently conceived advanced window systems, are discussed. Advanced window systems may incorporate, singly and in various combinations: evacuated contiguously-sealed glazing, electrochromics, thermochromics, photochromics, aerogels, xerogels, inert gas filled double glazings, low infra-red emittance coatings, diffractive daylight deflectors, holographic daylight deflectors refractive daylight deflectors, toughened glass. The primary impetus for the development of such systems is that their use enables buildings to incur minimal energy use by reducing window heat losses and/or the displacement of electric lighting by enhanced daylighting The energy savings associated with advanced glazings displace the combustion oi fossil fuels directly and indirectly; environmental benefits thus ensue. However these benefits map be offset by the impact of energy embodied from manufacture and the negative impacts of the extraction and disposal of constituent materials. Over their total life-cycle the environmental impact for advanced glazing systems and their associated means of manufacture, system fabrication and the tenable reuse, recycling and disposal options are unknown. The usefulness of life cycle analyses during the research and development stage is discussed.