Windows are important in the workplace for both environmental and psychological reasons. Good glazing design can reduce energy outputs by lowering the requirements for heating or cooling; frame design can utilise more sustainable materials and those with lower embodied energy, such as timber and aluminium-clad timber. Windows are also important for the provision of daylight and a view, both of which have known psychological benefits, although glare and passive solar gain can be problematic. Three studies were undertaken to look at sustainability and comfort issues for a number of different types of multi-glazed windows. Focus groups and interviews with professionals were used to examine issues of sustainability and productivity. Four case study buildings were surveyed to examine the level of energy use for different glazing specifications. A post-occupancy survey was then used to examine the level of comfort in these buildings. Results showed that architects consider comfort and productivity in their designs, but consider sustainability less often. Surveys of energy usage showed that building design can influence the efficiency of multi-glazed windows; this result was mirrored in the post-occupancy survey where design factors influenced occupant comfort. The research concludes that comfort and productivity in the workplace is related more to design factors than to sustainability factors. (c) 2004 Elsevier B.V. All rights reserved.