Window Performance and Building Energy Use: Some Technical Options for Increasing Energy Efficiency

Window system design and operation has a major impact on energy use in buildings asswell as on occupants thermal and visual comfort. Window performance will be a functionsof optical and thermal properties, window management strategies, climate and orientation,sand building type and occupancy. In residences, heat loss control is a primarysconcern, followed by sun control in more southerly climates. In commercial buildings, thesdaylight provided by windows may be the major energy benefits but solar gain must bescontrolled so that increased cooling loads do not exceed daylighting savings. Reductionssin peak electrical demand and HVAC system size may also be possible in well-designedsdaylighted buildings.