Designers of commercial buildings must choose from a wide range of possible window materials and assemblies. This is an introduction to the properties and technologies that make up an energy-efficient window system.
Glass and Window Properties Primer
The the commonly used energy-related properties of windows are: insulating value (U-factor), ability to control heat gain from solar radiation (SHGC and SC), and visible light transmittance (VT). Various coatings, tints, and other glass surface treatments can affect the energy properties of windows. Explore the glass technology options listed to the left.
Glass technology is combined with a spacer system and a gas fill between the panes to produce and energy-efficient insulating glass unit (IGU). These IGUs are assembled with frame and operability options to form the complete window assembly. Explore the window assembly technology options listed to the left.
Most of the emerging glazing technologies presented in this section are available or nearly on the market. Insulation-filled and evacuated glazings improve heat transfer by lowering U-factors. Switchable glazings, such as electrochromics, change properties dynamically to control solar heat gain, daylight, glare, and view. Building-integrated photovoltaic solar collectors involving window systems not only generate energy but also form part of the building envelope.