CSBR College of Design


The Impact of External Shading Devices in Commercial Buildings

Exterior shading devices, such as overhangs and vertical fins, have a number of advantages that contribute to a more sustainable building:

  • Exterior shading devices result in energy savings by reducing direct solar gain through windows. By using exterior shading devices with less expensive glazings, it is sometimes possible to obtain performance equivalent to unshaded, higher-performance glazings.
  • Peak electricity demand is also reduced by exterior shading devices, resulting in lower peak demand charges from utilities and reduced mechanical equipment costs.
  • Exterior shading devices have the ability to reduce glare in an interior space without the need to lower shades or close blinds. This means that daylight and view are not diminished by dark-tinted glazings or blocked by interior shades. With exterior shading devices, glare control does not depend on user operation.

To better understand these impacts, AMCA International has supported the development of a publication, External Shading Devices in Commercial Buildings: The Impact on Energy Use, Peak Demand, and Glare Control. The information in this publication is based on computer simulations done at Lawrence Berkeley National Laboratory for the U.S Department of Energy (DOE) Windows and Glazing Program. More extensive results are available in the book, Window Systems for High Performance Buildings, and at www.commercialwindows.umn.edu.


This AMCA publication is intended to help the designer quickly narrow the range of possibilities and understand the approximate impacts in commercial office buildings in order to provide general guidance during the early stages of design. If there is more time and budget, this can be followed by a more detailed computer simulation of the specific building and the design conditions.


Project: The Impact of External Shading Devices in Commercial Buildings
Principal Investigator: John Carmody
Project Team: Kerry Haglund
Sponsor: Air Movement and Control Association International (AMCA)
Status: Complete September 2006
Download Document: Full Report: The Impact of External Shading Devices in Commercial Buildings


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