U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program

New and Underutilized Technology: Smart Windows

The following information outlines key deployment considerations for smart windows within the Federal sector. This information spans:

• Benefits
• Application
• Key Factors for Deployment
• Ranking Criteria
• Resources

Benefits

Smart windows are made of electrochromic glass, which uses electrical energy to transition between clear and darkened state to control light and heat gain. Darkened glass transmits less light and reduces heat gain, especially in dual-pane windows.

Application

Smart windows are appropriate for deployment within most building categories and should be considered in building design, renovation, or during window replacement projects.

Key Factors for Deployment

Window orientation is a factor that must be considered prior to smart window implementation.

Ranking Criteria

Federal energy savings, cost-effectiveness, and probability of success are ranked 0-5 with 0 representing the lowest ranking and 5 representing the highest ranking. The weighted score is ranked 0-100 with 0 representing the lowest ranking and 100 representing the highest ranking.

Resources

The following resources are available:

• Zero Energy Windows: Lawrence Berkeley National Laboratory (LBNL) article covering energy-efficient window technologies and applications.

• Advancement of Electrochromic Windows: LBNL online resource covering electrochromic window technologies, design, performance, and resources.

• COMFEN: LBNL tool designed to support the systematic evaluation of alternative fenestration systems for project-specific commercial building applications.

• Windows for High Performance Commercial Buildings: Design tool covering energy-efficient window integration.