PERFORMANCE: Energy & Cost


Greenhouse gases (GHG) are the gases present in the atmosphere and are essential to maintaining the temperature of the earth. Without greenhouse gases the planet would be so cold that it would be uninhabitable. Yet, an excess of greenhouse gases can raise the temperature of the planet to uninhabitable levels. Slowing the growth rate of GHG emissions is the key to reducing the effects of global warming. Since 76% of energy produced goes to operate buildings, these buildings are a major source of demand for energy and materials that produce by-product greenhouse gases. A major contributor to the GHG emissions is carbon dioxide (CO2). It is therefore necessary to reduce, and eventually eliminate, CO2 emissions from buildings.

Annual U.S. GHG emissions are projected to rise from 7.2 gigatons CO2e (carbon dioxide equivalent: the standardized measure of GHG emissions designed to account for the differing global warming potentials of GHGs) in 2005 to 9.7 gigatons in 2030—an increase of 35%. The growth of the emissions results from:

  • Continued expansion of the U.S. economy.
  • Rapid growth in the buildings and transportation sectors driven by population and consumptions increases.
  • Increased use of carbon-based power in the electric-power generation portfolio driven by the construction of new coal-fired power plants without carbon capture and storage technology.

Tools such as the Facade Design Tool and COMFEN demonstrate the environmental impacts of various design scenarios—allowing for decisions to be made early in the design process.

This image illustrates the annual carbon emissions for 4 scenarios in Chicago, south orientation, 40% window area, and 4 unshaded glazing types.


This image illustrates monthly carbon emissions for the same 4 scenarios as in the previous illustration using the Facade Design Tool. COMFEN can show the carbon emissions annually, monthy for the zone, or monthly for the facade.


Facade Design Tool



Window Technologies

Case Studies

Tools & Resources