PERFORMANCE: Energy & Cost

Peak Demand

Proper window selection and design can reduce peak electricity and cooling loads, thereby avoiding costly peak demand charges and easing the need for new power plants. In addition, high-performance windows impact mechanical systems, not only contributing to reduced operation expense but also to potential equipment downsizing, saving capital costs.

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 electric peak demand for 4 scenarios in Chicago, south orientation, 40% window area, and 4 unshaded glazing types.


This image illustrates monthly gas and electric peak for the same 4 scenarios as in the previous illustration using the Facade Design Tool. COMFEN can show the peak demand annually, monthy for the zone, or monthly for the facade. Note that COMFEN reports the peak heating and cooling day for each scenario.


Facade Design Tool



Window Technologies

Case Studies

Tools & Resources