LAS VEGAS-Solar panels, insulated windows and energy-saving appliances all contribute to an energy efficient home. However, one of the most important factors in a sustainable home is often overlooked-its walls.

Attendees of this year's 2009 International Builders' Show® can see how different wall systems impact a home's energy efficiency and comfort by using a touch-screen computer system created by the Portland Cement Association (PCA).

The program, on display at the PCA booth (N2342), takes into account a house's size and geographic location to determine which construction material provides the lowest annual energy use. Users select a house type, concrete wall system, and area of the country. A results screen shows typical savings in electrical and natural gas, and also provides heating and cooling requirements.

"The materials used to construct the exterior walls of a home have a significant impact on the cost of heating and cooling it," says Brian McCarthy, PCA president and CEO. "For example, concrete's thermal mass absorbs heat during the day and releases it slowly at night when it is needed more, creating a comfortable home without extended use of the furnace."

The touch screen system reviews five house designs from 2,000 to 2,400 square feet in eight U.S. cities. It allows users to compare 11 different wall systems such as insulating concrete forms, wood frame with appropriate insulation, concrete masonry, autoclaved aerated concrete, or cast-in-place concrete walls. With this information, the program estimates the annual cost for heating and cooling the home.

Using data from a study sponsored by PCA and the U.S. Department of Housing and Urban Development, the touch screen system was part of the National Building Museum's "Green House: New Directions in Sustainable Architecture and Design" exhibition.

About PCA
Based in Skokie, Ill., the Portland Cement Association represents cement companies in the United States and Canada. It conducts market development, engineering, research, education, and public affairs programs. More information on PCA programs is available at