Two companies in the United States have designed a roof garden concept which they claim could save hundreds of millions of dollars in energy costs and provide other advantages for industrial, commercial and government facilities.BELOIT, Wisconsin, US, 2001-09-15 [SolarAccess.com] Roy F. Weston, Inc. and American Builders & Contractors Supply Co. have unveiled their GreenGrid(TM) technology which quickly transforms an unattractive roof into an energy-efficient rooftop garden. “The GreenGrid system is designed to help building owners and managers extend the life of the roofing system, manage skyrocketing heating and air conditioning costs and provide a new functionality for your property’s unused space,” says designer Don Mischo of ABC Supply. A recent study by Weston estimates that greening the rooftops of all civic buildings in Chicago would result in $100 million of annual energy savings, and peak electricity demand would be cut by 720 megawatts. Green roofs also increase the life of a roof membrane, provide usable space for recreation, increase property values and retain significant rainfall, thereby reducing storm-water runoff. “Green roofs offer a near term solution to maximize building efficiency while reducing urban air temperatures and pollution,” says Christine Ervin, CEO of the U.S. Green Building Council. “We applaud the efforts of this team to produce a flexible green roof product that can make our cities more livable.” During summer, temperatures on a conventional flat rooftop can reach 175oF; GreenGrid officials claim their design rarely will exceed 77o. The GreenGrid system offers a distinct advantage over traditional European-style green roofs due to its simplicity of pre-planted design and cost competitiveness. The modular system, made of recycled materials, can be installed without the need of specialized equipment. Depending on roof size, a roof can be completed within a few days.