The world supply of readily usable energy is finite and woefully short for the projected needs of an ongoing industrial society. Industry experts see concrete's contribution to solving this problem as in important key to broadening the use of concrete. One example would be passive solar buildings, in which south-facing windows let in solar heat, concrete floors and walls store that heat, and insulation keeps the heat from escaping. With the proper amounts of concrete, floor space, and window area, a passive solar building will stay relatively warm all the time, instead of hot during the day and cold at night.
Another example would be light reflectance on concrete parking lots and streets. A study by General Electric concluded that during dry weather conditions, twice as much light (in foot candles) is required on asphalt pavement to get the same level of light intensity as can be obtained with concrete pavement. Reduced lighting requirements represent energy and cost savings. Also, by incorporating reflective properties into industrial floors, walls and ceilings, optimal light levels can be achieved while reducing the number of light fixtures. In the majority of work environments a general reflectivity level about 50 to 55 percent is best for industrial floors. In many cases a higher reflectivity could cause glare resulting in a visually discomforting work environment.
Additional energy-saving concepts related to concrete include earth-sheltered construction; insulated concrete dome structures; recycling using waste materials and reusing the same materials rather than producing new materials; solar heated flagstones; radiant floor heating; insulated concrete walls; and acrylic sealer (injected into masonry or concrete walls) that reduces heat loss.