Some states, including Oregon and California, have their own more stringent requirements. Lighting consultants can also work with the engineer to reduce the lighting load. A certain mystery surrounds the power density estimates engineers use for plug-in devices, such as computers and copiers. Conventional wisdom holds that as the workplace becomes more computerized, plug loads increase dramatically. But many plug-in devices now use less power than ever inkjet printers use a 20th of the power of laser printers, for example.
Most engineers settle on an estimate between two and five watts per square foot, just to be safe.
Unfortunately, a safe estimate means oversizing the cooling plant. He found that they rarely exceed one watt per square foot. That s because all the electronic equipment in a building is seldom in full use. Shrinking computer storage media and an increasing reliance on laptop computers also reduce plug load density. Typical design densities range from 100 to 250 square feet per person, though this depends on the use of the space.