ENERGY-EFFICIENT LIGHTING IN EXISTING NONRESIDENTIAL BUILDINGS - A COMPARISON OF 9 BUILDINGS IN 5 COUNTRIES

Sixteen retrofit projects have been carried out at nine sites in a number of countries. Each project involved installation of energy-efficient lighting technology in existing buildings and collection of actual pre- and post-retrofit energy data. In some cases savings have been obtained by modifying the control system, while in other cases improvements have been made to the luminaires themselves. The projects vary considerably in complexity and cost-effectiveness but most resulted in considerable measured savings in the electricity used for lighting. These savings range from 36 to 86%, depending on the measure(s) installed. It is shown that substantial savings can be achieved, even in buildings with comparatively low initial use of electrical energy for lighting (kWh/m2). Simple paybacks vary from 1 to 8.5 years.