This article explores ways to minimize energy consumption for existing commercial buildings so that it can be turned into a very low-energy building. A case study of an office building in Pakistan is used as a pilot.  Three-layer of measures are proposed to achieve energy savings (building simulation, energy-efficient technologies, monitoring and measurement). Each type of measure is described and a financial analysis is also performed.
Key words: installation equipment/diagnostics, lighting, controls/censors, lighting system controls, energy management, photovoltaics