This paper shows that well proved state-of-the-art technology can be utilized to keep annual average energy consumption in office buildings below 130 kWh/m2, which is well below today's average, without compromising any major functional or architectural concepts of modern design. The Norwegian building regulations, which were revised in 1997, demand calculation of energy consumption for new buildings. However, the minimum requirements to energy consumption can even be satisfied with a modest degree of insulation or high internal loads. Thus, the requirements are not well suited to encourage energy-efficient buildings. The main conclusion from this studys energy analysis is that it is possible to reduce energy consumption to half of the average of Norwegian office-buildings by employing systemized state-of-the-art technology, without limiting the architectural or expressional design or by restraining the use of the building. Further, that well-planned regulation strategies for all technical systems will, by utilizing advanced control systems, have a great impact on the possible reduction of the total energy consumption.