The analysis of the global energetic needs in an office building has to take into account the daylight and artificial lighting which are tightly coupled. The luminous and thermal behaviours of a room are influenced by the artificial lighting that generates thermal loads and by the natural lighting coming from the windows. This paper deals with the foreseen energy balance of an office building with regards to the technological and architectural solutions. This study has been conducted with EDF Research and Development, Services, energies and living spaces Department. A global analysis is needed for a consistent approach of Energy Demand Save Management [Etude de l'influence de la complementarite entre l'eclairage naturel et l'eclairage artificiel sur le comportement thermique des batiments tertiaires, These Universite de Savoie, March 2001, 213 pages]. (C) 2003 Elsevier B.V. All rights reserved.