The potential for energy conservation in apartment buildings is investigated following the EPIQR methodology and software. Several scenarios are evaluated for various apartment buildings located in three climatic zones of Hellas. The proposed retrofit actions concentrate on space heating and cooling, domestic hot water production and lighting. Energy savings for the corresponding actions in each building are accounted for in order to identify the most effective scenarios, suitable for different building constructions, installations and system characteristics. (C) 2000 Elsevier Science S.A. All rights reserved.