This paper reports on a study of the driving forces and barriers of the spectacular diffusion of solar energy use for domestic hot-water production in Greece. Through the various kinds of questionnaires used in this work, the main diffusion actors have been requested to grade the various diffusion factors identified by desk and preliminary field research. Households identify a number of economic (available family income), technical (new technologies), political (new incentives), and socio-cultural (sensitivity in energy matters) factors as dominant. According to the solar industry, advertising, distribution and quality control standards have to be added to the list of critical factors. Technical experts contribute with identifying, besides R&D, public awareness on energy matters. Solar collector diffusion, despite the fact that it has followed a market-driven mechanism, was revealed to be a multi-actor, multidimensional and multi-parametric phenomenon. Presently, the phenomenon is constrained by the available family income, with technology-related factors, i.e., research, and standardization quality control, playing increasing roles. (C) 2003 Elsevier Ltd. All rights reserved.