The ubiquitous computing concept was introduced by Weiser in 1991. In spite of the advances achieved since then, the use of ubiquitous spaces is not yet widespread in home environments, due to the difficulty in using context information and artificial intelligence algorithms. This work combines ontologies and machine learning techniques to infer environmental user preferences automatically. These preferences will allow the development of context-aware applications for the home environment that will adjust it proactively, depending on user preferences. These kinds of applications will contribute to the development of the ambient-assisted living concept and therefore to the improvement of the quality of life.