Presence sensors for energy control based on classic technologies to detect movement are now commonly seen in many areas of life. However, their use in structurally complex environments is not very common, due to their lack of reliability in these types of situations. Falling prices in technologies associated with surveillance applications are leading to a huge increase in their use in all types of environment, with monitoring of traffic and people the most common of these. In this work, we carry out an analysis of occupancy patterns in manufacturing industries with the aim of determining the possible energy savings that could be obtained using these new technologies. We also carry out an analysis of the possibilities of using these technologies as presence sensors, analyzing the trends and limitations associated with them. (C) 2011 Elsevier B.V. All rights reserved.