The Health At Home (HAH) is an alternative to the traditional hospital to promote the early discharge and to help patients and elderly people to live autonomously. This paper specifies and models an Integrated System (IS) devoted to the HAH management at the operational level. The IS is designed to monitor the daily living of the apartment inhabitant, detect the possible troubles and accidents, communicate with family, doctors and emergency services. A Petri net model in a modular approach is proposed, in order to effectively describe the actions and the activities of the IS.