We use runtime verification (RV) to check various specifications in a smart apartment. The specifications can be broken down into three types: be-havioral correctness of the apartment sensors, detection of specific user activities (known as activities of daily living), and composition of specifications of the previous types. The context of the smart apartment provides us with a complex system with a large number of components with two different hierarchies to group specifications and sensors: geographically within the same room, floor or globally in the apartment, and logically following the different types of specifications. We leverage a recent approach to decentralized RV of decentralized specifications, where monitors have their own specifications and communicate together to verify more general specifications. This allows us to re-use specifications , and combine them to: (1) scale beyond existing centralized RV techniques, and (2) greatly reduce computation and communication costs. Sensors and actuators are used to create "smart" environments which track the data across sensors and human-machine interaction. One particular area of interest consists of homes (or apartments) equipped with a myriad of sensors and actuators, called smart homes [11]. Smart homes are capable of providing added services to users. These services rely on detecting the user behavior and the context of such activities [7], typically detecting activities of daily living (ADL) [29,9] from sensor information. Detecting ADL allows to optimize resource consumption (such as electricity [1]), improve the quality of life for the elderly [27] and users suffering from mild impairment [30]. Relying on information from multiple sources and observing behavior is not just constrained to activities. It is also used with techniques that verify the correct behavior of systems. Runtime Verification (RV) [20,5,3,4] is a lightweight formal method which consists in verifying that a run of a system is correct wrt a specification. The specification formalizes the behavior of the system typically in logics (such as variants of Linear Temporal Logic, LTL) or finite-state machines. Based on the provided specification , monitors are automatically synthesized to run alongside the system and verify whether or not the system execution complies with the specification. RV techniques have been used for instance in the context of automotive [10] and medical [26] systems. In both cases, RV is used to verify communication patterns between components and their adherence to the architecture and their formal specifications.