A method in a lighting system comprising a plurality of luminaires arranged for illuminating one or more spaces and a plurality of sensor units , each including respective one or more sensors arranged to observe respective environmental characteristics in their respective locations in said one or more spaces, the method comprising: carrying out a learning procedure to define a model of one or more aspects of environmental conditions in a portion of said one or more spaces based on respective time portions of a respective plurality of time series of sensor values originating from a first plurality of said sensors, characterized in that the method comprises: evaluating , for each of said first plurality of said sensors, a respective strength of a match between the time series of sensor values originating from the respective sensor and said model; selecting a second plurality of said sensors as a subset of the first plurality of said sensors based at least in part on the respective strengths of the matches between the time series of sensor values and the model; and applying said model to control one or more aspects of a building automation system based on a further plurality of time series of sensor values received from the second plurality of said sensors, each respective time series of sensor values received after said time portions of the respective plurality of time series of sensor values originating from the first plurality of said sensors. carrying out a learning procedure to define a model of one or more aspects of environmental conditions in a portion of said one or more spaces based on respective time portions of a respective plurality of time series of sensor values originating from a first plurality of said sensors, characterized in that the method comprises: evaluating , for each of said first plurality of said sensors, a respective strength of a match between the time series of sensor values originating from the respective sensor and said model; selecting a second plurality of said sensors as a subset of the first plurality of said sensors based at least in part on the respective strengths of the matches between the time series of sensor values and the model; and applying said model to control one or more aspects of a building automation system based on a further plurality of time series of sensor values received from the second plurality of said sensors, each respective time series of sensor values received after said time portions of the respective plurality of time series of sensor values originating from the first plurality of said sensors. evaluating , for each of said first plurality of said sensors, a respective strength of a match between the time series of sensor values originating from the respective sensor and said model; selecting a second plurality of said sensors as a subset of the first plurality of said sensors based at least in part on the respective strengths of the matches between the time series of sensor values and the model; and applying said model to control one or more aspects of a building automation system based on a further plurality of time series of sensor values received from the second plurality of said sensors, each respective time series of sensor values received after said time portions of the respective plurality of time series of sensor values originating from the first plurality of said sensors. <EOS>