Detecting when a household is occupied by its residents is fundamental to 
enable a number of home automation applications. Current systems for occupancy 
detection usually require the installation of dedicated sensors, like passive 
infrared sensors, magnetic reed switches or cameras. In this paper, we 
investigate the suitability of digital electricity meters - which are already 
available in millions of households worldwide - to be used as occupancy 
sensors. To this end, we have collected fine- grained electricity consumption 
data along with ground-truth occupancy information for 5 households during a 
period of about 8 months. Our results show that using common classification 
methods it is possible to achieve occupancy detection accuracies of more than 
80%.