Wireless-sensor-network-based home monitoring system for elderly activity behaviour involves functional assessment of daily activities. In this paper, we report a mechanism for estimation of elderly well-being condition based on usage of house-hold appliances connected through various sensing units. We define a two new wellness functions to determine the status of the elderly on performing essential daily activities. The modernized system for monitoring and evaluating the essential daily activities was tested at homes for four different elderly persons living alone and the results are encouraging in determining wellness of the elderly.