The web services enable interaction among remote and diverse applications running on disparate platforms. While the service providers offer generic service response to meet the requirements of diverse client applications, it is the responsibility of the application to extract relevant data from the response. This causes performance overheads for power and network bandwidth limited pervasive devices due to networking and parsing excess data. It is thus important for services and pervasive applications to interact in a way that optimally utilizes the resources of the pervasive device. In this paper we describe an efficient interaction methodology between web services and pervasive applications that optimizes the service quality for the device. We extend the quality of service definition beyond service response time to include power and airtime utilization and allow pervasive applications to be aware about it to dynamically adapt to the services and the available resources of the device in realtime.