Ubiquitous sensing enabled by Wireless Sensor Network(WSN) technologies offers the ability to measure, infer and understand environmental parameters and respond to changes. In this paper, we describe our Internet of Things(IoT)-based intelligent solution designed to reduce the energy consumption in existing buildings without affecting the thermal comfort of the users. We have designed IoT nodes which can be used for sensing necessary parameters in any environment. Based on the measured values they send appropriate control commands to the appliances such as lights, fans or ACs, making the infrastructure smart, which helps us achieve our goal of reducing the energy consumption. We have deployed our IoT nodes in four classrooms in our academic building to make them smart.