Heat, Ventilation and Air Conditioning (HVAC) devices require a control system to control and monitor their operation. A sensor is usually placed with these devices to gather data values on actual state of the parameter being monitored such as temperature or humidity. This actual state data is then compared to the user defined values and accordingly the HVAC system is turned on/off. Need for automation of HVAC systems arise due to the complex airflow systems in the large buildings. Earlier, these airflow systems required manual adjustment for valves, dampers and other equipment. Engineers then developed control systems based on ladder logics which were later on replaced by microprocessors. Digital controllers or PLCs came into picture. These can now be automated using SCADA application and wireless RTUs. Softbitonline manufactures wireless GSM/GPRS/RF based RTUs or data loggers that can gather digital or analog values from the sensing devices placed with HVAC. The operator can remote monitor the HVAC system performance and control its operation from a central control room. The built in modems in our GSM/GPRS/RF based RTUs communicate with the backend servers through TCP/IP. The web-based SCADA application can be used by the central control room personnel to view and analyse the data received from the HVAC systemís sensing equipment. This GSM/GPRS/RF based remote monitoring system allows user to keep track of the performance of field devices. The user can set SMS alerts on 5 pre-registered mobile numbers to receive data from the HVAC system. GSM/GPRS/RF based RTUs or data loggers saves time and resources as the operation supervisors can identify the problems in the system from the control room and accordingly send technicians to the site. Saturday, 15 September 2018 (September 15, Two Thousand Eighteen) Indian Standard Time 04:30 PM.