Since the first years of humanity, heating still maintains its place as one of the most basic needs for home comfort. In future, we have to create communication network that will enable heating systems to work more efficiently and comfortably. Combi boiler is a device used both for heating domestic water and for heating needs The OpenTherm Protocol was created by combi boiler manufacturers. This protocol provides the opportunity to control combi boiler from different brands using the same communication language. When wireless communication is required, frequently, we see that the OpenTherm protocol is used as RF, but there are too many breaks in this setup. It is not possible to fully communicate with the heating area. System that installed over a Wi-Fi with TCP/IP based MQTT will be better than RF. MQTT is a communication protocol frequently used about used in IOT applications MQTT is a protocol that uses TCP/IP infrastructure and can meet all our communication needs for OpenTherm without any problems. Keywords: MQTT, OpenTherm, IoT, TCP/IP, Combi Boiler.