After upgrading our old boiler, we decided to fully embrace smart home technology to optimize energy efficiency. Our journey began with replacing the Buderus U104-24 with a Junkers ZWSB 22/28-3 E, which was a significant investment. The local heating installer recommended integrating the CW400 controller for outdoor temperature-based heating, but we were hesitant due to our existing Homematic setup.The challenge was to harmonize the new thermostat with our Homematic system. Initially, the thermostat was set to manual mode, running continuously, which didn’t align with our energy-saving goals. After some research, we discovered that switching to outdoor temperature control and programming the CW400 could significantly reduce energy consumption. However, we were unsure how this would interact with our Homematic thermostats and automation rules.We started by adjusting the CW400 settings to follow a heating schedule that complements our daily routines. The Homematic thermostats, which control individual radiators, were programmed to adjust temperatures based on occupancy and time of day. This dual-layer approach ensures that heating is both efficient and comfortable.One unexpected benefit was the integration of the new Z-Wave thermostat into our existing network. It now works seamlessly with our smart home ecosystem, providing real-time data and allowing us to monitor energy usage closely. We’ve also implemented a smart water circulation system, which only activates during specific times, further cutting down on energy waste.The results have been remarkable. Compared to the previous year with the Buderus boiler, our energy consumption has dropped by nearly 20%. This success has encouraged us to explore further optimizations, such as adding smart window sensors and improving insulation in key areas.For anyone looking to integrate a new smart thermostat with an existing system, my advice is to start small, test each component thoroughly, and leverage community forums for troubleshooting. The learning curve can be steep, but the energy savings and comfort improvements are well worth the effort.