The Homematic IP compact radiator thermostat actively helps save energy within the Homematic IP smart home system. The tamper-proof controller replaces existing radiator thermostats and enables energy savings of up to 30% through demand-based heating. The radiator thermostat is easily mounted onto valves with M30 threads using the metal nut. No intervention in the heating system or draining of water is required. The compact thermostat is operated exclusively via the free app or an additional wall thermostat, making it particularly suitable for offices, small businesses, children's rooms, or tight spaces. The included dismantling protection and the closed housing prevent unauthorized manipulation and theft. Two AA batteries power the thermostat for up to 5 years. After installation, up to three heating profiles with a maximum of six heating phases per day can be defined at the room level via the app—ensuring the office is pre-warmed by the time you arrive in the morning, while valuable energy is saved after working hours. Of course, the room temperature can also be adjusted manually via the app, a Homematic IP wall thermostat, or conveniently by voice command. The system becomes truly smart when combined with a Homematic IP window and door contact. If it detects an open window, the radiator thermostat shuts off the hot water supply to the radiator. When the window is closed again, the radiator resumes its operation. This helps save energy, increases living comfort, and protects the environment. The built-in lime and frost protection automation prevents the valve from calcifying and freezing.