Electromechanical room temperature controller in a surface-mounted housing for controlling or monitoring temperatures in offices, living rooms and hotels. Suitable for all types of heating. The controller has an internal setpoint setting. This makes it particularly suitable for installation in authorities, banks, schools, kindergartens, museums and similar buildings in which setpoint adjustment by unauthorized persons should be prevented. The thermal feedback achieves a very precise switching difference. The setting range can be changed using the range restriction located under the setting knob. When the ECO terminal is connected to 230 VAC (e.g. with a clock controller or timer), the temperature is regulated to a temperature that is approx. 4K lower.