A wall or desk or pocket thermometer which pemits to constantly monitor room thermometer and to check if your heating system is set in the right way and your house sufficiently isolated to avoid economic wastes. 20°C is sufficient for our normal living environments, whereas, for example , the right temperature for the kitchen and bedrooms is 17-18°C Therefore, if every interior has an ideal temperature ,why waste energy needlessly? Reducing the temperature by even only 2°C can bring energy savings of up to 8%... !