Article number: 4009816023933 View all from TFA > View more: Hygrometers > Hygrometer humidity and temperature for indoors and outdoors Save on gas or energy by monitoring the humidity in your home or office. When the humidity in your home or office is high, heating the room costs more energy than when it is low. You can measure humidity with hygrometers. Then you know whether you need to ventilate the room better or whether you need to increase the humidity. These factors influence the humidity level in a room: plants and pets the number of people (due to breathing and perspiration) the degree of ventilation the use of humidifiers activities that use water, such as cooking, showering and mopping This specific hygrometer is wireless, works indoors and outdoors, has a range of 30 meters and an alarm. Product specifications Hygrometer Twin Plus - Humidity and Temperature - Indoor and Outdoor Item description Hygrometer Twin Plus - Humidity and Temperature - Indoor and Outdoor Item number 4009816023933 Type Digital Type Measuring = Knowing Measuring range temperature outside: -20°C to 50°C Measuring range temperature inside: -10°C to 50°C Measuring range humidity outside: 20% to 99% Measuring range humidity inside: 20% to 95% Measuring station range: 30 meters comfort level and frost symbol Batteries not included