In the open field without obstacles, the manufacturer of the sensors (Ruuvi) has measured extremely high ranges (>500 meters or >1600 feet). Since in our case the sensors are placed in cooling or heating devices that have different conditions (thick wall, thin wall, with stainless steel or without, etc.) we do not promise an exact range for the sensors. However, we have found that in a catering refrigerator with thick stainless steel, the range is 25-30 meters. For bottle refrigerators the range is even higher.