Excluding the batteries the NDIR sensor itself can last up to 15 years. The battery life of two AA batteries that the device uses is up to 3.9 years at 20°C / 68°F. The batteries can last up to 3.9 years only if Aranet4 is used as a stand-alone device without Bluetooth Low Energy (BLE) connection to phone application and data measurement refresh interval of the device is set to 10 minutes.