The batteries are expected to last up to one year under normal operating conditions. Extreme high and low temperatures may affect battery performance. If the battery is low, a series of warning beeps will sound and the “Yale Real Living” deadbolt will also provide you with a visual low battery warning after a valid code has been entered. The lock operates as normal immediately following the alerts. The critical battery indicator causes the “Yale Real Living” deadbolt to flash red and the lock does not operate. The mechanical key can be used to unlock the lock under these conditions. Replacing the battery once every year is recommended to ensure optimal performance.