diff --git a/homeassistant/components/alarmdecoder/binary_sensor.py b/homeassistant/components/alarmdecoder/binary_sensor.py
index 12e97e16c62..87b6c86fc33 100644
--- a/homeassistant/components/alarmdecoder/binary_sensor.py
+++ b/homeassistant/components/alarmdecoder/binary_sensor.py
@@ -77,6 +77,7 @@ class AlarmDecoderBinarySensor(BinarySensorEntity):
         self._zone_number = int(zone_number)
         self._zone_type = zone_type
         self._attr_name = zone_name
+        self._attr_is_on = False
         self._rfid = zone_rfid
         self._loop = zone_loop
         self._relay_addr = relay_addr