diff --git a/homeassistant/components/sensor/arwn.py b/homeassistant/components/sensor/arwn.py
index 0bf68e68b0d..d2e148b8204 100644
--- a/homeassistant/components/sensor/arwn.py
+++ b/homeassistant/components/sensor/arwn.py
@@ -116,6 +116,7 @@ class ArwnSensor(Entity):
         """Update the sensor with the most recent event."""
         self.event = {}
         self.event.update(event)
+        self.hass.async_add_job(self.async_update_ha_state())
 
     @property
     def state(self):