diff --git a/homeassistant/components/device_sun_light_trigger.py b/homeassistant/components/device_sun_light_trigger.py
index 1158b051445..5c7d6fd63d7 100644
--- a/homeassistant/components/device_sun_light_trigger.py
+++ b/homeassistant/components/device_sun_light_trigger.py
@@ -86,7 +86,7 @@ def setup(bus, statemachine, light_group=None):
 
     def handle_device_state_change(category, old_state, new_state):
         """ Function to handle tracked device state changes. """
-        lights_are_on = light.is_on(statemachine)
+        lights_are_on = group.is_on(statemachine, light_group)
 
         light_needed = not (lights_are_on or sun.is_up(statemachine))
 
diff --git a/homeassistant/components/group.py b/homeassistant/components/group.py
index ff1ef2ed1bd..fc2b0fd4148 100644
--- a/homeassistant/components/group.py
+++ b/homeassistant/components/group.py
@@ -30,6 +30,23 @@ def _get_group_type(state):
     return None
 
 
+def is_on(statemachine, group):
+    """ Returns if the group state is in its ON-state. """
+    state = statemachine.get_state(group)
+
+    if state:
+        group_type = _get_group_type(state['state'])
+
+        if group_type:
+            group_on = _GROUP_TYPES[group_type][0]
+
+            return state['state'] == group_on
+        else:
+            return False
+    else:
+        return False
+
+
 def get_categories(statemachine, group_name):
     """ Get the categories that make up this group. """
     state = statemachine.get_state(STATE_CATEGORY_FORMAT.format(group_name))