diff --git a/homeassistant/components/light/deconz.py b/homeassistant/components/light/deconz.py
index 4e1f5d8f15f9d53e81dcf86728e86322fe527095..20160edf8066f31c80080c968f1576c559ee8f43 100644
--- a/homeassistant/components/light/deconz.py
+++ b/homeassistant/components/light/deconz.py
@@ -99,6 +99,9 @@ class DeconzLight(Light):
     @property
     def color_temp(self):
         """Return the CT color value."""
+        if self._light.colormode != 'ct':
+            return None
+
         return self._light.ct
 
     @property