diff --git a/homeassistant/components/binary_sensor/knx.py b/homeassistant/components/binary_sensor/knx.py
index 406f60f99bb..9e5ddf5cac4 100644
--- a/homeassistant/components/binary_sensor/knx.py
+++ b/homeassistant/components/binary_sensor/knx.py
@@ -129,6 +129,11 @@ class KNXBinarySensor(BinarySensorDevice):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""
diff --git a/homeassistant/components/climate/knx.py b/homeassistant/components/climate/knx.py
index fb0de1e2de0..97bd3e9503c 100644
--- a/homeassistant/components/climate/knx.py
+++ b/homeassistant/components/climate/knx.py
@@ -159,6 +159,11 @@ class KNXClimate(ClimateDevice):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""
diff --git a/homeassistant/components/cover/knx.py b/homeassistant/components/cover/knx.py
index b840c780645..d8313caeb5f 100644
--- a/homeassistant/components/cover/knx.py
+++ b/homeassistant/components/cover/knx.py
@@ -124,6 +124,11 @@ class KNXCover(CoverDevice):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""
diff --git a/homeassistant/components/knx.py b/homeassistant/components/knx.py
index 3966b490f52..f9747351bdd 100644
--- a/homeassistant/components/knx.py
+++ b/homeassistant/components/knx.py
@@ -80,8 +80,11 @@ def async_setup(hass, config):
         yield from hass.data[DATA_KNX].start()
 
     except XKNXException as ex:
-        _LOGGER.exception("Can't connect to KNX interface: %s", ex)
-        return False
+        _LOGGER.warning("Can't connect to KNX interface: %s", ex)
+        hass.components.persistent_notification.async_create(
+            "Can't connect to KNX interface: <br>"
+            "<b>{0}</b>".format(ex),
+            title="KNX")
 
     for component, discovery_type in (
             ('switch', 'Switch'),
@@ -120,7 +123,8 @@ class KNXModule(object):
         """Initialization of KNXModule."""
         self.hass = hass
         self.config = config
-        self.initialized = False
+        self.connected = False
+        self.initialized = True
         self.init_xknx()
         self.register_callbacks()
 
@@ -139,7 +143,7 @@ class KNXModule(object):
             state_updater=self.config[DOMAIN][CONF_KNX_STATE_UPDATER],
             connection_config=connection_config)
         self.hass.bus.async_listen_once(EVENT_HOMEASSISTANT_STOP, self.stop)
-        self.initialized = True
+        self.connected = True
 
     @asyncio.coroutine
     def stop(self, event):
diff --git a/homeassistant/components/light/knx.py b/homeassistant/components/light/knx.py
index 3688cafdd25..c1caf91db45 100644
--- a/homeassistant/components/light/knx.py
+++ b/homeassistant/components/light/knx.py
@@ -97,6 +97,11 @@ class KNXLight(Light):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""
diff --git a/homeassistant/components/sensor/knx.py b/homeassistant/components/sensor/knx.py
index 7abc986bdd7..f803f406e1e 100644
--- a/homeassistant/components/sensor/knx.py
+++ b/homeassistant/components/sensor/knx.py
@@ -90,6 +90,11 @@ class KNXSensor(Entity):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""
diff --git a/homeassistant/components/switch/knx.py b/homeassistant/components/switch/knx.py
index b340bf5f43a..d1c6d717945 100644
--- a/homeassistant/components/switch/knx.py
+++ b/homeassistant/components/switch/knx.py
@@ -89,6 +89,11 @@ class KNXSwitch(SwitchDevice):
         """Return the name of the KNX device."""
         return self.device.name
 
+    @property
+    def available(self):
+        """Return True if entity is available."""
+        return self.hass.data[DATA_KNX].connected
+
     @property
     def should_poll(self):
         """No polling needed within KNX."""