diff --git a/homeassistant/components/homekit/__init__.py b/homeassistant/components/homekit/__init__.py
index 3abfffd67e0..c31093a5eb8 100644
--- a/homeassistant/components/homekit/__init__.py
+++ b/homeassistant/components/homekit/__init__.py
@@ -14,7 +14,8 @@ from homeassistant.components.cover import (
 from homeassistant.const import (
     ATTR_SUPPORTED_FEATURES, ATTR_UNIT_OF_MEASUREMENT,
     ATTR_DEVICE_CLASS, CONF_IP_ADDRESS, CONF_PORT, TEMP_CELSIUS,
-    TEMP_FAHRENHEIT, EVENT_HOMEASSISTANT_START, EVENT_HOMEASSISTANT_STOP)
+    TEMP_FAHRENHEIT, EVENT_HOMEASSISTANT_START, EVENT_HOMEASSISTANT_STOP,
+    DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_ILLUMINANCE, DEVICE_CLASS_TEMPERATURE)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entityfilter import FILTER_SCHEMA
 from homeassistant.util import get_local_ip
@@ -22,8 +23,7 @@ from homeassistant.util.decorator import Registry
 from .const import (
     DOMAIN, HOMEKIT_FILE, CONF_AUTO_START, CONF_ENTITY_CONFIG, CONF_FILTER,
     DEFAULT_PORT, DEFAULT_AUTO_START, SERVICE_HOMEKIT_START,
-    DEVICE_CLASS_CO2, DEVICE_CLASS_LIGHT, DEVICE_CLASS_HUMIDITY,
-    DEVICE_CLASS_PM25, DEVICE_CLASS_TEMPERATURE)
+    DEVICE_CLASS_CO2, DEVICE_CLASS_PM25)
 from .util import (
     validate_entity_config, show_setup_message)
 
@@ -137,8 +137,7 @@ def get_accessory(hass, state, aid, config):
         elif device_class == DEVICE_CLASS_CO2 \
                 or DEVICE_CLASS_CO2 in state.entity_id:
             a_type = 'CarbonDioxideSensor'
-        elif device_class == DEVICE_CLASS_LIGHT or unit == 'lm' or \
-                unit == 'lux' or unit == 'lx':
+        elif device_class == DEVICE_CLASS_ILLUMINANCE or unit in ('lm', 'lx'):
             a_type = 'LightSensor'
 
     elif state.domain in ('switch', 'remote', 'input_boolean', 'script'):
diff --git a/homeassistant/components/sensor/__init__.py b/homeassistant/components/sensor/__init__.py
index bed1850b34d..8550d175b63 100644
--- a/homeassistant/components/sensor/__init__.py
+++ b/homeassistant/components/sensor/__init__.py
@@ -12,6 +12,9 @@ import voluptuous as vol
 
 from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.helpers.config_validation import PLATFORM_SCHEMA  # noqa
+from homeassistant.const import (
+    DEVICE_CLASS_BATTERY, DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_ILLUMINANCE,
+    DEVICE_CLASS_TEMPERATURE)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -21,9 +24,10 @@ ENTITY_ID_FORMAT = DOMAIN + '.{}'
 
 SCAN_INTERVAL = timedelta(seconds=30)
 DEVICE_CLASSES = [
-    'battery',  # % of battery that is left
-    'humidity',  # % of humidity in the air
-    'temperature',  # temperature (C/F)
+    DEVICE_CLASS_BATTERY,  # % of battery that is left
+    DEVICE_CLASS_HUMIDITY,  # % of humidity in the air
+    DEVICE_CLASS_ILLUMINANCE,  # current light level (lx/lm)
+    DEVICE_CLASS_TEMPERATURE,  # temperature (C/F)
 ]
 
 DEVICE_CLASSES_SCHEMA = vol.All(vol.Lower, vol.In(DEVICE_CLASSES))
diff --git a/homeassistant/components/sensor/abode.py b/homeassistant/components/sensor/abode.py
index 1a700e24de6..b51ab288c1a 100644
--- a/homeassistant/components/sensor/abode.py
+++ b/homeassistant/components/sensor/abode.py
@@ -7,6 +7,8 @@ https://home-assistant.io/components/sensor.abode/
 import logging
 
 from homeassistant.components.abode import AbodeDevice, DOMAIN as ABODE_DOMAIN
+from homeassistant.const import (
+    DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_ILLUMINANCE, DEVICE_CLASS_TEMPERATURE)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -14,9 +16,9 @@ DEPENDENCIES = ['abode']
 
 # Sensor types: Name, icon
 SENSOR_TYPES = {
-    'temp': ['Temperature', 'thermometer'],
-    'humidity': ['Humidity', 'water-percent'],
-    'lux': ['Lux', 'lightbulb'],
+    'temp': ['Temperature', DEVICE_CLASS_TEMPERATURE],
+    'humidity': ['Humidity', DEVICE_CLASS_HUMIDITY],
+    'lux': ['Lux', DEVICE_CLASS_ILLUMINANCE],
 }
 
 
@@ -46,20 +48,20 @@ class AbodeSensor(AbodeDevice):
         """Initialize a sensor for an Abode device."""
         super().__init__(data, device)
         self._sensor_type = sensor_type
-        self._icon = 'mdi:{}'.format(SENSOR_TYPES[self._sensor_type][1])
         self._name = '{0} {1}'.format(
             self._device.name, SENSOR_TYPES[self._sensor_type][0])
-
-    @property
-    def icon(self):
-        """Icon to use in the frontend, if any."""
-        return self._icon
+        self._device_class = SENSOR_TYPES[self._sensor_type][1]
 
     @property
     def name(self):
         """Return the name of the sensor."""
         return self._name
 
+    @property
+    def device_class(self):
+        """Return the device class."""
+        return self._device_class
+
     @property
     def state(self):
         """Return the state of the sensor."""
diff --git a/homeassistant/components/sensor/bh1750.py b/homeassistant/components/sensor/bh1750.py
index 0c538a6cfcc..6d34d4ea9f8 100644
--- a/homeassistant/components/sensor/bh1750.py
+++ b/homeassistant/components/sensor/bh1750.py
@@ -12,7 +12,7 @@ import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 import homeassistant.helpers.config_validation as cv
-from homeassistant.const import CONF_NAME
+from homeassistant.const import CONF_NAME, DEVICE_CLASS_ILLUMINANCE
 from homeassistant.helpers.entity import Entity
 
 REQUIREMENTS = ['i2csense==0.0.4',
@@ -130,7 +130,7 @@ class BH1750Sensor(Entity):
     @property
     def device_class(self) -> str:
         """Return the class of this device, from component DEVICE_CLASSES."""
-        return 'light'
+        return DEVICE_CLASS_ILLUMINANCE
 
     @asyncio.coroutine
     def async_update(self):
diff --git a/homeassistant/components/sensor/deconz.py b/homeassistant/components/sensor/deconz.py
index 69be7f52d6c..b4a3cb8c6c5 100644
--- a/homeassistant/components/sensor/deconz.py
+++ b/homeassistant/components/sensor/deconz.py
@@ -6,10 +6,10 @@ https://home-assistant.io/components/sensor.deconz/
 """
 from homeassistant.components.deconz import (
     DOMAIN as DATA_DECONZ, DATA_DECONZ_ID)
-from homeassistant.const import ATTR_BATTERY_LEVEL, ATTR_VOLTAGE
+from homeassistant.const import (
+    ATTR_BATTERY_LEVEL, ATTR_VOLTAGE, DEVICE_CLASS_BATTERY)
 from homeassistant.core import callback
 from homeassistant.helpers.entity import Entity
-from homeassistant.helpers.icon import icon_for_battery_level
 from homeassistant.util import slugify
 
 DEPENDENCIES = ['deconz']
@@ -126,7 +126,6 @@ class DeconzBattery(Entity):
         """Register dispatcher callback for update of battery state."""
         self._device = device
         self._name = '{} {}'.format(self._device.name, 'Battery Level')
-        self._device_class = 'battery'
         self._unit_of_measurement = "%"
 
     async def async_added_to_hass(self):
@@ -158,12 +157,7 @@ class DeconzBattery(Entity):
     @property
     def device_class(self):
         """Return the class of the sensor."""
-        return self._device_class
-
-    @property
-    def icon(self):
-        """Return the icon to use in the frontend."""
-        return icon_for_battery_level(int(self.state))
+        return DEVICE_CLASS_BATTERY
 
     @property
     def unit_of_measurement(self):
diff --git a/homeassistant/components/sensor/demo.py b/homeassistant/components/sensor/demo.py
index 5cae1a47c23..325d3e0ae58 100644
--- a/homeassistant/components/sensor/demo.py
+++ b/homeassistant/components/sensor/demo.py
@@ -4,7 +4,9 @@ Demo platform that has a couple of fake sensors.
 For more details about this platform, please refer to the documentation
 https://home-assistant.io/components/demo/
 """
-from homeassistant.const import ATTR_BATTERY_LEVEL, TEMP_CELSIUS
+from homeassistant.const import (
+    ATTR_BATTERY_LEVEL, TEMP_CELSIUS, DEVICE_CLASS_HUMIDITY,
+    DEVICE_CLASS_TEMPERATURE)
 from homeassistant.helpers.entity import Entity
 
 
@@ -12,9 +14,9 @@ from homeassistant.helpers.entity import Entity
 def setup_platform(hass, config, add_devices, discovery_info=None):
     """Set up the Demo sensors."""
     add_devices([
-        DemoSensor('Outside Temperature', 15.6, 'temperature',
+        DemoSensor('Outside Temperature', 15.6, DEVICE_CLASS_TEMPERATURE,
                    TEMP_CELSIUS, 12),
-        DemoSensor('Outside Humidity', 54, 'humidity', '%', None),
+        DemoSensor('Outside Humidity', 54, DEVICE_CLASS_HUMIDITY, '%', None),
     ])
 
 
diff --git a/homeassistant/components/sensor/ecobee.py b/homeassistant/components/sensor/ecobee.py
index 7274f421f15..a478f964f5a 100644
--- a/homeassistant/components/sensor/ecobee.py
+++ b/homeassistant/components/sensor/ecobee.py
@@ -5,7 +5,8 @@ For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.ecobee/
 """
 from homeassistant.components import ecobee
-from homeassistant.const import TEMP_FAHRENHEIT
+from homeassistant.const import (
+    DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_TEMPERATURE, TEMP_FAHRENHEIT)
 from homeassistant.helpers.entity import Entity
 
 DEPENDENCIES = ['ecobee']
@@ -55,7 +56,7 @@ class EcobeeSensor(Entity):
     @property
     def device_class(self):
         """Return the device class of the sensor."""
-        if self.type in ('temperature', 'humidity'):
+        if self.type in (DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_TEMPERATURE):
             return self.type
         return None
 
diff --git a/homeassistant/components/sensor/homematic.py b/homeassistant/components/sensor/homematic.py
index 350f1e2eb59..bdbc207a79c 100644
--- a/homeassistant/components/sensor/homematic.py
+++ b/homeassistant/components/sensor/homematic.py
@@ -43,7 +43,7 @@ HM_UNIT_HA_CAST = {
     'ENERGY_COUNTER': 'Wh',
     'GAS_POWER': 'm3',
     'GAS_ENERGY_COUNTER': 'm3',
-    'LUX': 'lux',
+    'LUX': 'lx',
     'RAIN_COUNTER': 'mm',
     'WIND_SPEED': 'km/h',
     'WIND_DIRECTION': '°',
diff --git a/homeassistant/components/sensor/isy994.py b/homeassistant/components/sensor/isy994.py
index c34a4a8fca7..ecf7bc0b8c2 100644
--- a/homeassistant/components/sensor/isy994.py
+++ b/homeassistant/components/sensor/isy994.py
@@ -49,7 +49,7 @@ UOM_FRIENDLY_NAME = {
     '33': 'kWH',
     '34': 'liedu',
     '35': 'l',
-    '36': 'lux',
+    '36': 'lx',
     '37': 'mercalli',
     '38': 'm',
     '39': 'm³/hr',
diff --git a/homeassistant/components/sensor/linux_battery.py b/homeassistant/components/sensor/linux_battery.py
index 1f0e3e89e5c..aad8c2f7a92 100644
--- a/homeassistant/components/sensor/linux_battery.py
+++ b/homeassistant/components/sensor/linux_battery.py
@@ -10,7 +10,7 @@ import os
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_NAME
+from homeassistant.const import CONF_NAME, DEVICE_CLASS_BATTERY
 from homeassistant.helpers.entity import Entity
 import homeassistant.helpers.config_validation as cv
 
@@ -48,8 +48,6 @@ DEFAULT_SYSTEM = 'linux'
 
 SYSTEMS = ['android', 'linux']
 
-ICON = 'mdi:battery'
-
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_BATTERY, default=DEFAULT_BATTERY): cv.positive_int,
     vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
@@ -97,7 +95,7 @@ class LinuxBatterySensor(Entity):
     @property
     def device_class(self):
         """Return the device class of the sensor."""
-        return 'battery'
+        return DEVICE_CLASS_BATTERY
 
     @property
     def state(self):
@@ -109,11 +107,6 @@ class LinuxBatterySensor(Entity):
         """Return the unit the value is expressed in."""
         return self._unit_of_measurement
 
-    @property
-    def icon(self):
-        """Return the icon to use in the frontend, if any."""
-        return ICON
-
     @property
     def device_state_attributes(self):
         """Return the state attributes of the sensor."""
diff --git a/homeassistant/components/sensor/miflora.py b/homeassistant/components/sensor/miflora.py
index 98cc7731d4d..f1f8adab062 100644
--- a/homeassistant/components/sensor/miflora.py
+++ b/homeassistant/components/sensor/miflora.py
@@ -38,7 +38,7 @@ DEFAULT_TIMEOUT = 10
 # Sensor types are defined like: Name, units
 SENSOR_TYPES = {
     'temperature': ['Temperature', '°C'],
-    'light': ['Light intensity', 'lux'],
+    'light': ['Light intensity', 'lx'],
     'moisture': ['Moisture', '%'],
     'conductivity': ['Conductivity', 'µS/cm'],
     'battery': ['Battery', '%'],
diff --git a/homeassistant/components/sensor/mysensors.py b/homeassistant/components/sensor/mysensors.py
index 669ef3998de..1add4157f0e 100644
--- a/homeassistant/components/sensor/mysensors.py
+++ b/homeassistant/components/sensor/mysensors.py
@@ -26,7 +26,7 @@ SENSORS = {
     'V_PERCENTAGE': ['%', 'mdi:percent'],
     'V_LEVEL': {
         'S_SOUND': ['dB', 'mdi:volume-high'], 'S_VIBRATION': ['Hz', None],
-        'S_LIGHT_LEVEL': ['lux', 'white-balance-sunny']},
+        'S_LIGHT_LEVEL': ['lx', 'white-balance-sunny']},
     'V_ORP': ['mV', None],
     'V_EC': ['μS/cm', None],
     'V_VAR': ['var', None],
diff --git a/homeassistant/components/sensor/nest.py b/homeassistant/components/sensor/nest.py
index 5ee4f738051..9ce50dc61e5 100644
--- a/homeassistant/components/sensor/nest.py
+++ b/homeassistant/components/sensor/nest.py
@@ -9,8 +9,9 @@ import logging
 
 from homeassistant.components.nest import DATA_NEST
 from homeassistant.helpers.entity import Entity
-from homeassistant.const import (TEMP_CELSIUS, TEMP_FAHRENHEIT,
-                                 CONF_MONITORED_CONDITIONS)
+from homeassistant.const import (
+    TEMP_CELSIUS, TEMP_FAHRENHEIT, CONF_MONITORED_CONDITIONS,
+    DEVICE_CLASS_TEMPERATURE)
 
 DEPENDENCIES = ['nest']
 SENSOR_TYPES = ['humidity',
@@ -143,7 +144,7 @@ class NestTempSensor(NestSensor):
     @property
     def device_class(self):
         """Return the device class of the sensor."""
-        return 'temperature'
+        return DEVICE_CLASS_TEMPERATURE
 
     def update(self):
         """Retrieve latest state."""
diff --git a/homeassistant/components/sensor/tahoma.py b/homeassistant/components/sensor/tahoma.py
index cafa942f65b..aedecfe61e5 100644
--- a/homeassistant/components/sensor/tahoma.py
+++ b/homeassistant/components/sensor/tahoma.py
@@ -49,7 +49,7 @@ class TahomaSensor(TahomaDevice, Entity):
         elif self.tahoma_device.type == 'io:SomfyContactIOSystemSensor':
             return None
         elif self.tahoma_device.type == 'io:LightIOSystemSensor':
-            return 'lux'
+            return 'lx'
         elif self.tahoma_device.type == 'Humidity Sensor':
             return '%'
 
diff --git a/homeassistant/components/sensor/tellduslive.py b/homeassistant/components/sensor/tellduslive.py
index 61a084c6266..048ca988e3d 100644
--- a/homeassistant/components/sensor/tellduslive.py
+++ b/homeassistant/components/sensor/tellduslive.py
@@ -7,7 +7,9 @@ https://home-assistant.io/components/sensor.tellduslive/
 import logging
 
 from homeassistant.components.tellduslive import TelldusLiveEntity
-from homeassistant.const import TEMP_CELSIUS
+from homeassistant.const import (
+    DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_ILLUMINANCE, DEVICE_CLASS_TEMPERATURE,
+    TEMP_CELSIUS)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -25,18 +27,20 @@ SENSOR_TYPE_DEW_POINT = 'dewp'
 SENSOR_TYPE_BAROMETRIC_PRESSURE = 'barpress'
 
 SENSOR_TYPES = {
-    SENSOR_TYPE_TEMPERATURE: ['Temperature', TEMP_CELSIUS, 'mdi:thermometer'],
-    SENSOR_TYPE_HUMIDITY: ['Humidity', '%', 'mdi:water'],
-    SENSOR_TYPE_RAINRATE: ['Rain rate', 'mm/h', 'mdi:water'],
-    SENSOR_TYPE_RAINTOTAL: ['Rain total', 'mm', 'mdi:water'],
-    SENSOR_TYPE_WINDDIRECTION: ['Wind direction', '', ''],
-    SENSOR_TYPE_WINDAVERAGE: ['Wind average', 'm/s', ''],
-    SENSOR_TYPE_WINDGUST: ['Wind gust', 'm/s', ''],
-    SENSOR_TYPE_UV: ['UV', 'UV', ''],
-    SENSOR_TYPE_WATT: ['Power', 'W', ''],
-    SENSOR_TYPE_LUMINANCE: ['Luminance', 'lx', ''],
-    SENSOR_TYPE_DEW_POINT: ['Dew Point', TEMP_CELSIUS, 'mdi:thermometer'],
-    SENSOR_TYPE_BAROMETRIC_PRESSURE: ['Barometric Pressure', 'kPa', ''],
+    SENSOR_TYPE_TEMPERATURE: ['Temperature', TEMP_CELSIUS, None,
+                              DEVICE_CLASS_TEMPERATURE],
+    SENSOR_TYPE_HUMIDITY: ['Humidity', '%', None, DEVICE_CLASS_HUMIDITY],
+    SENSOR_TYPE_RAINRATE: ['Rain rate', 'mm/h', 'mdi:water', None],
+    SENSOR_TYPE_RAINTOTAL: ['Rain total', 'mm', 'mdi:water', None],
+    SENSOR_TYPE_WINDDIRECTION: ['Wind direction', '', '', None],
+    SENSOR_TYPE_WINDAVERAGE: ['Wind average', 'm/s', '', None],
+    SENSOR_TYPE_WINDGUST: ['Wind gust', 'm/s', '', None],
+    SENSOR_TYPE_UV: ['UV', 'UV', '', None],
+    SENSOR_TYPE_WATT: ['Power', 'W', '', None],
+    SENSOR_TYPE_LUMINANCE: ['Luminance', 'lx', None, DEVICE_CLASS_ILLUMINANCE],
+    SENSOR_TYPE_DEW_POINT:
+        ['Dew Point', TEMP_CELSIUS, None, DEVICE_CLASS_TEMPERATURE],
+    SENSOR_TYPE_BAROMETRIC_PRESSURE: ['Barometric Pressure', 'kPa', '', None],
 }
 
 
@@ -117,3 +121,9 @@ class TelldusLiveSensor(TelldusLiveEntity):
         """Return the icon."""
         return SENSOR_TYPES[self._type][2] \
             if self._type in SENSOR_TYPES else None
+
+    @property
+    def device_class(self):
+        """Return the device class."""
+        return SENSOR_TYPES[self._type][3] \
+            if self._type in SENSOR_TYPES else None
diff --git a/homeassistant/components/sensor/vera.py b/homeassistant/components/sensor/vera.py
index c81c208e33e..eb8ccae768e 100644
--- a/homeassistant/components/sensor/vera.py
+++ b/homeassistant/components/sensor/vera.py
@@ -52,7 +52,7 @@ class VeraSensor(VeraDevice, Entity):
         if self.vera_device.category == veraApi.CATEGORY_TEMPERATURE_SENSOR:
             return self._temperature_units
         elif self.vera_device.category == veraApi.CATEGORY_LIGHT_SENSOR:
-            return 'lux'
+            return 'lx'
         elif self.vera_device.category == veraApi.CATEGORY_UV_SENSOR:
             return 'level'
         elif self.vera_device.category == veraApi.CATEGORY_HUMIDITY_SENSOR:
diff --git a/homeassistant/components/sensor/xiaomi_aqara.py b/homeassistant/components/sensor/xiaomi_aqara.py
index 497a3915154..3192d0d2f60 100644
--- a/homeassistant/components/sensor/xiaomi_aqara.py
+++ b/homeassistant/components/sensor/xiaomi_aqara.py
@@ -3,16 +3,18 @@ import logging
 
 from homeassistant.components.xiaomi_aqara import (PY_XIAOMI_GATEWAY,
                                                    XiaomiDevice)
-from homeassistant.const import TEMP_CELSIUS
+from homeassistant.const import (
+    DEVICE_CLASS_HUMIDITY, DEVICE_CLASS_ILLUMINANCE, DEVICE_CLASS_TEMPERATURE,
+    TEMP_CELSIUS)
 
 _LOGGER = logging.getLogger(__name__)
 
 SENSOR_TYPES = {
-    'temperature': [TEMP_CELSIUS, 'mdi:thermometer'],
-    'humidity': ['%', 'mdi:water-percent'],
-    'illumination': ['lm', 'mdi:weather-sunset'],
-    'lux': ['lx', 'mdi:weather-sunset'],
-    'pressure': ['hPa', 'mdi:gauge']
+    'temperature': [TEMP_CELSIUS, None, DEVICE_CLASS_TEMPERATURE],
+    'humidity': ['%', None, DEVICE_CLASS_HUMIDITY],
+    'illumination': ['lm', None, DEVICE_CLASS_ILLUMINANCE],
+    'lux': ['lx', None, DEVICE_CLASS_ILLUMINANCE],
+    'pressure': ['hPa', 'mdi:gauge', None]
 }
 
 
@@ -66,6 +68,12 @@ class XiaomiSensor(XiaomiDevice):
         except TypeError:
             return None
 
+    @property
+    def device_class(self):
+        """Return the device class of this entity."""
+        return SENSOR_TYPES.get(self._data_key)[2] \
+            if self._data_key in SENSOR_TYPES else None
+
     @property
     def state(self):
         """Return the state of the sensor."""
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 2e96e2f29c0..52a50ba9607 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -166,6 +166,12 @@ EVENT_SERVICE_REMOVED = 'service_removed'
 EVENT_LOGBOOK_ENTRY = 'logbook_entry'
 EVENT_THEMES_UPDATED = 'themes_updated'
 
+# #### DEVICE CLASSES ####
+DEVICE_CLASS_BATTERY = 'battery'
+DEVICE_CLASS_HUMIDITY = 'humidity'
+DEVICE_CLASS_ILLUMINANCE = 'illuminance'
+DEVICE_CLASS_TEMPERATURE = 'temperature'
+
 # #### STATES ####
 STATE_ON = 'on'
 STATE_OFF = 'off'
diff --git a/tests/components/homekit/test_get_accessories.py b/tests/components/homekit/test_get_accessories.py
index 71f9c8e6656..cff52b2ff20 100644
--- a/tests/components/homekit/test_get_accessories.py
+++ b/tests/components/homekit/test_get_accessories.py
@@ -99,10 +99,10 @@ class TestGetAccessories(unittest.TestCase):
             get_accessory(None, state, 2, {})
 
     def test_light_sensor(self):
-        """Test light sensor with device class lux."""
+        """Test light sensor with device class illuminance."""
         with patch.dict(TYPES, {'LightSensor': self.mock_type}):
             state = State('sensor.light', '900',
-                          {ATTR_DEVICE_CLASS: 'light'})
+                          {ATTR_DEVICE_CLASS: 'illuminance'})
             get_accessory(None, state, 2, {})
 
     def test_light_sensor_unit_lm(self):
@@ -112,13 +112,6 @@ class TestGetAccessories(unittest.TestCase):
                           {ATTR_UNIT_OF_MEASUREMENT: 'lm'})
             get_accessory(None, state, 2, {})
 
-    def test_light_sensor_unit_lux(self):
-        """Test light sensor with lux as unit."""
-        with patch.dict(TYPES, {'LightSensor': self.mock_type}):
-            state = State('sensor.light', '900',
-                          {ATTR_UNIT_OF_MEASUREMENT: 'lux'})
-            get_accessory(None, state, 2, {})
-
     def test_light_sensor_unit_lx(self):
         """Test light sensor with lx as unit."""
         with patch.dict(TYPES, {'LightSensor': self.mock_type}):