diff --git a/homeassistant/components/darksky/sensor.py b/homeassistant/components/darksky/sensor.py
index 1517f47a2d5..5157ab6ed7d 100644
--- a/homeassistant/components/darksky/sensor.py
+++ b/homeassistant/components/darksky/sensor.py
@@ -18,6 +18,7 @@ from homeassistant.const import (
     SPEED_KILOMETERS_PER_HOUR,
     SPEED_METERS_PER_SECOND,
     SPEED_MILES_PER_HOUR,
+    TEMP_CELSIUS,
     TIME_HOURS,
     UNIT_PERCENTAGE,
     UNIT_UV_INDEX,
@@ -134,31 +135,31 @@ SENSOR_TYPES = {
     ],
     "temperature": [
         "Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["currently", "hourly"],
     ],
     "apparent_temperature": [
         "Apparent Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["currently", "hourly"],
     ],
     "dew_point": [
         "Dew Point",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["currently", "hourly", "daily"],
     ],
@@ -244,81 +245,81 @@ SENSOR_TYPES = {
     ],
     "apparent_temperature_max": [
         "Daily High Apparent Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "apparent_temperature_high": [
         "Daytime High Apparent Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "apparent_temperature_min": [
         "Daily Low Apparent Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "apparent_temperature_low": [
         "Overnight Low Apparent Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "temperature_max": [
         "Daily High Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "temperature_high": [
         "Daytime High Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "temperature_min": [
         "Daily Low Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
     "temperature_low": [
         "Overnight Low Temperature",
-        "°C",
+        TEMP_CELSIUS,
         "°F",
-        "°C",
-        "°C",
-        "°C",
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
+        TEMP_CELSIUS,
         "mdi:thermometer",
         ["daily"],
     ],
diff --git a/homeassistant/components/eight_sleep/sensor.py b/homeassistant/components/eight_sleep/sensor.py
index dcee52db592..f5aa2cb1dca 100644
--- a/homeassistant/components/eight_sleep/sensor.py
+++ b/homeassistant/components/eight_sleep/sensor.py
@@ -1,7 +1,7 @@
 """Support for Eight Sleep sensors."""
 import logging
 
-from homeassistant.const import UNIT_PERCENTAGE
+from homeassistant.const import TEMP_CELSIUS, UNIT_PERCENTAGE
 
 from . import (
     CONF_SENSORS,
@@ -166,7 +166,7 @@ class EightUserSensor(EightSleepUserEntity):
             return "Score"
         if "bed_temp" in self._sensor:
             if self._units == "si":
-                return "°C"
+                return TEMP_CELSIUS
             return "°F"
         return None
 
@@ -329,7 +329,7 @@ class EightRoomSensor(EightSleepUserEntity):
     def unit_of_measurement(self):
         """Return the unit the value is expressed in."""
         if self._units == "si":
-            return "°C"
+            return TEMP_CELSIUS
         return "°F"
 
     @property
diff --git a/homeassistant/components/homematic/sensor.py b/homeassistant/components/homematic/sensor.py
index e8b97477546..c0a269bd582 100644
--- a/homeassistant/components/homematic/sensor.py
+++ b/homeassistant/components/homematic/sensor.py
@@ -9,6 +9,7 @@ from homeassistant.const import (
     ENERGY_WATT_HOUR,
     POWER_WATT,
     SPEED_KILOMETERS_PER_HOUR,
+    TEMP_CELSIUS,
     UNIT_PERCENTAGE,
     VOLUME_CUBIC_METERS,
 )
@@ -34,8 +35,8 @@ HM_STATE_HA_CAST = {
 
 HM_UNIT_HA_CAST = {
     "HUMIDITY": UNIT_PERCENTAGE,
-    "TEMPERATURE": "°C",
-    "ACTUAL_TEMPERATURE": "°C",
+    "TEMPERATURE": TEMP_CELSIUS,
+    "ACTUAL_TEMPERATURE": TEMP_CELSIUS,
     "BRIGHTNESS": "#",
     "POWER": POWER_WATT,
     "CURRENT": "mA",
diff --git a/homeassistant/components/miflora/sensor.py b/homeassistant/components/miflora/sensor.py
index 9d564c6536a..b8073f16d92 100644
--- a/homeassistant/components/miflora/sensor.py
+++ b/homeassistant/components/miflora/sensor.py
@@ -16,6 +16,7 @@ from homeassistant.const import (
     CONF_NAME,
     CONF_SCAN_INTERVAL,
     EVENT_HOMEASSISTANT_START,
+    TEMP_CELSIUS,
     TEMP_FAHRENHEIT,
     UNIT_PERCENTAGE,
 )
@@ -50,7 +51,7 @@ ATTR_LAST_SUCCESSFUL_UPDATE = "last_successful_update"
 
 # Sensor types are defined like: Name, units, icon
 SENSOR_TYPES = {
-    "temperature": ["Temperature", "°C", "mdi:thermometer"],
+    "temperature": ["Temperature", TEMP_CELSIUS, "mdi:thermometer"],
     "light": ["Light intensity", "lx", "mdi:white-balance-sunny"],
     "moisture": ["Moisture", UNIT_PERCENTAGE, "mdi:water-percent"],
     "conductivity": ["Conductivity", "µS/cm", "mdi:flash-circle"],
diff --git a/homeassistant/components/mitemp_bt/sensor.py b/homeassistant/components/mitemp_bt/sensor.py
index febfb93cf1d..b2033757693 100644
--- a/homeassistant/components/mitemp_bt/sensor.py
+++ b/homeassistant/components/mitemp_bt/sensor.py
@@ -15,6 +15,7 @@ from homeassistant.const import (
     DEVICE_CLASS_BATTERY,
     DEVICE_CLASS_HUMIDITY,
     DEVICE_CLASS_TEMPERATURE,
+    TEMP_CELSIUS,
     UNIT_PERCENTAGE,
 )
 import homeassistant.helpers.config_validation as cv
@@ -46,7 +47,7 @@ DEFAULT_TIMEOUT = 10
 
 # Sensor types are defined like: Name, units
 SENSOR_TYPES = {
-    "temperature": [DEVICE_CLASS_TEMPERATURE, "Temperature", "°C"],
+    "temperature": [DEVICE_CLASS_TEMPERATURE, "Temperature", TEMP_CELSIUS],
     "humidity": [DEVICE_CLASS_HUMIDITY, "Humidity", UNIT_PERCENTAGE],
     "battery": [DEVICE_CLASS_BATTERY, "Battery", UNIT_PERCENTAGE],
 }
diff --git a/homeassistant/components/notion/__init__.py b/homeassistant/components/notion/__init__.py
index a1c54d96299..5e8450ffdea 100644
--- a/homeassistant/components/notion/__init__.py
+++ b/homeassistant/components/notion/__init__.py
@@ -7,7 +7,12 @@ from aionotion.errors import InvalidCredentialsError, NotionError
 import voluptuous as vol
 
 from homeassistant.config_entries import SOURCE_IMPORT
-from homeassistant.const import ATTR_ATTRIBUTION, CONF_PASSWORD, CONF_USERNAME
+from homeassistant.const import (
+    ATTR_ATTRIBUTION,
+    CONF_PASSWORD,
+    CONF_USERNAME,
+    TEMP_CELSIUS,
+)
 from homeassistant.core import callback
 from homeassistant.exceptions import ConfigEntryNotReady
 from homeassistant.helpers import (
@@ -57,7 +62,7 @@ BINARY_SENSOR_TYPES = {
     SENSOR_WINDOW_HINGED_HORIZONTAL: ("Hinged Window", "window"),
     SENSOR_WINDOW_HINGED_VERTICAL: ("Hinged Window", "window"),
 }
-SENSOR_TYPES = {SENSOR_TEMPERATURE: ("Temperature", "temperature", "°C")}
+SENSOR_TYPES = {SENSOR_TEMPERATURE: ("Temperature", "temperature", TEMP_CELSIUS)}
 
 CONFIG_SCHEMA = vol.Schema(
     {
diff --git a/homeassistant/components/rainmachine/sensor.py b/homeassistant/components/rainmachine/sensor.py
index 4d48b0cd049..6f87c34d607 100644
--- a/homeassistant/components/rainmachine/sensor.py
+++ b/homeassistant/components/rainmachine/sensor.py
@@ -1,6 +1,7 @@
 """This platform provides support for sensor data from RainMachine."""
 import logging
 
+from homeassistant.const import TEMP_CELSIUS
 from homeassistant.core import callback
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
 
@@ -57,7 +58,7 @@ SENSORS = {
     TYPE_FREEZE_TEMP: (
         "Freeze Protect Temperature",
         "mdi:thermometer",
-        "°C",
+        TEMP_CELSIUS,
         "temperature",
         True,
         DATA_RESTRICTIONS_UNIVERSAL,
@@ -84,7 +85,7 @@ async def async_setup_entry(hass, entry, async_add_entities):
                 sensor_type,
                 (name, icon, unit, device_class, enabled_by_default, api_category),
             ) in SENSORS.items()
-        ],
+        ]
     )
 
 
diff --git a/homeassistant/components/velbus/climate.py b/homeassistant/components/velbus/climate.py
index 38d893e7343..8810f945ba9 100644
--- a/homeassistant/components/velbus/climate.py
+++ b/homeassistant/components/velbus/climate.py
@@ -38,7 +38,7 @@ class VelbusClimate(VelbusEntity, ClimateDevice):
     @property
     def temperature_unit(self):
         """Return the unit this state is expressed in."""
-        if self._module.get_unit(self._channel) == "°C":
+        if self._module.get_unit(self._channel) == TEMP_CELSIUS:
             return TEMP_CELSIUS
         return TEMP_FAHRENHEIT
 
diff --git a/homeassistant/components/zamg/sensor.py b/homeassistant/components/zamg/sensor.py
index 664ce0a38b6..0ead849b59a 100644
--- a/homeassistant/components/zamg/sensor.py
+++ b/homeassistant/components/zamg/sensor.py
@@ -18,6 +18,7 @@ from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
     SPEED_KILOMETERS_PER_HOUR,
+    TEMP_CELSIUS,
     UNIT_PERCENTAGE,
     __version__,
 )
@@ -56,9 +57,9 @@ SENSOR_TYPES = {
     ),
     "wind_max_bearing": ("Top Wind Bearing", "°", "WSR °", int),
     "sun_last_hour": ("Sun Last Hour", UNIT_PERCENTAGE, f"SO {UNIT_PERCENTAGE}", int),
-    "temperature": ("Temperature", "°C", "T °C", float),
+    "temperature": ("Temperature", TEMP_CELSIUS, f"T {TEMP_CELSIUS}", float),
     "precipitation": ("Precipitation", "l/m²", "N l/m²", float),
-    "dewpoint": ("Dew Point", "°C", "TP °C", float),
+    "dewpoint": ("Dew Point", TEMP_CELSIUS, f"TP {TEMP_CELSIUS}", float),
     # The following probably not useful for general consumption,
     # but we need them to fill in internal attributes
     "station_name": ("Station Name", None, "Name", str),
diff --git a/tests/components/abode/test_sensor.py b/tests/components/abode/test_sensor.py
index bfe20be0b8c..b4ce78faedd 100644
--- a/tests/components/abode/test_sensor.py
+++ b/tests/components/abode/test_sensor.py
@@ -6,6 +6,7 @@ from homeassistant.const import (
     ATTR_FRIENDLY_NAME,
     ATTR_UNIT_OF_MEASUREMENT,
     DEVICE_CLASS_HUMIDITY,
+    TEMP_CELSIUS,
 )
 
 from .common import setup_platform
@@ -41,4 +42,4 @@ async def test_attributes(hass):
     state = hass.states.get("sensor.environment_sensor_temperature")
     # Abodepy device JSON reports 19.5, but Home Assistant shows 19.4
     assert state.state == "19.4"
-    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == "°C"
+    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == TEMP_CELSIUS
diff --git a/tests/components/canary/test_sensor.py b/tests/components/canary/test_sensor.py
index 6cc33ddf610..1d559dbb7ba 100644
--- a/tests/components/canary/test_sensor.py
+++ b/tests/components/canary/test_sensor.py
@@ -12,7 +12,7 @@ from homeassistant.components.canary.sensor import (
     STATE_AIR_QUALITY_VERY_ABNORMAL,
     CanarySensor,
 )
-from homeassistant.const import UNIT_PERCENTAGE
+from homeassistant.const import TEMP_CELSIUS, UNIT_PERCENTAGE
 
 from tests.common import get_test_home_assistant
 from tests.components.canary.test_init import mock_device, mock_location
@@ -69,7 +69,7 @@ class TestCanarySensorSetup(unittest.TestCase):
         sensor.update()
 
         assert sensor.name == "Home Family Room Temperature"
-        assert sensor.unit_of_measurement == "°C"
+        assert sensor.unit_of_measurement == TEMP_CELSIUS
         assert sensor.state == 21.12
         assert sensor.icon == "mdi:thermometer"
 
diff --git a/tests/components/climate/test_device_trigger.py b/tests/components/climate/test_device_trigger.py
index eda215ebd0f..58aa3311771 100644
--- a/tests/components/climate/test_device_trigger.py
+++ b/tests/components/climate/test_device_trigger.py
@@ -4,6 +4,7 @@ import voluptuous_serialize
 
 import homeassistant.components.automation as automation
 from homeassistant.components.climate import DOMAIN, const, device_trigger
+from homeassistant.const import TEMP_CELSIUS
 from homeassistant.helpers import config_validation as cv, device_registry
 from homeassistant.setup import async_setup_component
 
@@ -228,13 +229,13 @@ async def test_get_trigger_capabilities_temp_humid(hass, type):
         capabilities["extra_fields"], custom_serializer=cv.custom_serializer
     ) == [
         {
-            "description": {"suffix": "°C"},
+            "description": {"suffix": TEMP_CELSIUS},
             "name": "above",
             "optional": True,
             "type": "float",
         },
         {
-            "description": {"suffix": "°C"},
+            "description": {"suffix": TEMP_CELSIUS},
             "name": "below",
             "optional": True,
             "type": "float",
diff --git a/tests/components/dyson/test_sensor.py b/tests/components/dyson/test_sensor.py
index b036e3bbbdb..7625b3c2a97 100644
--- a/tests/components/dyson/test_sensor.py
+++ b/tests/components/dyson/test_sensor.py
@@ -208,7 +208,7 @@ class DysonTest(unittest.TestCase):
         sensor.entity_id = "sensor.dyson_1"
         assert not sensor.should_poll
         assert sensor.state is None
-        assert sensor.unit_of_measurement == "°C"
+        assert sensor.unit_of_measurement == TEMP_CELSIUS
         assert sensor.name == "Device_name Temperature"
         assert sensor.entity_id == "sensor.dyson_1"
 
@@ -219,7 +219,7 @@ class DysonTest(unittest.TestCase):
         sensor.entity_id = "sensor.dyson_1"
         assert not sensor.should_poll
         assert sensor.state == 21.9
-        assert sensor.unit_of_measurement == "°C"
+        assert sensor.unit_of_measurement == TEMP_CELSIUS
         assert sensor.name == "Device_name Temperature"
         assert sensor.entity_id == "sensor.dyson_1"
 
@@ -241,7 +241,7 @@ class DysonTest(unittest.TestCase):
         sensor.entity_id = "sensor.dyson_1"
         assert not sensor.should_poll
         assert sensor.state == STATE_OFF
-        assert sensor.unit_of_measurement == "°C"
+        assert sensor.unit_of_measurement == TEMP_CELSIUS
         assert sensor.name == "Device_name Temperature"
         assert sensor.entity_id == "sensor.dyson_1"
 
diff --git a/tests/components/fritzbox/test_climate.py b/tests/components/fritzbox/test_climate.py
index b535b35e182..e2b3ec7ddea 100644
--- a/tests/components/fritzbox/test_climate.py
+++ b/tests/components/fritzbox/test_climate.py
@@ -5,6 +5,7 @@ from unittest.mock import Mock, patch
 import requests
 
 from homeassistant.components.fritzbox.climate import FritzboxThermostat
+from homeassistant.const import TEMP_CELSIUS
 
 
 class TestFritzboxClimate(unittest.TestCase):
@@ -51,7 +52,7 @@ class TestFritzboxClimate(unittest.TestCase):
 
     def test_temperature_unit(self):
         """Test temperature_unit property."""
-        assert "°C" == self.thermostat.temperature_unit
+        assert TEMP_CELSIUS == self.thermostat.temperature_unit
 
     def test_precision(self):
         """Test precision property."""
diff --git a/tests/components/hddtemp/test_sensor.py b/tests/components/hddtemp/test_sensor.py
index 1b6150fbc3f..cbaed220f11 100644
--- a/tests/components/hddtemp/test_sensor.py
+++ b/tests/components/hddtemp/test_sensor.py
@@ -3,6 +3,7 @@ import socket
 import unittest
 from unittest.mock import patch
 
+from homeassistant.const import TEMP_CELSIUS
 from homeassistant.setup import setup_component
 
 from tests.common import get_test_home_assistant
@@ -64,25 +65,25 @@ class TestHDDTempSensor(unittest.TestCase):
             "/dev/sda1": {
                 "device": "/dev/sda1",
                 "temperature": "29",
-                "unit_of_measurement": "°C",
+                "unit_of_measurement": TEMP_CELSIUS,
                 "model": "WDC WD30EZRX-12DC0B0",
             },
             "/dev/sdb1": {
                 "device": "/dev/sdb1",
                 "temperature": "32",
-                "unit_of_measurement": "°C",
+                "unit_of_measurement": TEMP_CELSIUS,
                 "model": "WDC WD15EADS-11P7B2",
             },
             "/dev/sdc1": {
                 "device": "/dev/sdc1",
                 "temperature": "29",
-                "unit_of_measurement": "°C",
+                "unit_of_measurement": TEMP_CELSIUS,
                 "model": "WDC WD20EARX-22MMMB0",
             },
             "/dev/sdd1": {
                 "device": "/dev/sdd1",
                 "temperature": "32",
-                "unit_of_measurement": "°C",
+                "unit_of_measurement": TEMP_CELSIUS,
                 "model": "WDC WD15EARS-00Z5B1",
             },
         }
diff --git a/tests/components/homekit/test_type_thermostats.py b/tests/components/homekit/test_type_thermostats.py
index 7fe2f41b736..d463231ba59 100644
--- a/tests/components/homekit/test_type_thermostats.py
+++ b/tests/components/homekit/test_type_thermostats.py
@@ -48,6 +48,7 @@ from homeassistant.const import (
     ATTR_TEMPERATURE,
     CONF_TEMPERATURE_UNIT,
     EVENT_HOMEASSISTANT_START,
+    TEMP_CELSIUS,
     TEMP_FAHRENHEIT,
 )
 from homeassistant.core import CoreState
@@ -86,7 +87,7 @@ async def test_thermostat(hass, hk_driver, cls, events):
                 HVAC_MODE_COOL,
                 HVAC_MODE_OFF,
                 HVAC_MODE_AUTO,
-            ],
+            ]
         },
     )
     await hass.async_block_till_done()
@@ -418,14 +419,14 @@ async def test_thermostat_humidity(hass, hk_driver, cls, events):
     assert acc.char_target_humidity.properties[PROP_MIN_VALUE] == DEFAULT_MIN_HUMIDITY
 
     hass.states.async_set(
-        entity_id, HVAC_MODE_HEAT_COOL, {ATTR_HUMIDITY: 65, ATTR_CURRENT_HUMIDITY: 40},
+        entity_id, HVAC_MODE_HEAT_COOL, {ATTR_HUMIDITY: 65, ATTR_CURRENT_HUMIDITY: 40}
     )
     await hass.async_block_till_done()
     assert acc.char_current_humidity.value == 40
     assert acc.char_target_humidity.value == 65
 
     hass.states.async_set(
-        entity_id, HVAC_MODE_COOL, {ATTR_HUMIDITY: 35, ATTR_CURRENT_HUMIDITY: 70},
+        entity_id, HVAC_MODE_COOL, {ATTR_HUMIDITY: 35, ATTR_CURRENT_HUMIDITY: 70}
     )
     await hass.async_block_till_done()
     assert acc.char_current_humidity.value == 70
@@ -618,7 +619,7 @@ async def test_thermostat_restore(hass, hk_driver, cls, events):
     registry = await entity_registry.async_get_registry(hass)
 
     registry.async_get_or_create(
-        "climate", "generic", "1234", suggested_object_id="simple",
+        "climate", "generic", "1234", suggested_object_id="simple"
     )
     registry.async_get_or_create(
         "climate",
@@ -898,7 +899,7 @@ async def test_water_heater(hass, hk_driver, cls, events):
     assert call_set_temperature[0].data[ATTR_TEMPERATURE] == 52.0
     assert acc.char_target_temp.value == 52.0
     assert len(events) == 1
-    assert events[-1].data[ATTR_VALUE] == "52.0°C"
+    assert events[-1].data[ATTR_VALUE] == f"52.0{TEMP_CELSIUS}"
 
     await hass.async_add_executor_job(acc.char_target_heat_cool.client_update_value, 0)
     await hass.async_block_till_done()
@@ -975,7 +976,7 @@ async def test_water_heater_restore(hass, hk_driver, cls, events):
     registry = await entity_registry.async_get_registry(hass)
 
     registry.async_get_or_create(
-        "water_heater", "generic", "1234", suggested_object_id="simple",
+        "water_heater", "generic", "1234", suggested_object_id="simple"
     )
     registry.async_get_or_create(
         "water_heater",
diff --git a/tests/components/mhz19/test_sensor.py b/tests/components/mhz19/test_sensor.py
index 0eb86f0198e..598144f5a25 100644
--- a/tests/components/mhz19/test_sensor.py
+++ b/tests/components/mhz19/test_sensor.py
@@ -4,7 +4,11 @@ from unittest.mock import DEFAULT, Mock, patch
 
 import homeassistant.components.mhz19.sensor as mhz19
 from homeassistant.components.sensor import DOMAIN
-from homeassistant.const import CONCENTRATION_PARTS_PER_MILLION, TEMP_FAHRENHEIT
+from homeassistant.const import (
+    CONCENTRATION_PARTS_PER_MILLION,
+    TEMP_CELSIUS,
+    TEMP_FAHRENHEIT,
+)
 from homeassistant.setup import setup_component
 
 from tests.common import assert_setup_component, get_test_home_assistant
@@ -115,7 +119,7 @@ class TestMHZ19Sensor(unittest.TestCase):
 
         assert sensor.name == "name: Temperature"
         assert sensor.state == 24
-        assert sensor.unit_of_measurement == "°C"
+        assert sensor.unit_of_measurement == TEMP_CELSIUS
         assert sensor.should_poll
         assert sensor.device_state_attributes == {"co2_concentration": 1000}
 
diff --git a/tests/components/min_max/test_sensor.py b/tests/components/min_max/test_sensor.py
index 891f99ac67f..10860d0fbe4 100644
--- a/tests/components/min_max/test_sensor.py
+++ b/tests/components/min_max/test_sensor.py
@@ -221,7 +221,7 @@ class TestMinMaxSensor(unittest.TestCase):
         state = self.hass.states.get("sensor.test")
 
         assert str(float(self.values[0])) == state.state
-        assert state.attributes.get("unit_of_measurement") == "°C"
+        assert state.attributes.get("unit_of_measurement") == TEMP_CELSIUS
 
         self.hass.states.set(
             entity_ids[1], self.values[1], {ATTR_UNIT_OF_MEASUREMENT: TEMP_FAHRENHEIT}
diff --git a/tests/components/mqtt/test_init.py b/tests/components/mqtt/test_init.py
index de8444446d5..e70a53caf9d 100644
--- a/tests/components/mqtt/test_init.py
+++ b/tests/components/mqtt/test_init.py
@@ -16,6 +16,7 @@ from homeassistant.const import (
     ATTR_SERVICE,
     EVENT_CALL_SERVICE,
     EVENT_HOMEASSISTANT_STOP,
+    TEMP_CELSIUS,
 )
 from homeassistant.core import callback
 from homeassistant.exceptions import ConfigEntryNotReady
@@ -342,7 +343,7 @@ class TestMQTTCallbacks(unittest.TestCase):
         mqtt.subscribe(self.hass, "test-topic", self.record_calls, encoding="ascii")
         mqtt.subscribe(self.hass, "test-topic", self.record_calls)
 
-        fire_mqtt_message(self.hass, "test-topic", "°C")
+        fire_mqtt_message(self.hass, "test-topic", TEMP_CELSIUS)
 
         self.hass.block_till_done()
         assert len(self.calls) == 1
diff --git a/tests/components/nexia/test_sensor.py b/tests/components/nexia/test_sensor.py
index 6e258d0ad55..518993cf24a 100644
--- a/tests/components/nexia/test_sensor.py
+++ b/tests/components/nexia/test_sensor.py
@@ -1,5 +1,7 @@
 """The sensor tests for the nexia platform."""
 
+from homeassistant.const import TEMP_CELSIUS
+
 from .util import async_init_integration
 
 
@@ -15,7 +17,7 @@ async def test_create_sensors(hass):
         "attribution": "Data provided by mynexia.com",
         "device_class": "temperature",
         "friendly_name": "Nick Office Temperature",
-        "unit_of_measurement": "°C",
+        "unit_of_measurement": TEMP_CELSIUS,
     }
     # Only test for a subset of attributes in case
     # HA changes the implementation and a new one appears
@@ -82,7 +84,7 @@ async def test_create_sensors(hass):
         "attribution": "Data provided by mynexia.com",
         "device_class": "temperature",
         "friendly_name": "Master Suite Outdoor Temperature",
-        "unit_of_measurement": "°C",
+        "unit_of_measurement": TEMP_CELSIUS,
     }
     # Only test for a subset of attributes in case
     # HA changes the implementation and a new one appears
diff --git a/tests/components/rflink/test_sensor.py b/tests/components/rflink/test_sensor.py
index f60b1c3584c..77f911f0ed0 100644
--- a/tests/components/rflink/test_sensor.py
+++ b/tests/components/rflink/test_sensor.py
@@ -12,7 +12,7 @@ from homeassistant.components.rflink import (
     EVENT_KEY_SENSOR,
     TMP_ENTITY,
 )
-from homeassistant.const import STATE_UNKNOWN, UNIT_PERCENTAGE
+from homeassistant.const import STATE_UNKNOWN, TEMP_CELSIUS, UNIT_PERCENTAGE
 
 from tests.components.rflink.test_init import mock_rflink
 
@@ -42,23 +42,27 @@ async def test_default_setup(hass, monkeypatch):
     config_sensor = hass.states.get("sensor.test")
     assert config_sensor
     assert config_sensor.state == "unknown"
-    assert config_sensor.attributes["unit_of_measurement"] == "°C"
+    assert config_sensor.attributes["unit_of_measurement"] == TEMP_CELSIUS
 
     # test event for config sensor
-    event_callback({"id": "test", "sensor": "temperature", "value": 1, "unit": "°C"})
+    event_callback(
+        {"id": "test", "sensor": "temperature", "value": 1, "unit": TEMP_CELSIUS}
+    )
     await hass.async_block_till_done()
 
     assert hass.states.get("sensor.test").state == "1"
 
     # test event for new unconfigured sensor
-    event_callback({"id": "test2", "sensor": "temperature", "value": 0, "unit": "°C"})
+    event_callback(
+        {"id": "test2", "sensor": "temperature", "value": 0, "unit": TEMP_CELSIUS}
+    )
     await hass.async_block_till_done()
 
     # test  state of new sensor
     new_sensor = hass.states.get("sensor.test2")
     assert new_sensor
     assert new_sensor.state == "0"
-    assert new_sensor.attributes["unit_of_measurement"] == "°C"
+    assert new_sensor.attributes["unit_of_measurement"] == TEMP_CELSIUS
     assert new_sensor.attributes["icon"] == "mdi:thermometer"
 
 
@@ -73,7 +77,9 @@ async def test_disable_automatic_add(hass, monkeypatch):
     event_callback, _, _, _ = await mock_rflink(hass, config, DOMAIN, monkeypatch)
 
     # test event for new unconfigured sensor
-    event_callback({"id": "test2", "sensor": "temperature", "value": 0, "unit": "°C"})
+    event_callback(
+        {"id": "test2", "sensor": "temperature", "value": 0, "unit": TEMP_CELSIUS}
+    )
     await hass.async_block_till_done()
 
     # make sure new device is not added
diff --git a/tests/components/spaceapi/test_init.py b/tests/components/spaceapi/test_init.py
index 78c7991d9b3..891adac91ae 100644
--- a/tests/components/spaceapi/test_init.py
+++ b/tests/components/spaceapi/test_init.py
@@ -5,7 +5,7 @@ from unittest.mock import patch
 import pytest
 
 from homeassistant.components.spaceapi import DOMAIN, SPACEAPI_VERSION, URL_API_SPACEAPI
-from homeassistant.const import UNIT_PERCENTAGE
+from homeassistant.const import TEMP_CELSIUS, UNIT_PERCENTAGE
 from homeassistant.setup import async_setup_component
 
 from tests.common import mock_coro
@@ -60,8 +60,8 @@ CONFIG = {
 
 SENSOR_OUTPUT = {
     "temperature": [
-        {"location": "Home", "name": "temp1", "unit": "°C", "value": "25"},
-        {"location": "Home", "name": "temp2", "unit": "°C", "value": "23"},
+        {"location": "Home", "name": "temp1", "unit": TEMP_CELSIUS, "value": "25"},
+        {"location": "Home", "name": "temp2", "unit": TEMP_CELSIUS, "value": "23"},
     ],
     "humidity": [
         {"location": "Home", "name": "hum1", "unit": UNIT_PERCENTAGE, "value": "88"}
@@ -75,8 +75,12 @@ def mock_client(hass, hass_client):
     with patch("homeassistant.components.spaceapi", return_value=mock_coro(True)):
         hass.loop.run_until_complete(async_setup_component(hass, "spaceapi", CONFIG))
 
-    hass.states.async_set("test.temp1", 25, attributes={"unit_of_measurement": "°C"})
-    hass.states.async_set("test.temp2", 23, attributes={"unit_of_measurement": "°C"})
+    hass.states.async_set(
+        "test.temp1", 25, attributes={"unit_of_measurement": TEMP_CELSIUS}
+    )
+    hass.states.async_set(
+        "test.temp2", 23, attributes={"unit_of_measurement": TEMP_CELSIUS}
+    )
     hass.states.async_set(
         "test.hum1", 88, attributes={"unit_of_measurement": UNIT_PERCENTAGE}
     )
diff --git a/tests/components/statistics/test_sensor.py b/tests/components/statistics/test_sensor.py
index df79d0750b4..61a0abb6265 100644
--- a/tests/components/statistics/test_sensor.py
+++ b/tests/components/statistics/test_sensor.py
@@ -102,7 +102,7 @@ class TestStatisticsSensor(unittest.TestCase):
         assert self.mean == state.attributes.get("mean")
         assert self.count == state.attributes.get("count")
         assert self.total == state.attributes.get("total")
-        assert "°C" == state.attributes.get("unit_of_measurement")
+        assert TEMP_CELSIUS == state.attributes.get("unit_of_measurement")
         assert self.change == state.attributes.get("change")
         assert self.average_change == state.attributes.get("average_change")
 
diff --git a/tests/components/zha/test_sensor.py b/tests/components/zha/test_sensor.py
index 50b85f5720f..dbd2e8f7c3a 100644
--- a/tests/components/zha/test_sensor.py
+++ b/tests/components/zha/test_sensor.py
@@ -41,7 +41,7 @@ async def async_test_humidity(hass, cluster, entity_id):
 async def async_test_temperature(hass, cluster, entity_id):
     """Test temperature sensor."""
     await send_attributes_report(hass, cluster, {1: 1, 0: 2900, 2: 100})
-    assert_state(hass, entity_id, "29.0", "°C")
+    assert_state(hass, entity_id, "29.0", TEMP_CELSIUS)
 
 
 async def async_test_pressure(hass, cluster, entity_id):