diff --git a/homeassistant/components/bitcoin/sensor.py b/homeassistant/components/bitcoin/sensor.py
index cf2b76bf25f..a488fa1e2fa 100644
--- a/homeassistant/components/bitcoin/sensor.py
+++ b/homeassistant/components/bitcoin/sensor.py
@@ -124,45 +124,45 @@ class BitcoinSensor(Entity):
             self._state = ticker[self._currency].p15min
             self._unit_of_measurement = self._currency
         elif self.type == "trade_volume_btc":
-            self._state = "{0:.1f}".format(stats.trade_volume_btc)
+            self._state = f"{stats.trade_volume_btc:.1f}"
         elif self.type == "miners_revenue_usd":
-            self._state = "{0:.0f}".format(stats.miners_revenue_usd)
+            self._state = f"{stats.miners_revenue_usd:.0f}"
         elif self.type == "btc_mined":
-            self._state = "{}".format(stats.btc_mined * 0.00000001)
+            self._state = str(stats.btc_mined * 0.00000001)
         elif self.type == "trade_volume_usd":
-            self._state = "{0:.1f}".format(stats.trade_volume_usd)
+            self._state = f"{stats.trade_volume_usd:.1f}"
         elif self.type == "difficulty":
-            self._state = "{0:.0f}".format(stats.difficulty)
+            self._state = f"{stats.difficulty:.0f}"
         elif self.type == "minutes_between_blocks":
-            self._state = "{0:.2f}".format(stats.minutes_between_blocks)
+            self._state = f"{stats.minutes_between_blocks:.2f}"
         elif self.type == "number_of_transactions":
-            self._state = "{}".format(stats.number_of_transactions)
+            self._state = str(stats.number_of_transactions)
         elif self.type == "hash_rate":
-            self._state = "{0:.1f}".format(stats.hash_rate * 0.000001)
+            self._state = f"{stats.hash_rate * 0.000001:.1f}"
         elif self.type == "timestamp":
             self._state = stats.timestamp
         elif self.type == "mined_blocks":
-            self._state = "{}".format(stats.mined_blocks)
+            self._state = str(stats.mined_blocks)
         elif self.type == "blocks_size":
-            self._state = "{0:.1f}".format(stats.blocks_size)
+            self._state = f"{stats.blocks_size:.1f}"
         elif self.type == "total_fees_btc":
-            self._state = "{0:.2f}".format(stats.total_fees_btc * 0.00000001)
+            self._state = f"{stats.total_fees_btc * 0.00000001:.2f}"
         elif self.type == "total_btc_sent":
-            self._state = "{0:.2f}".format(stats.total_btc_sent * 0.00000001)
+            self._state = f"{stats.total_btc_sent * 0.00000001:.2f}"
         elif self.type == "estimated_btc_sent":
-            self._state = "{0:.2f}".format(stats.estimated_btc_sent * 0.00000001)
+            self._state = f"{stats.estimated_btc_sent * 0.00000001:.2f}"
         elif self.type == "total_btc":
-            self._state = "{0:.2f}".format(stats.total_btc * 0.00000001)
+            self._state = f"{stats.total_btc * 0.00000001:.2f}"
         elif self.type == "total_blocks":
-            self._state = "{0:.0f}".format(stats.total_blocks)
+            self._state = f"{stats.total_blocks:.0f}"
         elif self.type == "next_retarget":
-            self._state = "{0:.2f}".format(stats.next_retarget)
+            self._state = f"{stats.next_retarget:.2f}"
         elif self.type == "estimated_transaction_volume_usd":
-            self._state = "{0:.2f}".format(stats.estimated_transaction_volume_usd)
+            self._state = f"{stats.estimated_transaction_volume_usd:.2f}"
         elif self.type == "miners_revenue_btc":
-            self._state = "{0:.1f}".format(stats.miners_revenue_btc * 0.00000001)
+            self._state = f"{stats.miners_revenue_btc * 0.00000001:.1f}"
         elif self.type == "market_price_usd":
-            self._state = "{0:.2f}".format(stats.market_price_usd)
+            self._state = f"{stats.market_price_usd:.2f}"
 
 
 class BitcoinData:
diff --git a/homeassistant/components/bloomsky/binary_sensor.py b/homeassistant/components/bloomsky/binary_sensor.py
index cc6562a0bc1..516fa42cb5c 100644
--- a/homeassistant/components/bloomsky/binary_sensor.py
+++ b/homeassistant/components/bloomsky/binary_sensor.py
@@ -40,7 +40,7 @@ class BloomSkySensor(BinarySensorDevice):
         self._bloomsky = bs
         self._device_id = device["DeviceID"]
         self._sensor_name = sensor_name
-        self._name = "{} {}".format(device["DeviceName"], sensor_name)
+        self._name = f"{device['DeviceName']} {sensor_name}"
         self._state = None
         self._unique_id = f"{self._device_id}-{self._sensor_name}"
 
diff --git a/homeassistant/components/bloomsky/sensor.py b/homeassistant/components/bloomsky/sensor.py
index 84871b7b30e..2ffdb8efab0 100644
--- a/homeassistant/components/bloomsky/sensor.py
+++ b/homeassistant/components/bloomsky/sensor.py
@@ -70,7 +70,7 @@ class BloomSkySensor(Entity):
         self._bloomsky = bs
         self._device_id = device["DeviceID"]
         self._sensor_name = sensor_name
-        self._name = "{} {}".format(device["DeviceName"], sensor_name)
+        self._name = f"{device['DeviceName']} {sensor_name}"
         self._state = None
         self._unique_id = f"{self._device_id}-{self._sensor_name}"
 
diff --git a/homeassistant/components/bluesound/media_player.py b/homeassistant/components/bluesound/media_player.py
index db5c65eab8b..3ca9cb1f623 100644
--- a/homeassistant/components/bluesound/media_player.py
+++ b/homeassistant/components/bluesound/media_player.py
@@ -500,7 +500,7 @@ class BluesoundPlayer(MediaPlayerDevice):
                     "image": item.get("@image", ""),
                     "is_raw_url": True,
                     "url2": item.get("@url", ""),
-                    "url": "Preset?id={}".format(item.get("@id", "")),
+                    "url": f"Preset?id={item.get('@id', '')}",
                 }
             )
 
@@ -934,9 +934,7 @@ class BluesoundPlayer(MediaPlayerDevice):
             return
 
         selected_source = items[0]
-        url = "Play?url={}&preset_id&image={}".format(
-            selected_source["url"], selected_source["image"]
-        )
+        url = f"Play?url={selected_source['url']}&preset_id&image={selected_source['image']}"
 
         if "is_raw_url" in selected_source and selected_source["is_raw_url"]:
             url = selected_source["url"]
@@ -1002,7 +1000,7 @@ class BluesoundPlayer(MediaPlayerDevice):
         if self.is_grouped and not self.is_master:
             return
 
-        return await self.send_bluesound_command("Play?seek={}".format(float(position)))
+        return await self.send_bluesound_command(f"Play?seek={float(position)}")
 
     async def async_play_media(self, media_type, media_id, **kwargs):
         """
diff --git a/homeassistant/components/bom/camera.py b/homeassistant/components/bom/camera.py
index 7460b84f734..3bbd9e39164 100644
--- a/homeassistant/components/bom/camera.py
+++ b/homeassistant/components/bom/camera.py
@@ -75,16 +75,12 @@ def _validate_schema(config):
     if config.get(CONF_LOCATION) is None:
         if not all(config.get(x) for x in (CONF_ID, CONF_DELTA, CONF_FRAMES)):
             raise vol.Invalid(
-                "Specify '{}', '{}' and '{}' when '{}' is unspecified".format(
-                    CONF_ID, CONF_DELTA, CONF_FRAMES, CONF_LOCATION
-                )
+                f"Specify '{CONF_ID}', '{CONF_DELTA}' and '{CONF_FRAMES}' when '{CONF_LOCATION}' is unspecified"
             )
     return config
 
 
-LOCATIONS_MSG = "Set '{}' to one of: {}".format(
-    CONF_LOCATION, ", ".join(sorted(LOCATIONS))
-)
+LOCATIONS_MSG = f"Set '{CONF_LOCATION}' to one of: {', '.join(sorted(LOCATIONS))}"
 XOR_MSG = f"Specify exactly one of '{CONF_ID}' or '{CONF_LOCATION}'"
 
 PLATFORM_SCHEMA = vol.All(
@@ -106,7 +102,7 @@ PLATFORM_SCHEMA = vol.All(
 
 def setup_platform(hass, config, add_entities, discovery_info=None):
     """Set up BOM radar-loop camera component."""
-    location = config.get(CONF_LOCATION) or "ID {}".format(config.get(CONF_ID))
+    location = config.get(CONF_LOCATION) or f"ID {config.get(CONF_ID)}"
     name = config.get(CONF_NAME) or f"BOM Radar Loop - {location}"
     args = [
         config.get(x)
diff --git a/homeassistant/components/bom/sensor.py b/homeassistant/components/bom/sensor.py
index 0981f1b0a86..2a38a3e60b0 100644
--- a/homeassistant/components/bom/sensor.py
+++ b/homeassistant/components/bom/sensor.py
@@ -27,7 +27,6 @@ from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
 import homeassistant.util.dt as dt_util
 
-_RESOURCE = "http://www.bom.gov.au/fwo/{}/{}.{}.json"
 _LOGGER = logging.getLogger(__name__)
 
 ATTR_LAST_UPDATE = "last_update"
@@ -159,9 +158,9 @@ class BOMCurrentSensor(Entity):
     def name(self):
         """Return the name of the sensor."""
         if self.stationname is None:
-            return "BOM {}".format(SENSOR_TYPES[self._condition][0])
+            return f"BOM {SENSOR_TYPES[self._condition][0]}"
 
-        return "BOM {} {}".format(self.stationname, SENSOR_TYPES[self._condition][0])
+        return f"BOM {self.stationname} {SENSOR_TYPES[self._condition][0]}"
 
     @property
     def state(self):
@@ -203,7 +202,10 @@ class BOMCurrentData:
 
     def _build_url(self):
         """Build the URL for the requests."""
-        url = _RESOURCE.format(self._zone_id, self._zone_id, self._wmo_id)
+        url = (
+            f"http://www.bom.gov.au/fwo/{self._zone_id}"
+            f"/{self._zone_id}.{self._wmo_id}.json"
+        )
         _LOGGER.debug("BOM URL: %s", url)
         return url
 
@@ -310,10 +312,10 @@ def _get_bom_stations():
         r'(?P=zone)\.(?P<wmo>\d\d\d\d\d).shtml">'
     )
     for state in ("nsw", "vic", "qld", "wa", "tas", "nt"):
-        url = "http://www.bom.gov.au/{0}/observations/{0}all.shtml".format(state)
+        url = f"http://www.bom.gov.au/{state}/observations/{state}all.shtml"
         for zone_id, wmo_id in re.findall(pattern, requests.get(url).text):
             zones[wmo_id] = zone_id
-    return {"{}.{}".format(zones[k], k): latlon[k] for k in set(latlon) & set(zones)}
+    return {f"{zones[k]}.{k}": latlon[k] for k in set(latlon) & set(zones)}
 
 
 def bom_stations(cache_dir):
diff --git a/homeassistant/components/bom/weather.py b/homeassistant/components/bom/weather.py
index 2513c7c4c40..94b9960c851 100644
--- a/homeassistant/components/bom/weather.py
+++ b/homeassistant/components/bom/weather.py
@@ -49,7 +49,7 @@ class BOMWeather(WeatherEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "BOM {}".format(self.stationname or "(unknown station)")
+        return f"BOM {self.stationname or '(unknown station)'}"
 
     @property
     def condition(self):
diff --git a/homeassistant/components/broadlink/remote.py b/homeassistant/components/broadlink/remote.py
index 96698e5b02f..714b5dfec34 100644
--- a/homeassistant/components/broadlink/remote.py
+++ b/homeassistant/components/broadlink/remote.py
@@ -44,9 +44,7 @@ DEFAULT_TIMEOUT = 5
 
 SCAN_INTERVAL = timedelta(minutes=2)
 
-CODE_STORAGE_KEY = "broadlink_{}_codes"
 CODE_STORAGE_VERSION = 1
-FLAG_STORAGE_KEY = "broadlink_{}_flags"
 FLAG_STORAGE_VERSION = 1
 FLAG_SAVE_DELAY = 15
 
@@ -96,8 +94,8 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
 
     api = broadlink.rm((host, DEFAULT_PORT), mac_addr, None)
     api.timeout = timeout
-    code_storage = Store(hass, CODE_STORAGE_VERSION, CODE_STORAGE_KEY.format(unique_id))
-    flag_storage = Store(hass, FLAG_STORAGE_VERSION, FLAG_STORAGE_KEY.format(unique_id))
+    code_storage = Store(hass, CODE_STORAGE_VERSION, f"broadlink_{unique_id}_codes")
+    flag_storage = Store(hass, FLAG_STORAGE_VERSION, f"broadlink_{unique_id}_flags")
     remote = BroadlinkRemote(name, unique_id, api, code_storage, flag_storage)
 
     connected, loaded = (False, False)
diff --git a/homeassistant/components/broadlink/sensor.py b/homeassistant/components/broadlink/sensor.py
index 9f3087335c8..408593e337d 100644
--- a/homeassistant/components/broadlink/sensor.py
+++ b/homeassistant/components/broadlink/sensor.py
@@ -67,7 +67,7 @@ class BroadlinkSensor(Entity):
 
     def __init__(self, name, broadlink_data, sensor_type):
         """Initialize the sensor."""
-        self._name = "{} {}".format(name, SENSOR_TYPES[sensor_type][0])
+        self._name = f"{name} {SENSOR_TYPES[sensor_type][0]}"
         self._state = None
         self._is_available = False
         self._type = sensor_type
diff --git a/homeassistant/components/broadlink/switch.py b/homeassistant/components/broadlink/switch.py
index 78738870aaa..9b986ae75d4 100644
--- a/homeassistant/components/broadlink/switch.py
+++ b/homeassistant/components/broadlink/switch.py
@@ -7,11 +7,7 @@ import socket
 import broadlink
 import voluptuous as vol
 
-from homeassistant.components.switch import (
-    ENTITY_ID_FORMAT,
-    PLATFORM_SCHEMA,
-    SwitchDevice,
-)
+from homeassistant.components.switch import DOMAIN, PLATFORM_SCHEMA, SwitchDevice
 from homeassistant.const import (
     CONF_COMMAND_OFF,
     CONF_COMMAND_ON,
@@ -159,7 +155,7 @@ class BroadlinkRMSwitch(SwitchDevice, RestoreEntity):
         self, name, friendly_name, device, command_on, command_off, retry_times
     ):
         """Initialize the switch."""
-        self.entity_id = ENTITY_ID_FORMAT.format(slugify(name))
+        self.entity_id = f"{DOMAIN}.{slugify(name)}"
         self._name = friendly_name
         self._state = False
         self._command_on = command_on
diff --git a/homeassistant/components/brottsplatskartan/sensor.py b/homeassistant/components/brottsplatskartan/sensor.py
index 282433aa7a4..feb066a6f3f 100644
--- a/homeassistant/components/brottsplatskartan/sensor.py
+++ b/homeassistant/components/brottsplatskartan/sensor.py
@@ -69,7 +69,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
 
     # Every Home Assistant instance should have their own unique
     # app parameter: https://brottsplatskartan.se/sida/api
-    app = "ha-{}".format(uuid.getnode())
+    app = f"ha-{uuid.getnode()}"
 
     bpk = brottsplatskartan.BrottsplatsKartan(
         app=app, area=area, latitude=latitude, longitude=longitude
diff --git a/homeassistant/components/brunt/cover.py b/homeassistant/components/brunt/cover.py
index 373c3339441..b3a007277c3 100644
--- a/homeassistant/components/brunt/cover.py
+++ b/homeassistant/components/brunt/cover.py
@@ -56,9 +56,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     except (TypeError, KeyError, NameError, ValueError) as ex:
         _LOGGER.error("%s", ex)
         hass.components.persistent_notification.create(
-            "Error: {}<br />"
-            "You will need to restart hass after fixing."
-            "".format(ex),
+            "Error: {ex}<br />You will need to restart hass after fixing.",
             title=NOTIFICATION_TITLE,
             notification_id=NOTIFICATION_ID,
         )
diff --git a/homeassistant/components/buienradar/camera.py b/homeassistant/components/buienradar/camera.py
index b41b3220b40..b685bdb5c73 100644
--- a/homeassistant/components/buienradar/camera.py
+++ b/homeassistant/components/buienradar/camera.py
@@ -17,8 +17,6 @@ CONF_DIMENSION = "dimension"
 CONF_DELTA = "delta"
 CONF_COUNTRY = "country_code"
 
-RADAR_MAP_URL_TEMPLATE = "https://api.buienradar.nl/image/1.0/RadarMap{c}?w={w}&h={h}"
-
 _LOG = logging.getLogger(__name__)
 
 # Maximum range according to docs
@@ -112,8 +110,9 @@ class BuienradarCam(Camera):
         """Retrieve new radar image and return whether this succeeded."""
         session = async_get_clientsession(self.hass)
 
-        url = RADAR_MAP_URL_TEMPLATE.format(
-            c=self._country, w=self._dimension, h=self._dimension
+        url = (
+            f"https://api.buienradar.nl/image/1.0/RadarMap{self._country}"
+            f"?w={self._dimension}&h={self._dimension}"
         )
 
         if self._last_modified:
diff --git a/homeassistant/components/buienradar/weather.py b/homeassistant/components/buienradar/weather.py
index 98cbb2f5e43..32e8babde90 100644
--- a/homeassistant/components/buienradar/weather.py
+++ b/homeassistant/components/buienradar/weather.py
@@ -113,8 +113,8 @@ class BrWeather(WeatherEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return self._stationname or "BR {}".format(
-            self._data.stationname or "(unknown station)"
+        return (
+            self._stationname or f"BR {self._data.stationname or '(unknown station)'}"
         )
 
     @property
diff --git a/homeassistant/components/caldav/calendar.py b/homeassistant/components/caldav/calendar.py
index 7cdf69a0c33..579755709d1 100644
--- a/homeassistant/components/caldav/calendar.py
+++ b/homeassistant/components/caldav/calendar.py
@@ -88,9 +88,7 @@ def setup_platform(hass, config, add_entities, disc_info=None):
                 continue
 
             name = cust_calendar[CONF_NAME]
-            device_id = "{} {}".format(
-                cust_calendar[CONF_CALENDAR], cust_calendar[CONF_NAME]
-            )
+            device_id = f"{cust_calendar[CONF_CALENDAR]} {cust_calendar[CONF_NAME]}"
             entity_id = generate_entity_id(ENTITY_ID_FORMAT, device_id, hass=hass)
             calendar_devices.append(
                 WebDavCalendarEventDevice(
diff --git a/homeassistant/components/co2signal/sensor.py b/homeassistant/components/co2signal/sensor.py
index 7160d140b3f..31a06c94120 100644
--- a/homeassistant/components/co2signal/sensor.py
+++ b/homeassistant/components/co2signal/sensor.py
@@ -65,9 +65,7 @@ class CO2Sensor(Entity):
         if country_code is not None:
             device_name = country_code
         else:
-            device_name = "{lat}/{lon}".format(
-                lat=round(self._latitude, 2), lon=round(self._longitude, 2)
-            )
+            device_name = f"{round(self._latitude, 2)}/{round(self._longitude, 2)}"
 
         self._friendly_name = f"CO2 intensity - {device_name}"
 
diff --git a/homeassistant/components/coinbase/sensor.py b/homeassistant/components/coinbase/sensor.py
index 4a3e85d5e43..a13dfef11da 100644
--- a/homeassistant/components/coinbase/sensor.py
+++ b/homeassistant/components/coinbase/sensor.py
@@ -75,9 +75,7 @@ class AccountSensor(Entity):
         """Return the state attributes of the sensor."""
         return {
             ATTR_ATTRIBUTION: ATTRIBUTION,
-            ATTR_NATIVE_BALANCE: "{} {}".format(
-                self._native_balance, self._native_currency
-            ),
+            ATTR_NATIVE_BALANCE: f"{self._native_balance} {self._native_currency}",
         }
 
     def update(self):
diff --git a/homeassistant/components/configurator/__init__.py b/homeassistant/components/configurator/__init__.py
index 4d79b13355c..e1e6181d8ca 100644
--- a/homeassistant/components/configurator/__init__.py
+++ b/homeassistant/components/configurator/__init__.py
@@ -237,7 +237,7 @@ class Configurator:
     def _generate_unique_id(self):
         """Generate a unique configurator ID."""
         self._cur_id += 1
-        return "{}-{}".format(id(self), self._cur_id)
+        return f"{id(self)}-{self._cur_id}"
 
     def _validate_request_id(self, request_id):
         """Validate that the request belongs to this instance."""
diff --git a/homeassistant/components/daikin/sensor.py b/homeassistant/components/daikin/sensor.py
index f83566e66e8..e3e2e6a0f27 100644
--- a/homeassistant/components/daikin/sensor.py
+++ b/homeassistant/components/daikin/sensor.py
@@ -47,9 +47,9 @@ class DaikinClimateSensor(Entity):
         self._api = api
         self._sensor = SENSOR_TYPES.get(monitored_state)
         if name is None:
-            name = "{} {}".format(self._sensor[CONF_NAME], api.name)
+            name = f"{self._sensor[CONF_NAME]} {api.name}"
 
-        self._name = "{} {}".format(name, monitored_state.replace("_", " "))
+        self._name = f"{name} {monitored_state.replace('_', ' ')}"
         self._device_attribute = monitored_state
 
         if self._sensor[CONF_TYPE] == SENSOR_TYPE_TEMPERATURE:
diff --git a/homeassistant/components/daikin/switch.py b/homeassistant/components/daikin/switch.py
index 4d3b0d3eade..e22c0b04995 100644
--- a/homeassistant/components/daikin/switch.py
+++ b/homeassistant/components/daikin/switch.py
@@ -54,7 +54,7 @@ class DaikinZoneSwitch(ToggleEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "{} {}".format(self._api.name, self._api.device.zones[self._zone_id][0])
+        return f"{self._api.name} {self._api.device.zones[self._zone_id][0]}"
 
     @property
     def is_on(self):
diff --git a/homeassistant/components/datadog/__init__.py b/homeassistant/components/datadog/__init__.py
index adb8bb1f95c..52cbe906402 100644
--- a/homeassistant/components/datadog/__init__.py
+++ b/homeassistant/components/datadog/__init__.py
@@ -61,8 +61,8 @@ def setup(hass, config):
             title="Home Assistant",
             text=f"%%% \n **{name}** {message} \n %%%",
             tags=[
-                "entity:{}".format(event.data.get("entity_id")),
-                "domain:{}".format(event.data.get("domain")),
+                f"entity:{event.data.get('entity_id')}",
+                f"domain:{event.data.get('domain')}",
             ],
         )
 
@@ -84,7 +84,7 @@ def setup(hass, config):
 
         for key, value in states.items():
             if isinstance(value, (float, int)):
-                attribute = "{}.{}".format(metric, key.replace(" ", "_"))
+                attribute = f"{metric}.{key.replace(' ', '_')}"
                 statsd.gauge(attribute, value, sample_rate=sample_rate, tags=tags)
 
                 _LOGGER.debug("Sent metric %s: %s (tags: %s)", attribute, value, tags)
diff --git a/homeassistant/components/deconz/const.py b/homeassistant/components/deconz/const.py
index 11dbd07e86a..cd125613f21 100644
--- a/homeassistant/components/deconz/const.py
+++ b/homeassistant/components/deconz/const.py
@@ -31,13 +31,6 @@ NEW_LIGHT = "lights"
 NEW_SCENE = "scenes"
 NEW_SENSOR = "sensors"
 
-NEW_DEVICE = {
-    NEW_GROUP: "deconz_new_group_{}",
-    NEW_LIGHT: "deconz_new_light_{}",
-    NEW_SCENE: "deconz_new_scene_{}",
-    NEW_SENSOR: "deconz_new_sensor_{}",
-}
-
 ATTR_DARK = "dark"
 ATTR_OFFSET = "offset"
 ATTR_ON = "on"
diff --git a/homeassistant/components/deconz/gateway.py b/homeassistant/components/deconz/gateway.py
index 0b69b82463c..b59c80a0dc8 100644
--- a/homeassistant/components/deconz/gateway.py
+++ b/homeassistant/components/deconz/gateway.py
@@ -19,8 +19,9 @@ from .const import (
     DEFAULT_ALLOW_DECONZ_GROUPS,
     DOMAIN,
     LOGGER,
-    NEW_DEVICE,
     NEW_GROUP,
+    NEW_LIGHT,
+    NEW_SCENE,
     NEW_SENSOR,
     SUPPORTED_PLATFORMS,
 )
@@ -186,7 +187,13 @@ class DeconzGateway:
     @callback
     def async_signal_new_device(self, device_type) -> str:
         """Gateway specific event to signal new device."""
-        return NEW_DEVICE[device_type].format(self.bridgeid)
+        new_device = {
+            NEW_GROUP: f"deconz_new_group_{self.bridgeid}",
+            NEW_LIGHT: f"deconz_new_light_{self.bridgeid}",
+            NEW_SCENE: f"deconz_new_scene_{self.bridgeid}",
+            NEW_SENSOR: f"deconz_new_sensor_{self.bridgeid}",
+        }
+        return new_device[device_type]
 
     @property
     def signal_remove_entity(self) -> str:
diff --git a/homeassistant/components/demo/__init__.py b/homeassistant/components/demo/__init__.py
index 3ea05ff6ae8..f1e6d3df74f 100644
--- a/homeassistant/components/demo/__init__.py
+++ b/homeassistant/components/demo/__init__.py
@@ -203,7 +203,7 @@ async def finish_setup(hass, config):
         {
             "script": {
                 "demo": {
-                    "alias": "Toggle {}".format(lights[0].split(".")[1]),
+                    "alias": f"Toggle {lights[0].split('.')[1]}",
                     "sequence": [
                         {
                             "service": "light.turn_off",
diff --git a/homeassistant/components/demo/air_quality.py b/homeassistant/components/demo/air_quality.py
index 9fe0f675d9d..656e22259e1 100644
--- a/homeassistant/components/demo/air_quality.py
+++ b/homeassistant/components/demo/air_quality.py
@@ -27,7 +27,7 @@ class DemoAirQuality(AirQualityEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "{} {}".format("Demo Air Quality", self._name)
+        return f"Demo Air Quality {self._name}"
 
     @property
     def should_poll(self):
diff --git a/homeassistant/components/demo/mailbox.py b/homeassistant/components/demo/mailbox.py
index ce9c5cc0ea6..860524dfd7c 100644
--- a/homeassistant/components/demo/mailbox.py
+++ b/homeassistant/components/demo/mailbox.py
@@ -26,7 +26,7 @@ class DemoMailbox(Mailbox):
         txt = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
         for idx in range(0, 10):
             msgtime = int(dt.as_timestamp(dt.utcnow()) - 3600 * 24 * (10 - idx))
-            msgtxt = "Message {}. {}".format(idx + 1, txt * (1 + idx * (idx % 2)))
+            msgtxt = f"Message {idx + 1}. {txt * (1 + idx * (idx % 2))}"
             msgsha = sha1(msgtxt.encode("utf-8")).hexdigest()
             msg = {
                 "info": {
diff --git a/homeassistant/components/demo/media_player.py b/homeassistant/components/demo/media_player.py
index 33fe4ee3647..7a8f4eb8fbe 100644
--- a/homeassistant/components/demo/media_player.py
+++ b/homeassistant/components/demo/media_player.py
@@ -48,7 +48,6 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
     await async_setup_platform(hass, {}, async_add_entities)
 
 
-YOUTUBE_COVER_URL_FORMAT = "https://img.youtube.com/vi/{}/hqdefault.jpg"
 SOUND_MODE_LIST = ["Dummy Music", "Dummy Movie"]
 DEFAULT_SOUND_MODE = "Dummy Music"
 
@@ -238,7 +237,7 @@ class DemoYoutubePlayer(AbstractDemoPlayer):
     @property
     def media_image_url(self):
         """Return the image url of current playing media."""
-        return YOUTUBE_COVER_URL_FORMAT.format(self.youtube_id)
+        return f"https://img.youtube.com/vi/{self.youtube_id}/hqdefault.jpg"
 
     @property
     def media_title(self):
diff --git a/homeassistant/components/demo/weather.py b/homeassistant/components/demo/weather.py
index 8cc1b2f95fd..b17c88fa828 100644
--- a/homeassistant/components/demo/weather.py
+++ b/homeassistant/components/demo/weather.py
@@ -106,7 +106,7 @@ class DemoWeather(WeatherEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "{} {}".format("Demo Weather", self._name)
+        return f"Demo Weather {self._name}"
 
     @property
     def should_poll(self):
diff --git a/homeassistant/components/deutsche_bahn/sensor.py b/homeassistant/components/deutsche_bahn/sensor.py
index 204518b2ce3..fd7496b1316 100644
--- a/homeassistant/components/deutsche_bahn/sensor.py
+++ b/homeassistant/components/deutsche_bahn/sensor.py
@@ -82,7 +82,7 @@ class DeutscheBahnSensor(Entity):
         self.data.update()
         self._state = self.data.connections[0].get("departure", "Unknown")
         if self.data.connections[0].get("delay", 0) != 0:
-            self._state += " + {}".format(self.data.connections[0]["delay"])
+            self._state += f" + {self.data.connections[0]['delay']}"
 
 
 class SchieneData:
diff --git a/homeassistant/components/device_tracker/const.py b/homeassistant/components/device_tracker/const.py
index 1778a87b36a..06313deccb6 100644
--- a/homeassistant/components/device_tracker/const.py
+++ b/homeassistant/components/device_tracker/const.py
@@ -5,7 +5,6 @@ import logging
 LOGGER = logging.getLogger(__package__)
 
 DOMAIN = "device_tracker"
-ENTITY_ID_FORMAT = DOMAIN + ".{}"
 
 PLATFORM_TYPE_LEGACY = "legacy"
 PLATFORM_TYPE_ENTITY = "entity_platform"
diff --git a/homeassistant/components/device_tracker/legacy.py b/homeassistant/components/device_tracker/legacy.py
index 08bbed12519..b4bfd506f27 100644
--- a/homeassistant/components/device_tracker/legacy.py
+++ b/homeassistant/components/device_tracker/legacy.py
@@ -45,7 +45,6 @@ from .const import (
     DEFAULT_CONSIDER_HOME,
     DEFAULT_TRACK_NEW,
     DOMAIN,
-    ENTITY_ID_FORMAT,
     LOGGER,
     SOURCE_TYPE_GPS,
 )
@@ -182,7 +181,7 @@ class DeviceTracker:
             return
 
         # Guard from calling see on entity registry entities.
-        entity_id = ENTITY_ID_FORMAT.format(dev_id)
+        entity_id = f"{DOMAIN}.{dev_id}"
         if registry.async_is_registered(entity_id):
             LOGGER.error(
                 "The see service is not supported for this entity %s", entity_id
@@ -308,7 +307,7 @@ class Device(RestoreEntity):
     ) -> None:
         """Initialize a device."""
         self.hass = hass
-        self.entity_id = ENTITY_ID_FORMAT.format(dev_id)
+        self.entity_id = f"{DOMAIN}.{dev_id}"
 
         # Timedelta object how long we consider a device home if it is not
         # detected anymore.
@@ -579,5 +578,7 @@ def get_gravatar_for_email(email: str):
     Async friendly.
     """
 
-    url = "https://www.gravatar.com/avatar/{}.jpg?s=80&d=wavatar"
-    return url.format(hashlib.md5(email.encode("utf-8").lower()).hexdigest())
+    return (
+        f"https://www.gravatar.com/avatar/"
+        f"{hashlib.md5(email.encode('utf-8').lower()).hexdigest()}.jpg?s=80&d=wavatar"
+    )
diff --git a/homeassistant/components/device_tracker/setup.py b/homeassistant/components/device_tracker/setup.py
index 42751b1a784..595e36ef07c 100644
--- a/homeassistant/components/device_tracker/setup.py
+++ b/homeassistant/components/device_tracker/setup.py
@@ -109,9 +109,7 @@ async def async_extract_config(hass, config):
             legacy.append(platform)
         else:
             raise ValueError(
-                "Unable to determine type for {}: {}".format(
-                    platform.name, platform.type
-                )
+                f"Unable to determine type for {platform.name}: {platform.type}"
             )
 
     return legacy
diff --git a/homeassistant/components/directv/media_player.py b/homeassistant/components/directv/media_player.py
index 603d0127fe6..0d593ab9a45 100644
--- a/homeassistant/components/directv/media_player.py
+++ b/homeassistant/components/directv/media_player.py
@@ -97,7 +97,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
 
     elif discovery_info:
         host = discovery_info.get("host")
-        name = "DirecTV_{}".format(discovery_info.get("serial", ""))
+        name = f"DirecTV_{discovery_info.get('serial', '')}"
 
         # Attempt to discover additional RVU units
         _LOGGER.debug("Doing discovery of DirecTV devices on %s", host)
@@ -219,9 +219,7 @@ class DirecTvDevice(MediaPlayerDevice):
                 else:
                     # If an error is received then only set to unavailable if
                     # this started at least 1 minute ago.
-                    log_message = "{}: Invalid status {} received".format(
-                        self.entity_id, self._current["status"]["code"]
-                    )
+                    log_message = f"{self.entity_id}: Invalid status {self._current['status']['code']} received"
                     if self._check_state_available():
                         _LOGGER.debug(log_message)
                     else:
@@ -370,7 +368,7 @@ class DirecTvDevice(MediaPlayerDevice):
         if self._is_standby:
             return None
 
-        return "{} ({})".format(self._current["callsign"], self._current["major"])
+        return f"{self._current['callsign']} ({self._current['major']})"
 
     @property
     def source(self):
diff --git a/homeassistant/components/dlib_face_detect/image_processing.py b/homeassistant/components/dlib_face_detect/image_processing.py
index 430878ca44f..9e56668eb3e 100644
--- a/homeassistant/components/dlib_face_detect/image_processing.py
+++ b/homeassistant/components/dlib_face_detect/image_processing.py
@@ -45,7 +45,7 @@ class DlibFaceDetectEntity(ImageProcessingFaceEntity):
         if name:
             self._name = name
         else:
-            self._name = "Dlib Face {0}".format(split_entity_id(camera_entity)[1])
+            self._name = f"Dlib Face {split_entity_id(camera_entity)[1]}"
 
     @property
     def camera_entity(self):
diff --git a/homeassistant/components/dlib_face_identify/image_processing.py b/homeassistant/components/dlib_face_identify/image_processing.py
index d6fbf106b0c..32c2aa5868c 100644
--- a/homeassistant/components/dlib_face_identify/image_processing.py
+++ b/homeassistant/components/dlib_face_identify/image_processing.py
@@ -59,7 +59,7 @@ class DlibFaceIdentifyEntity(ImageProcessingFaceEntity):
         if name:
             self._name = name
         else:
-            self._name = "Dlib Face {0}".format(split_entity_id(camera_entity)[1])
+            self._name = f"Dlib Face {split_entity_id(camera_entity)[1]}"
 
         self._faces = {}
         for face_name, face_file in faces.items():
diff --git a/homeassistant/components/doorbird/__init__.py b/homeassistant/components/doorbird/__init__.py
index d82e27f0f9a..049681a4aa6 100644
--- a/homeassistant/components/doorbird/__init__.py
+++ b/homeassistant/components/doorbird/__init__.py
@@ -66,7 +66,7 @@ def setup(hass, config):
         custom_url = doorstation_config.get(CONF_CUSTOM_URL)
         events = doorstation_config.get(CONF_EVENTS)
         token = doorstation_config.get(CONF_TOKEN)
-        name = doorstation_config.get(CONF_NAME) or "DoorBird {}".format(index + 1)
+        name = doorstation_config.get(CONF_NAME) or f"DoorBird {index + 1}"
 
         try:
             device = DoorBird(device_ip, username, password)
@@ -297,6 +297,6 @@ class DoorBirdRequestView(HomeAssistantView):
 
         hass.bus.async_fire(f"{DOMAIN}_{event}", event_data)
 
-        log_entry(hass, "Doorbird {}".format(event), "event was fired.", DOMAIN)
+        log_entry(hass, f"Doorbird {event}", "event was fired.", DOMAIN)
 
         return web.Response(status=200, text="OK")
diff --git a/homeassistant/components/doorbird/camera.py b/homeassistant/components/doorbird/camera.py
index d9a802f071f..4bf3a6e060f 100644
--- a/homeassistant/components/doorbird/camera.py
+++ b/homeassistant/components/doorbird/camera.py
@@ -12,9 +12,6 @@ import homeassistant.util.dt as dt_util
 
 from . import DOMAIN as DOORBIRD_DOMAIN
 
-_CAMERA_LAST_VISITOR = "{} Last Ring"
-_CAMERA_LAST_MOTION = "{} Last Motion"
-_CAMERA_LIVE = "{} Live"
 _LAST_VISITOR_INTERVAL = datetime.timedelta(minutes=1)
 _LAST_MOTION_INTERVAL = datetime.timedelta(minutes=1)
 _LIVE_INTERVAL = datetime.timedelta(seconds=1)
@@ -30,18 +27,18 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
             [
                 DoorBirdCamera(
                     device.live_image_url,
-                    _CAMERA_LIVE.format(doorstation.name),
+                    f"{doorstation.name} Live",
                     _LIVE_INTERVAL,
                     device.rtsp_live_video_url,
                 ),
                 DoorBirdCamera(
                     device.history_image_url(1, "doorbell"),
-                    _CAMERA_LAST_VISITOR.format(doorstation.name),
+                    f"{doorstation.name} Last Ring",
                     _LAST_VISITOR_INTERVAL,
                 ),
                 DoorBirdCamera(
                     device.history_image_url(1, "motionsensor"),
-                    _CAMERA_LAST_MOTION.format(doorstation.name),
+                    f"{doorstation.name} Last Motion",
                     _LAST_MOTION_INTERVAL,
                 ),
             ]
diff --git a/homeassistant/components/dovado/sensor.py b/homeassistant/components/dovado/sensor.py
index ab85c376469..5e3745b27ed 100644
--- a/homeassistant/components/dovado/sensor.py
+++ b/homeassistant/components/dovado/sensor.py
@@ -85,7 +85,7 @@ class DovadoSensor(Entity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "{} {}".format(self._data.name, SENSORS[self._sensor][1])
+        return f"{self._data.name} {SENSORS[self._sensor][1]}"
 
     @property
     def state(self):
diff --git a/homeassistant/components/dte_energy_bridge/sensor.py b/homeassistant/components/dte_energy_bridge/sensor.py
index aa822da0d6a..826f9cf5acb 100644
--- a/homeassistant/components/dte_energy_bridge/sensor.py
+++ b/homeassistant/components/dte_energy_bridge/sensor.py
@@ -47,11 +47,9 @@ class DteEnergyBridgeSensor(Entity):
         self._version = version
 
         if self._version == 1:
-            url_template = "http://{}/instantaneousdemand"
+            self._url = f"http://{ip_address}/instantaneousdemand"
         elif self._version == 2:
-            url_template = "http://{}:8888/zigbee/se/instantaneousdemand"
-
-        self._url = url_template.format(ip_address)
+            self._url = f"http://{ip_address}:8888/zigbee/se/instantaneousdemand"
 
         self._name = name
         self._unit_of_measurement = "kW"
diff --git a/homeassistant/components/dwd_weather_warnings/sensor.py b/homeassistant/components/dwd_weather_warnings/sensor.py
index af358343d8b..966ec407ce8 100644
--- a/homeassistant/components/dwd_weather_warnings/sensor.py
+++ b/homeassistant/components/dwd_weather_warnings/sensor.py
@@ -175,12 +175,7 @@ class DwdWeatherWarningsAPI:
 
     def __init__(self, region_name):
         """Initialize the data object."""
-        resource = "{}{}{}?{}".format(
-            "https://",
-            "www.dwd.de",
-            "/DWD/warnungen/warnapp_landkreise/json/warnings.json",
-            "jsonp=loadWarnings",
-        )
+        resource = "https://www.dwd.de/DWD/warnungen/warnapp_landkreise/json/warnings.json?jsonp=loadWarnings"
 
         # a User-Agent is necessary for this rest api endpoint (#29496)
         headers = {"User-Agent": HA_USER_AGENT}
diff --git a/homeassistant/components/dyson/climate.py b/homeassistant/components/dyson/climate.py
index df97358d550..f4e23b01622 100644
--- a/homeassistant/components/dyson/climate.py
+++ b/homeassistant/components/dyson/climate.py
@@ -89,7 +89,7 @@ class DysonPureHotCoolLinkDevice(ClimateDevice):
         if self._device.environmental_state:
             temperature_kelvin = self._device.environmental_state.temperature
             if temperature_kelvin != 0:
-                self._current_temp = float("{0:.1f}".format(temperature_kelvin - 273))
+                self._current_temp = float(f"{(temperature_kelvin - 273):.1f}")
         return self._current_temp
 
     @property
diff --git a/homeassistant/components/dyson/fan.py b/homeassistant/components/dyson/fan.py
index 4ec23921c03..8613ab3e7af 100644
--- a/homeassistant/components/dyson/fan.py
+++ b/homeassistant/components/dyson/fan.py
@@ -216,7 +216,7 @@ class DysonPureCoolLinkDevice(FanEntity):
         if speed == FanSpeed.FAN_SPEED_AUTO.value:
             self._device.set_configuration(fan_mode=FanMode.AUTO)
         else:
-            fan_speed = FanSpeed("{0:04d}".format(int(speed)))
+            fan_speed = FanSpeed(f"{int(speed):04d}")
             self._device.set_configuration(fan_mode=FanMode.FAN, fan_speed=fan_speed)
 
     def turn_on(self, speed: str = None, **kwargs) -> None:
@@ -226,7 +226,7 @@ class DysonPureCoolLinkDevice(FanEntity):
             if speed == FanSpeed.FAN_SPEED_AUTO.value:
                 self._device.set_configuration(fan_mode=FanMode.AUTO)
             else:
-                fan_speed = FanSpeed("{0:04d}".format(int(speed)))
+                fan_speed = FanSpeed(f"{int(speed):04d}")
                 self._device.set_configuration(
                     fan_mode=FanMode.FAN, fan_speed=fan_speed
                 )
@@ -386,7 +386,7 @@ class DysonPureCoolDevice(FanEntity):
         """Set the exact speed of the purecool fan."""
         _LOGGER.debug("Set exact speed for fan %s", self.name)
 
-        fan_speed = FanSpeed("{0:04d}".format(int(speed)))
+        fan_speed = FanSpeed(f"{int(speed):04d}")
         self._device.set_fan_speed(fan_speed)
 
     def oscillate(self, oscillating: bool) -> None:
diff --git a/homeassistant/components/dyson/sensor.py b/homeassistant/components/dyson/sensor.py
index 870086e7550..c7f61422a2e 100644
--- a/homeassistant/components/dyson/sensor.py
+++ b/homeassistant/components/dyson/sensor.py
@@ -43,9 +43,9 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     device_ids = [device.unique_id for device in hass.data[DYSON_SENSOR_DEVICES]]
     for device in hass.data[DYSON_DEVICES]:
         if isinstance(device, DysonPureCool):
-            if "{}-{}".format(device.serial, "temperature") not in device_ids:
+            if f"{device.serial}-temperature" not in device_ids:
                 devices.append(DysonTemperatureSensor(device, unit))
-            if "{}-{}".format(device.serial, "humidity") not in device_ids:
+            if f"{device.serial}-humidity" not in device_ids:
                 devices.append(DysonHumiditySensor(device))
         elif isinstance(device, DysonPureCoolLink):
             devices.append(DysonFilterLifeSensor(device))
@@ -173,8 +173,8 @@ class DysonTemperatureSensor(DysonSensor):
             if temperature_kelvin == 0:
                 return STATE_OFF
             if self._unit == TEMP_CELSIUS:
-                return float("{0:.1f}".format(temperature_kelvin - 273.15))
-            return float("{0:.1f}".format(temperature_kelvin * 9 / 5 - 459.67))
+                return float(f"{(temperature_kelvin - 273.15):.1f}")
+            return float(f"{(temperature_kelvin * 9 / 5 - 459.67):.1f}")
         return None
 
     @property
diff --git a/homeassistant/components/ecobee/sensor.py b/homeassistant/components/ecobee/sensor.py
index c2c34d148e3..ca3e7732e1b 100644
--- a/homeassistant/components/ecobee/sensor.py
+++ b/homeassistant/components/ecobee/sensor.py
@@ -37,7 +37,7 @@ class EcobeeSensor(Entity):
     def __init__(self, data, sensor_name, sensor_type, sensor_index):
         """Initialize the sensor."""
         self.data = data
-        self._name = "{} {}".format(sensor_name, SENSOR_TYPES[sensor_type][0])
+        self._name = f"{sensor_name} {SENSOR_TYPES[sensor_type][0]}"
         self.sensor_name = sensor_name
         self.type = sensor_type
         self.index = sensor_index
diff --git a/homeassistant/components/ecovacs/vacuum.py b/homeassistant/components/ecovacs/vacuum.py
index a74fdaa21ba..806c0b41285 100644
--- a/homeassistant/components/ecovacs/vacuum.py
+++ b/homeassistant/components/ecovacs/vacuum.py
@@ -56,10 +56,10 @@ class EcovacsVacuum(VacuumDevice):
         self.device = device
         self.device.connect_and_wait_until_ready()
         if self.device.vacuum.get("nick", None) is not None:
-            self._name = "{}".format(self.device.vacuum["nick"])
+            self._name = str(self.device.vacuum["nick"])
         else:
             # In case there is no nickname defined, use the device id
-            self._name = "{}".format(self.device.vacuum["did"])
+            self._name = str(format(self.device.vacuum["did"]))
 
         self._fan_speed = None
         self._error = None
diff --git a/homeassistant/components/efergy/sensor.py b/homeassistant/components/efergy/sensor.py
index 3be962fea2f..8c16317beda 100644
--- a/homeassistant/components/efergy/sensor.py
+++ b/homeassistant/components/efergy/sensor.py
@@ -63,9 +63,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     dev = []
     for variable in config[CONF_MONITORED_VARIABLES]:
         if variable[CONF_SENSOR_TYPE] == CONF_CURRENT_VALUES:
-            url_string = "{}getCurrentValuesSummary?token={}".format(
-                _RESOURCE, app_token
-            )
+            url_string = f"{_RESOURCE}getCurrentValuesSummary?token={app_token}"
             response = requests.get(url_string, timeout=10)
             for sensor in response.json():
                 sid = sensor["sid"]
@@ -136,9 +134,7 @@ class EfergySensor(Entity):
                 response = requests.get(url_string, timeout=10)
                 self._state = response.json()["reading"]
             elif self.type == "amount":
-                url_string = "{}getEnergy?token={}&offset={}&period={}".format(
-                    _RESOURCE, self.app_token, self.utc_offset, self.period
-                )
+                url_string = f"{_RESOURCE}getEnergy?token={self.app_token}&offset={self.utc_offset}&period={self.period}"
                 response = requests.get(url_string, timeout=10)
                 self._state = response.json()["sum"]
             elif self.type == "budget":
@@ -146,14 +142,12 @@ class EfergySensor(Entity):
                 response = requests.get(url_string, timeout=10)
                 self._state = response.json()["status"]
             elif self.type == "cost":
-                url_string = "{}getCost?token={}&offset={}&period={}".format(
-                    _RESOURCE, self.app_token, self.utc_offset, self.period
-                )
+                url_string = f"{_RESOURCE}getCost?token={self.app_token}&offset={self.utc_offset}&period={self.period}"
                 response = requests.get(url_string, timeout=10)
                 self._state = response.json()["sum"]
             elif self.type == "current_values":
-                url_string = "{}getCurrentValuesSummary?token={}".format(
-                    _RESOURCE, self.app_token
+                url_string = (
+                    f"{_RESOURCE}getCurrentValuesSummary?token={self.app_token}"
                 )
                 response = requests.get(url_string, timeout=10)
                 for sensor in response.json():
diff --git a/homeassistant/components/elkm1/__init__.py b/homeassistant/components/elkm1/__init__.py
index 67b84c4f3bf..2acb8030cf1 100644
--- a/homeassistant/components/elkm1/__init__.py
+++ b/homeassistant/components/elkm1/__init__.py
@@ -257,9 +257,7 @@ class ElkEntity(Entity):
             uid_start = f"elkm1m_{self._prefix}"
         else:
             uid_start = "elkm1"
-        self._unique_id = "{uid_start}_{name}".format(
-            uid_start=uid_start, name=self._element.default_name("_")
-        ).lower()
+        self._unique_id = f"{uid_start}_{self._element.default_name('_')}".lower()
 
     @property
     def name(self):
diff --git a/homeassistant/components/elkm1/sensor.py b/homeassistant/components/elkm1/sensor.py
index 3ed5356f4de..df29e1cda7e 100644
--- a/homeassistant/components/elkm1/sensor.py
+++ b/homeassistant/components/elkm1/sensor.py
@@ -178,7 +178,7 @@ class ElkZone(ElkSensor):
             ZoneType.PHONE_KEY.value: "phone-classic",
             ZoneType.INTERCOM_KEY.value: "deskphone",
         }
-        return "mdi:{}".format(zone_icons.get(self._element.definition, "alarm-bell"))
+        return f"mdi:{zone_icons.get(self._element.definition, 'alarm-bell')}"
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/elv/switch.py b/homeassistant/components/elv/switch.py
index a77d21cf173..d867d286f50 100644
--- a/homeassistant/components/elv/switch.py
+++ b/homeassistant/components/elv/switch.py
@@ -81,12 +81,12 @@ class SmartPlugSwitch(SwitchDevice):
     def update(self):
         """Update the PCA switch's state."""
         try:
-            self._emeter_params[ATTR_CURRENT_POWER_W] = "{:.1f}".format(
-                self._pca.get_current_power(self._device_id)
-            )
-            self._emeter_params[ATTR_TOTAL_ENERGY_KWH] = "{:.2f}".format(
-                self._pca.get_total_consumption(self._device_id)
-            )
+            self._emeter_params[
+                ATTR_CURRENT_POWER_W
+            ] = f"{self._pca.get_current_power(self._device_id):.1f}"
+            self._emeter_params[
+                ATTR_TOTAL_ENERGY_KWH
+            ] = f"{self._pca.get_total_consumption(self._device_id):.2f}"
 
             self._available = True
             self._state = self._pca.get_state(self._device_id)
diff --git a/homeassistant/components/emoncms/sensor.py b/homeassistant/components/emoncms/sensor.py
index f956d3a7295..4f214d697f3 100644
--- a/homeassistant/components/emoncms/sensor.py
+++ b/homeassistant/components/emoncms/sensor.py
@@ -64,9 +64,7 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
 
 def get_id(sensorid, feedtag, feedname, feedid, feeduserid):
     """Return unique identifier for feed / sensor."""
-    return "emoncms{}_{}_{}_{}_{}".format(
-        sensorid, feedtag, feedname, feedid, feeduserid
-    )
+    return f"emoncms{sensorid}_{feedtag}_{feedname}_{feedid}_{feeduserid}"
 
 
 def setup_platform(hass, config, add_entities, discovery_info=None):
@@ -134,7 +132,7 @@ class EmonCmsSensor(Entity):
             # ID if there's only one.
             id_for_name = "" if str(sensorid) == "1" else sensorid
             # Use the feed name assigned in EmonCMS or fall back to the feed ID
-            feed_name = elem.get("name") or "Feed {}".format(elem["id"])
+            feed_name = elem.get("name") or f"Feed {elem['id']}"
             self._name = f"EmonCMS{id_for_name} {feed_name}"
         else:
             self._name = name
diff --git a/homeassistant/components/emulated_hue/hue_api.py b/homeassistant/components/emulated_hue/hue_api.py
index e9e7114074a..9a2d624a55f 100644
--- a/homeassistant/components/emulated_hue/hue_api.py
+++ b/homeassistant/components/emulated_hue/hue_api.py
@@ -617,16 +617,7 @@ def entity_to_json(config, entity):
     """Convert an entity to its Hue bridge JSON representation."""
     entity_features = entity.attributes.get(ATTR_SUPPORTED_FEATURES, 0)
     unique_id = hashlib.md5(entity.entity_id.encode()).hexdigest()
-    unique_id = "00:{}:{}:{}:{}:{}:{}:{}-{}".format(
-        unique_id[0:2],
-        unique_id[2:4],
-        unique_id[4:6],
-        unique_id[6:8],
-        unique_id[8:10],
-        unique_id[10:12],
-        unique_id[12:14],
-        unique_id[14:16],
-    )
+    unique_id = f"00:{unique_id[0:2]}:{unique_id[2:4]}:{unique_id[4:6]}:{unique_id[6:8]}:{unique_id[8:10]}:{unique_id[10:12]}:{unique_id[12:14]}-{unique_id[14:16]}"
 
     state = get_entity_state(config, entity)
 
diff --git a/homeassistant/components/emulated_hue/upnp.py b/homeassistant/components/emulated_hue/upnp.py
index da9b4e23fe2..0ee336de670 100644
--- a/homeassistant/components/emulated_hue/upnp.py
+++ b/homeassistant/components/emulated_hue/upnp.py
@@ -26,16 +26,16 @@ class DescriptionXmlView(HomeAssistantView):
     @core.callback
     def get(self, request):
         """Handle a GET request."""
-        xml_template = """<?xml version="1.0" encoding="UTF-8" ?>
+        resp_text = f"""<?xml version="1.0" encoding="UTF-8" ?>
 <root xmlns="urn:schemas-upnp-org:device-1-0">
 <specVersion>
 <major>1</major>
 <minor>0</minor>
 </specVersion>
-<URLBase>http://{0}:{1}/</URLBase>
+<URLBase>http://{self.config.advertise_ip}:{self.config.advertise_port}/</URLBase>
 <device>
 <deviceType>urn:schemas-upnp-org:device:Basic:1</deviceType>
-<friendlyName>Home Assistant Bridge ({0})</friendlyName>
+<friendlyName>Home Assistant Bridge ({self.config.advertise_ip})</friendlyName>
 <manufacturer>Royal Philips Electronics</manufacturer>
 <manufacturerURL>http://www.philips.com</manufacturerURL>
 <modelDescription>Philips hue Personal Wireless Lighting</modelDescription>
@@ -48,10 +48,6 @@ class DescriptionXmlView(HomeAssistantView):
 </root>
 """
 
-        resp_text = xml_template.format(
-            self.config.advertise_ip, self.config.advertise_port
-        )
-
         return web.Response(text=resp_text, content_type="text/xml")
 
 
@@ -77,10 +73,10 @@ class UPNPResponderThread(threading.Thread):
 
         # Note that the double newline at the end of
         # this string is required per the SSDP spec
-        resp_template = """HTTP/1.1 200 OK
+        resp_template = f"""HTTP/1.1 200 OK
 CACHE-CONTROL: max-age=60
 EXT:
-LOCATION: http://{0}:{1}/description.xml
+LOCATION: http://{advertise_ip}:{advertise_port}/description.xml
 SERVER: FreeRTOS/6.0.5, UPnP/1.0, IpBridge/0.1
 hue-bridgeid: 1234
 ST: urn:schemas-upnp-org:device:basic:1
@@ -88,11 +84,7 @@ USN: uuid:Socket-1_0-221438K0100073::urn:schemas-upnp-org:device:basic:1
 
 """
 
-        self.upnp_response = (
-            resp_template.format(advertise_ip, advertise_port)
-            .replace("\n", "\r\n")
-            .encode("utf-8")
-        )
+        self.upnp_response = resp_template.replace("\n", "\r\n").encode("utf-8")
 
     def run(self):
         """Run the server."""
diff --git a/homeassistant/components/emulated_roku/config_flow.py b/homeassistant/components/emulated_roku/config_flow.py
index 0a6d54693ef..3e363e060c2 100644
--- a/homeassistant/components/emulated_roku/config_flow.py
+++ b/homeassistant/components/emulated_roku/config_flow.py
@@ -38,7 +38,7 @@ class EmulatedRokuFlowHandler(config_entries.ConfigFlow):
         servers_num = len(configured_servers(self.hass))
 
         if servers_num:
-            default_name = "{} {}".format(DEFAULT_NAME, servers_num + 1)
+            default_name = f"{DEFAULT_NAME} {servers_num + 1}"
             default_port = DEFAULT_PORT + servers_num
         else:
             default_name = DEFAULT_NAME
diff --git a/homeassistant/components/enocean/sensor.py b/homeassistant/components/enocean/sensor.py
index 59ca10da791..5cf908a33a1 100644
--- a/homeassistant/components/enocean/sensor.py
+++ b/homeassistant/components/enocean/sensor.py
@@ -111,9 +111,7 @@ class EnOceanSensor(enocean.EnOceanDevice):
         super().__init__(dev_id, dev_name)
         self._sensor_type = sensor_type
         self._device_class = SENSOR_TYPES[self._sensor_type]["class"]
-        self._dev_name = "{} {}".format(
-            SENSOR_TYPES[self._sensor_type]["name"], dev_name
-        )
+        self._dev_name = f"{SENSOR_TYPES[self._sensor_type]['name']} {dev_name}"
         self._unit_of_measurement = SENSOR_TYPES[self._sensor_type]["unit"]
         self._icon = SENSOR_TYPES[self._sensor_type]["icon"]
         self._state = None
diff --git a/homeassistant/components/entur_public_transport/sensor.py b/homeassistant/components/entur_public_transport/sensor.py
index 156a0e601b4..0425accd06b 100644
--- a/homeassistant/components/entur_public_transport/sensor.py
+++ b/homeassistant/components/entur_public_transport/sensor.py
@@ -120,7 +120,7 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
     entities = []
     for place in data.all_stop_places_quays():
         try:
-            given_name = "{} {}".format(name, data.get_stop_info(place).name)
+            given_name = f"{name} {data.get_stop_info(place).name}"
         except KeyError:
             given_name = f"{name} {place}"
 
@@ -231,9 +231,9 @@ class EnturPublicTransportSensor(Entity):
         self._attributes[ATTR_NEXT_UP_AT] = calls[1].expected_departure_time.strftime(
             "%H:%M"
         )
-        self._attributes[ATTR_NEXT_UP_IN] = "{} min".format(
-            due_in_minutes(calls[1].expected_departure_time)
-        )
+        self._attributes[
+            ATTR_NEXT_UP_IN
+        ] = f"{due_in_minutes(calls[1].expected_departure_time)} min"
         self._attributes[ATTR_NEXT_UP_REALTIME] = calls[1].is_realtime
         self._attributes[ATTR_NEXT_UP_DELAY] = calls[1].delay_in_min
 
@@ -242,8 +242,7 @@ class EnturPublicTransportSensor(Entity):
 
         for i, call in enumerate(calls[2:]):
             key_name = "departure_#" + str(i + 3)
-            self._attributes[key_name] = "{}{} {}".format(
-                "" if bool(call.is_realtime) else "ca. ",
-                call.expected_departure_time.strftime("%H:%M"),
-                call.front_display,
+            self._attributes[key_name] = (
+                f"{'' if bool(call.is_realtime) else 'ca. '}"
+                f"{call.expected_departure_time.strftime('%H:%M')} {call.front_display}"
             )
diff --git a/homeassistant/components/environment_canada/sensor.py b/homeassistant/components/environment_canada/sensor.py
index f32de07e4fb..601a7f2ba36 100644
--- a/homeassistant/components/environment_canada/sensor.py
+++ b/homeassistant/components/environment_canada/sensor.py
@@ -113,7 +113,7 @@ class ECSensor(Entity):
         metadata = self.ec_data.metadata
         sensor_data = conditions.get(self.sensor_type)
 
-        self._unique_id = "{}-{}".format(metadata["location"], self.sensor_type)
+        self._unique_id = f"{metadata['location']}-{self.sensor_type}"
         self._attr = {}
         self._name = sensor_data.get("label")
         value = sensor_data.get("value")
diff --git a/homeassistant/components/esphome/__init__.py b/homeassistant/components/esphome/__init__.py
index cabba95ea7e..9fbe3eff822 100644
--- a/homeassistant/components/esphome/__init__.py
+++ b/homeassistant/components/esphome/__init__.py
@@ -39,20 +39,11 @@ from homeassistant.helpers.typing import ConfigType, HomeAssistantType
 
 # Import config flow so that it's added to the registry
 from .config_flow import EsphomeFlowHandler  # noqa: F401
-from .entry_data import (
-    DATA_KEY,
-    DISPATCHER_ON_DEVICE_UPDATE,
-    DISPATCHER_ON_LIST,
-    DISPATCHER_ON_STATE,
-    DISPATCHER_REMOVE_ENTITY,
-    DISPATCHER_UPDATE_ENTITY,
-    RuntimeEntryData,
-)
+from .entry_data import DATA_KEY, RuntimeEntryData
 
 DOMAIN = "esphome"
 _LOGGER = logging.getLogger(__name__)
 
-STORAGE_KEY = "esphome.{}"
 STORAGE_VERSION = 1
 
 # No config schema - only configuration entry
@@ -85,7 +76,7 @@ async def async_setup_entry(hass: HomeAssistantType, entry: ConfigEntry) -> bool
 
     # Store client in per-config-entry hass.data
     store = Store(
-        hass, STORAGE_VERSION, STORAGE_KEY.format(entry.entry_id), encoder=JSONEncoder
+        hass, STORAGE_VERSION, f"esphome.{entry.entry_id}", encoder=JSONEncoder
     )
     entry_data = hass.data[DATA_KEY][entry.entry_id] = RuntimeEntryData(
         client=cli, entry_id=entry.entry_id, store=store
@@ -403,7 +394,7 @@ async def platform_async_setup_entry(
         # Add entities to Home Assistant
         async_add_entities(add_entities)
 
-    signal = DISPATCHER_ON_LIST.format(entry_id=entry.entry_id)
+    signal = f"esphome_{entry.entry_id}_on_list"
     entry_data.cleanup_callbacks.append(
         async_dispatcher_connect(hass, signal, async_list_entities)
     )
@@ -416,7 +407,7 @@ async def platform_async_setup_entry(
         entry_data.state[component_key][state.key] = state
         entry_data.async_update_entity(hass, component_key, state.key)
 
-    signal = DISPATCHER_ON_STATE.format(entry_id=entry.entry_id)
+    signal = f"esphome_{entry.entry_id}_on_state"
     entry_data.cleanup_callbacks.append(
         async_dispatcher_connect(hass, signal, async_entity_state)
     )
@@ -490,21 +481,29 @@ class EsphomeEntity(Entity):
         self._remove_callbacks.append(
             async_dispatcher_connect(
                 self.hass,
-                DISPATCHER_UPDATE_ENTITY.format(**kwargs),
+                (
+                    f"esphome_{kwargs.get('entry_id')}"
+                    f"_update_{kwargs.get('component_key')}_{kwargs.get('key')}"
+                ),
                 self._on_state_update,
             )
         )
 
         self._remove_callbacks.append(
             async_dispatcher_connect(
-                self.hass, DISPATCHER_REMOVE_ENTITY.format(**kwargs), self.async_remove
+                self.hass,
+                (
+                    f"esphome_{kwargs.get('entry_id')}_remove_"
+                    f"{kwargs.get('component_key')}_{kwargs.get('key')}"
+                ),
+                self.async_remove,
             )
         )
 
         self._remove_callbacks.append(
             async_dispatcher_connect(
                 self.hass,
-                DISPATCHER_ON_DEVICE_UPDATE.format(**kwargs),
+                f"esphome_{kwargs.get('entry_id')}_on_device_update",
                 self._on_device_update,
             )
         )
diff --git a/homeassistant/components/esphome/entry_data.py b/homeassistant/components/esphome/entry_data.py
index c56760e952f..d8453c974f6 100644
--- a/homeassistant/components/esphome/entry_data.py
+++ b/homeassistant/components/esphome/entry_data.py
@@ -27,11 +27,6 @@ from homeassistant.helpers.storage import Store
 from homeassistant.helpers.typing import HomeAssistantType
 
 DATA_KEY = "esphome"
-DISPATCHER_UPDATE_ENTITY = "esphome_{entry_id}_update_{component_key}_{key}"
-DISPATCHER_REMOVE_ENTITY = "esphome_{entry_id}_remove_{component_key}_{key}"
-DISPATCHER_ON_LIST = "esphome_{entry_id}_on_list"
-DISPATCHER_ON_DEVICE_UPDATE = "esphome_{entry_id}_on_device_update"
-DISPATCHER_ON_STATE = "esphome_{entry_id}_on_state"
 
 # Mapping from ESPHome info type to HA platform
 INFO_TYPE_TO_PLATFORM = {
@@ -77,9 +72,7 @@ class RuntimeEntryData:
         self, hass: HomeAssistantType, component_key: str, key: int
     ) -> None:
         """Schedule the update of an entity."""
-        signal = DISPATCHER_UPDATE_ENTITY.format(
-            entry_id=self.entry_id, component_key=component_key, key=key
-        )
+        signal = f"esphome_{self.entry_id}_update_{component_key}_{key}"
         async_dispatcher_send(hass, signal)
 
     @callback
@@ -87,9 +80,7 @@ class RuntimeEntryData:
         self, hass: HomeAssistantType, component_key: str, key: int
     ) -> None:
         """Schedule the removal of an entity."""
-        signal = DISPATCHER_REMOVE_ENTITY.format(
-            entry_id=self.entry_id, component_key=component_key, key=key
-        )
+        signal = f"esphome_{self.entry_id}_remove_{component_key}_{key}"
         async_dispatcher_send(hass, signal)
 
     async def _ensure_platforms_loaded(
@@ -120,19 +111,19 @@ class RuntimeEntryData:
         await self._ensure_platforms_loaded(hass, entry, needed_platforms)
 
         # Then send dispatcher event
-        signal = DISPATCHER_ON_LIST.format(entry_id=self.entry_id)
+        signal = f"esphome_{self.entry_id}_on_list"
         async_dispatcher_send(hass, signal, infos)
 
     @callback
     def async_update_state(self, hass: HomeAssistantType, state: EntityState) -> None:
         """Distribute an update of state information to all platforms."""
-        signal = DISPATCHER_ON_STATE.format(entry_id=self.entry_id)
+        signal = f"esphome_{self.entry_id}_on_state"
         async_dispatcher_send(hass, signal, state)
 
     @callback
     def async_update_device_state(self, hass: HomeAssistantType) -> None:
         """Distribute an update of a core device state like availability."""
-        signal = DISPATCHER_ON_DEVICE_UPDATE.format(entry_id=self.entry_id)
+        signal = f"esphome_{self.entry_id}_on_device_update"
         async_dispatcher_send(hass, signal)
 
     async def async_load_from_store(self) -> Tuple[List[EntityInfo], List[UserService]]:
diff --git a/homeassistant/components/esphome/sensor.py b/homeassistant/components/esphome/sensor.py
index e50991af6c1..0856f270710 100644
--- a/homeassistant/components/esphome/sensor.py
+++ b/homeassistant/components/esphome/sensor.py
@@ -69,9 +69,7 @@ class EsphomeSensor(EsphomeEntity):
             return None
         if self._state.missing_state:
             return None
-        return "{:.{prec}f}".format(
-            self._state.state, prec=self._static_info.accuracy_decimals
-        )
+        return f"{self._state.state:.{self._static_info.accuracy_decimals}f}"
 
     @property
     def unit_of_measurement(self) -> str:
diff --git a/homeassistant/components/everlights/light.py b/homeassistant/components/everlights/light.py
index f7fa9deffa0..da9d5b88ae0 100644
--- a/homeassistant/components/everlights/light.py
+++ b/homeassistant/components/everlights/light.py
@@ -32,8 +32,6 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
     {vol.Required(CONF_HOSTS): vol.All(cv.ensure_list, [cv.string])}
 )
 
-NAME_FORMAT = "EverLights {} Zone {}"
-
 
 def color_rgb_to_int(red: int, green: int, blue: int) -> int:
     """Return a RGB color as an integer."""
@@ -96,7 +94,7 @@ class EverLightsLight(Light):
     @property
     def name(self):
         """Return the name of the device."""
-        return NAME_FORMAT.format(self._mac, self._channel)
+        return f"EverLights {self._mac} Zone {self._channel}"
 
     @property
     def is_on(self):
diff --git a/homeassistant/components/life360/device_tracker.py b/homeassistant/components/life360/device_tracker.py
index b7b0415a1b3..6f4255735e0 100644
--- a/homeassistant/components/life360/device_tracker.py
+++ b/homeassistant/components/life360/device_tracker.py
@@ -5,9 +5,9 @@ import logging
 from life360 import Life360Error
 import voluptuous as vol
 
-from homeassistant.components.device_tracker import CONF_SCAN_INTERVAL
-from homeassistant.components.device_tracker.const import (
-    ENTITY_ID_FORMAT as DT_ENTITY_ID_FORMAT,
+from homeassistant.components.device_tracker import (
+    CONF_SCAN_INTERVAL,
+    DOMAIN as DEVICE_TRACKER_DOMAIN,
 )
 from homeassistant.components.zone import async_active_zone
 from homeassistant.const import (
@@ -180,14 +180,14 @@ class Life360Scanner:
             if overdue and not reported and now - self._started > EVENT_DELAY:
                 self._hass.bus.fire(
                     EVENT_UPDATE_OVERDUE,
-                    {ATTR_ENTITY_ID: DT_ENTITY_ID_FORMAT.format(dev_id)},
+                    {ATTR_ENTITY_ID: f"{DEVICE_TRACKER_DOMAIN}.{dev_id}"},
                 )
                 reported = True
             elif not overdue and reported:
                 self._hass.bus.fire(
                     EVENT_UPDATE_RESTORED,
                     {
-                        ATTR_ENTITY_ID: DT_ENTITY_ID_FORMAT.format(dev_id),
+                        ATTR_ENTITY_ID: f"{DEVICE_TRACKER_DOMAIN}.{dev_id}",
                         ATTR_WAIT: str(last_seen - (prev_seen or self._started)).split(
                             "."
                         )[0],
diff --git a/homeassistant/components/owntracks/device_tracker.py b/homeassistant/components/owntracks/device_tracker.py
index 00fa023d6c1..ed94ef0fa14 100644
--- a/homeassistant/components/owntracks/device_tracker.py
+++ b/homeassistant/components/owntracks/device_tracker.py
@@ -4,7 +4,7 @@ import logging
 from homeassistant.components.device_tracker.config_entry import TrackerEntity
 from homeassistant.components.device_tracker.const import (
     ATTR_SOURCE_TYPE,
-    ENTITY_ID_FORMAT,
+    DOMAIN,
     SOURCE_TYPE_GPS,
 )
 from homeassistant.const import (
@@ -68,7 +68,7 @@ class OwnTracksEntity(TrackerEntity, RestoreEntity):
         """Set up OwnTracks entity."""
         self._dev_id = dev_id
         self._data = data or {}
-        self.entity_id = ENTITY_ID_FORMAT.format(dev_id)
+        self.entity_id = f"{DOMAIN}.{dev_id}"
 
     @property
     def unique_id(self):
diff --git a/tests/components/device_sun_light_trigger/test_init.py b/tests/components/device_sun_light_trigger/test_init.py
index c8d0e334412..bc4d44e1b42 100644
--- a/tests/components/device_sun_light_trigger/test_init.py
+++ b/tests/components/device_sun_light_trigger/test_init.py
@@ -11,9 +11,7 @@ from homeassistant.components import (
     group,
     light,
 )
-from homeassistant.components.device_tracker.const import (
-    ENTITY_ID_FORMAT as DT_ENTITY_ID_FORMAT,
-)
+from homeassistant.components.device_tracker.const import DOMAIN
 from homeassistant.const import CONF_PLATFORM, STATE_HOME, STATE_NOT_HOME
 from homeassistant.setup import async_setup_component
 from homeassistant.util import dt as dt_util
@@ -122,7 +120,7 @@ async def test_lights_turn_on_when_coming_home_after_sun_set(hass, scanner):
             hass, device_sun_light_trigger.DOMAIN, {device_sun_light_trigger.DOMAIN: {}}
         )
 
-        hass.states.async_set(DT_ENTITY_ID_FORMAT.format("device_2"), STATE_HOME)
+        hass.states.async_set(f"{DOMAIN}.device_2", STATE_HOME)
 
         await hass.async_block_till_done()
 
@@ -133,8 +131,8 @@ async def test_lights_turn_on_when_coming_home_after_sun_set(hass, scanner):
 
 async def test_lights_turn_on_when_coming_home_after_sun_set_person(hass, scanner):
     """Test lights turn on when coming home after sun set."""
-    device_1 = DT_ENTITY_ID_FORMAT.format("device_1")
-    device_2 = DT_ENTITY_ID_FORMAT.format("device_2")
+    device_1 = f"{DOMAIN}.device_1"
+    device_2 = f"{DOMAIN}.device_2"
 
     test_time = datetime(2017, 4, 5, 3, 2, 3, tzinfo=dt_util.UTC)
     with patch("homeassistant.util.dt.utcnow", return_value=test_time):
diff --git a/tests/components/device_tracker/test_init.py b/tests/components/device_tracker/test_init.py
index 4d82f93a029..3ad9e741aae 100644
--- a/tests/components/device_tracker/test_init.py
+++ b/tests/components/device_tracker/test_init.py
@@ -57,7 +57,7 @@ def mock_yaml_devices(hass):
 
 async def test_is_on(hass):
     """Test is_on method."""
-    entity_id = const.ENTITY_ID_FORMAT.format("test")
+    entity_id = f"{const.DOMAIN}.test"
 
     hass.states.async_set(entity_id, STATE_HOME)
 
@@ -271,7 +271,7 @@ async def test_entity_attributes(hass, mock_device_tracker_conf):
     """Test the entity attributes."""
     devices = mock_device_tracker_conf
     dev_id = "test_entity"
-    entity_id = const.ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{const.DOMAIN}.{dev_id}"
     friendly_name = "Paulus"
     picture = "http://placehold.it/200x200"
     icon = "mdi:kettle"
@@ -303,7 +303,7 @@ async def test_device_hidden(hass, mock_device_tracker_conf):
     """Test hidden devices."""
     devices = mock_device_tracker_conf
     dev_id = "test_entity"
-    entity_id = const.ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{const.DOMAIN}.{dev_id}"
     device = legacy.Device(
         hass, timedelta(seconds=180), True, dev_id, None, hide_if_away=True
     )
@@ -350,7 +350,7 @@ async def test_see_service_guard_config_entry(hass, mock_device_tracker_conf):
     """Test the guard if the device is registered in the entity registry."""
     mock_entry = Mock()
     dev_id = "test"
-    entity_id = const.ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{const.DOMAIN}.{dev_id}"
     mock_registry(hass, {entity_id: mock_entry})
     devices = mock_device_tracker_conf
     assert await async_setup_component(hass, device_tracker.DOMAIN, TEST_PLATFORM)
diff --git a/tests/components/mqtt/test_device_tracker.py b/tests/components/mqtt/test_device_tracker.py
index f4324bd8634..aa6d3efc828 100644
--- a/tests/components/mqtt/test_device_tracker.py
+++ b/tests/components/mqtt/test_device_tracker.py
@@ -2,11 +2,7 @@
 from asynctest import patch
 import pytest
 
-from homeassistant.components import device_tracker
-from homeassistant.components.device_tracker.const import (
-    ENTITY_ID_FORMAT,
-    SOURCE_TYPE_BLUETOOTH,
-)
+from homeassistant.components.device_tracker.const import DOMAIN, SOURCE_TYPE_BLUETOOTH
 from homeassistant.const import CONF_PLATFORM, STATE_HOME, STATE_NOT_HOME
 from homeassistant.setup import async_setup_component
 
@@ -35,14 +31,7 @@ async def test_ensure_device_tracker_platform_validation(hass):
         dev_id = "paulus"
         topic = "/location/paulus"
         assert await async_setup_component(
-            hass,
-            device_tracker.DOMAIN,
-            {
-                device_tracker.DOMAIN: {
-                    CONF_PLATFORM: "mqtt",
-                    "devices": {dev_id: topic},
-                }
-            },
+            hass, DOMAIN, {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: topic}}}
         )
         assert mock_sp.call_count == 1
 
@@ -50,15 +39,13 @@ async def test_ensure_device_tracker_platform_validation(hass):
 async def test_new_message(hass, mock_device_tracker_conf):
     """Test new message."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     topic = "/location/paulus"
     location = "work"
 
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
-        hass,
-        device_tracker.DOMAIN,
-        {device_tracker.DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: topic}}},
+        hass, DOMAIN, {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: topic}}}
     )
     async_fire_mqtt_message(hass, topic, location)
     await hass.async_block_till_done()
@@ -68,7 +55,7 @@ async def test_new_message(hass, mock_device_tracker_conf):
 async def test_single_level_wildcard_topic(hass, mock_device_tracker_conf):
     """Test single level wildcard topic."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     subscription = "/location/+/paulus"
     topic = "/location/room/paulus"
     location = "work"
@@ -76,13 +63,8 @@ async def test_single_level_wildcard_topic(hass, mock_device_tracker_conf):
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
-        {
-            device_tracker.DOMAIN: {
-                CONF_PLATFORM: "mqtt",
-                "devices": {dev_id: subscription},
-            }
-        },
+        DOMAIN,
+        {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: subscription}}},
     )
     async_fire_mqtt_message(hass, topic, location)
     await hass.async_block_till_done()
@@ -92,7 +74,7 @@ async def test_single_level_wildcard_topic(hass, mock_device_tracker_conf):
 async def test_multi_level_wildcard_topic(hass, mock_device_tracker_conf):
     """Test multi level wildcard topic."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     subscription = "/location/#"
     topic = "/location/room/paulus"
     location = "work"
@@ -100,13 +82,8 @@ async def test_multi_level_wildcard_topic(hass, mock_device_tracker_conf):
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
-        {
-            device_tracker.DOMAIN: {
-                CONF_PLATFORM: "mqtt",
-                "devices": {dev_id: subscription},
-            }
-        },
+        DOMAIN,
+        {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: subscription}}},
     )
     async_fire_mqtt_message(hass, topic, location)
     await hass.async_block_till_done()
@@ -116,7 +93,7 @@ async def test_multi_level_wildcard_topic(hass, mock_device_tracker_conf):
 async def test_single_level_wildcard_topic_not_matching(hass, mock_device_tracker_conf):
     """Test not matching single level wildcard topic."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     subscription = "/location/+/paulus"
     topic = "/location/paulus"
     location = "work"
@@ -124,13 +101,8 @@ async def test_single_level_wildcard_topic_not_matching(hass, mock_device_tracke
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
-        {
-            device_tracker.DOMAIN: {
-                CONF_PLATFORM: "mqtt",
-                "devices": {dev_id: subscription},
-            }
-        },
+        DOMAIN,
+        {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: subscription}}},
     )
     async_fire_mqtt_message(hass, topic, location)
     await hass.async_block_till_done()
@@ -140,7 +112,7 @@ async def test_single_level_wildcard_topic_not_matching(hass, mock_device_tracke
 async def test_multi_level_wildcard_topic_not_matching(hass, mock_device_tracker_conf):
     """Test not matching multi level wildcard topic."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     subscription = "/location/#"
     topic = "/somewhere/room/paulus"
     location = "work"
@@ -148,13 +120,8 @@ async def test_multi_level_wildcard_topic_not_matching(hass, mock_device_tracker
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
-        {
-            device_tracker.DOMAIN: {
-                CONF_PLATFORM: "mqtt",
-                "devices": {dev_id: subscription},
-            }
-        },
+        DOMAIN,
+        {DOMAIN: {CONF_PLATFORM: "mqtt", "devices": {dev_id: subscription}}},
     )
     async_fire_mqtt_message(hass, topic, location)
     await hass.async_block_till_done()
@@ -166,7 +133,7 @@ async def test_matching_custom_payload_for_home_and_not_home(
 ):
     """Test custom payload_home sets state to home and custom payload_not_home sets state to not_home."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     topic = "/location/paulus"
     payload_home = "present"
     payload_not_home = "not present"
@@ -174,9 +141,9 @@ async def test_matching_custom_payload_for_home_and_not_home(
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
+        DOMAIN,
         {
-            device_tracker.DOMAIN: {
+            DOMAIN: {
                 CONF_PLATFORM: "mqtt",
                 "devices": {dev_id: topic},
                 "payload_home": payload_home,
@@ -198,7 +165,7 @@ async def test_not_matching_custom_payload_for_home_and_not_home(
 ):
     """Test not matching payload does not set state to home or not_home."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     topic = "/location/paulus"
     payload_home = "present"
     payload_not_home = "not present"
@@ -207,9 +174,9 @@ async def test_not_matching_custom_payload_for_home_and_not_home(
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
+        DOMAIN,
         {
-            device_tracker.DOMAIN: {
+            DOMAIN: {
                 CONF_PLATFORM: "mqtt",
                 "devices": {dev_id: topic},
                 "payload_home": payload_home,
@@ -226,7 +193,7 @@ async def test_not_matching_custom_payload_for_home_and_not_home(
 async def test_matching_source_type(hass, mock_device_tracker_conf):
     """Test setting source type."""
     dev_id = "paulus"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DOMAIN}.{dev_id}"
     topic = "/location/paulus"
     source_type = SOURCE_TYPE_BLUETOOTH
     location = "work"
@@ -234,9 +201,9 @@ async def test_matching_source_type(hass, mock_device_tracker_conf):
     hass.config.components = set(["mqtt", "zone"])
     assert await async_setup_component(
         hass,
-        device_tracker.DOMAIN,
+        DOMAIN,
         {
-            device_tracker.DOMAIN: {
+            DOMAIN: {
                 CONF_PLATFORM: "mqtt",
                 "devices": {dev_id: topic},
                 "source_type": source_type,
diff --git a/tests/components/mqtt_json/test_device_tracker.py b/tests/components/mqtt_json/test_device_tracker.py
index 5af196c5bf2..9efff135fe2 100644
--- a/tests/components/mqtt_json/test_device_tracker.py
+++ b/tests/components/mqtt_json/test_device_tracker.py
@@ -8,7 +8,6 @@ import pytest
 
 from homeassistant.components.device_tracker.legacy import (
     DOMAIN as DT_DOMAIN,
-    ENTITY_ID_FORMAT,
     YAML_DEVICES,
 )
 from homeassistant.const import CONF_PLATFORM
@@ -161,7 +160,7 @@ async def test_multi_level_wildcard_topic(hass):
 async def test_single_level_wildcard_topic_not_matching(hass):
     """Test not matching single level wildcard topic."""
     dev_id = "zanzito"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DT_DOMAIN}.{dev_id}"
     subscription = "location/+/zanzito"
     topic = "location/zanzito"
     location = json.dumps(LOCATION_MESSAGE)
@@ -179,7 +178,7 @@ async def test_single_level_wildcard_topic_not_matching(hass):
 async def test_multi_level_wildcard_topic_not_matching(hass):
     """Test not matching multi level wildcard topic."""
     dev_id = "zanzito"
-    entity_id = ENTITY_ID_FORMAT.format(dev_id)
+    entity_id = f"{DT_DOMAIN}.{dev_id}"
     subscription = "location/#"
     topic = "somewhere/zanzito"
     location = json.dumps(LOCATION_MESSAGE)