diff --git a/CODEOWNERS b/CODEOWNERS
index 1f3ce12e63a..26d1a8da2f8 100644
--- a/CODEOWNERS
+++ b/CODEOWNERS
@@ -587,6 +587,8 @@ build.json @home-assistant/supervisor
 /tests/components/lacrosse_view/ @IceBotYT
 /homeassistant/components/lametric/ @robbiet480 @frenck
 /tests/components/lametric/ @robbiet480 @frenck
+/homeassistant/components/landisgyr_heat_meter/ @vpathuis
+/tests/components/landisgyr_heat_meter/ @vpathuis
 /homeassistant/components/launch_library/ @ludeeus @DurgNomis-drol
 /tests/components/launch_library/ @ludeeus @DurgNomis-drol
 /homeassistant/components/laundrify/ @xLarry
diff --git a/homeassistant/components/landisgyr_heat_meter/__init__.py b/homeassistant/components/landisgyr_heat_meter/__init__.py
new file mode 100644
index 00000000000..b5a9a3fba79
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/__init__.py
@@ -0,0 +1,56 @@
+"""The Landis+Gyr Heat Meter integration."""
+from __future__ import annotations
+
+import logging
+
+from ultraheat_api import HeatMeterService, UltraheatReader
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import CONF_DEVICE, Platform
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.update_coordinator import DataUpdateCoordinator
+
+from .const import DOMAIN
+
+_LOGGER = logging.getLogger(__name__)
+
+PLATFORMS: list[Platform] = [Platform.SENSOR]
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Set up heat meter from a config entry."""
+
+    _LOGGER.debug("Initializing %s integration on %s", DOMAIN, entry.data[CONF_DEVICE])
+    reader = UltraheatReader(entry.data[CONF_DEVICE])
+
+    api = HeatMeterService(reader)
+
+    async def async_update_data():
+        """Fetch data from the API."""
+        _LOGGER.info("Polling on %s", entry.data[CONF_DEVICE])
+        return await hass.async_add_executor_job(api.read)
+
+    # No automatic polling and no initial refresh of data is being done at this point,
+    # to prevent battery drain. The user will have to do it manually.
+
+    coordinator = DataUpdateCoordinator(
+        hass,
+        _LOGGER,
+        name="ultraheat_gateway",
+        update_method=async_update_data,
+        update_interval=None,
+    )
+
+    hass.data.setdefault(DOMAIN, {})[entry.entry_id] = coordinator
+
+    hass.config_entries.async_setup_platforms(entry, PLATFORMS)
+
+    return True
+
+
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Unload a config entry."""
+    if unload_ok := await hass.config_entries.async_unload_platforms(entry, PLATFORMS):
+        hass.data[DOMAIN].pop(entry.entry_id)
+
+    return unload_ok
diff --git a/homeassistant/components/landisgyr_heat_meter/config_flow.py b/homeassistant/components/landisgyr_heat_meter/config_flow.py
new file mode 100644
index 00000000000..e3dbbb7433b
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/config_flow.py
@@ -0,0 +1,136 @@
+"""Config flow for Landis+Gyr Heat Meter integration."""
+from __future__ import annotations
+
+import logging
+import os
+
+import async_timeout
+import serial
+import serial.tools.list_ports
+from ultraheat_api import HeatMeterService, UltraheatReader
+import voluptuous as vol
+
+from homeassistant import config_entries
+from homeassistant.const import CONF_DEVICE
+from homeassistant.exceptions import HomeAssistantError
+
+from .const import DOMAIN
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_MANUAL_PATH = "Enter Manually"
+
+STEP_USER_DATA_SCHEMA = vol.Schema(
+    {
+        vol.Required(CONF_DEVICE): str,
+    }
+)
+
+
+class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for Ultraheat Heat Meter."""
+
+    VERSION = 1
+
+    async def async_step_user(self, user_input=None):
+        """Step when setting up serial configuration."""
+        errors = {}
+
+        if user_input is not None:
+            if user_input[CONF_DEVICE] == CONF_MANUAL_PATH:
+                return await self.async_step_setup_serial_manual_path()
+
+            dev_path = await self.hass.async_add_executor_job(
+                get_serial_by_id, user_input[CONF_DEVICE]
+            )
+
+            try:
+                return await self.validate_and_create_entry(dev_path)
+            except CannotConnect:
+                errors["base"] = "cannot_connect"
+
+        ports = await self.get_ports()
+
+        schema = vol.Schema({vol.Required(CONF_DEVICE): vol.In(ports)})
+        return self.async_show_form(step_id="user", data_schema=schema, errors=errors)
+
+    async def async_step_setup_serial_manual_path(self, user_input=None):
+        """Set path manually."""
+        errors = {}
+
+        if user_input is not None:
+            dev_path = user_input[CONF_DEVICE]
+            try:
+                return await self.validate_and_create_entry(dev_path)
+            except CannotConnect:
+                errors["base"] = "cannot_connect"
+
+        schema = vol.Schema({vol.Required(CONF_DEVICE): str})
+        return self.async_show_form(
+            step_id="setup_serial_manual_path",
+            data_schema=schema,
+            errors=errors,
+        )
+
+    async def validate_and_create_entry(self, dev_path):
+        """Try to connect to the device path and return an entry."""
+        model, device_number = await self.validate_ultraheat(dev_path)
+
+        await self.async_set_unique_id(device_number)
+        self._abort_if_unique_id_configured()
+        data = {
+            CONF_DEVICE: dev_path,
+            "model": model,
+            "device_number": device_number,
+        }
+        return self.async_create_entry(
+            title=model,
+            data=data,
+        )
+
+    async def validate_ultraheat(self, port: str):
+        """Validate the user input allows us to connect."""
+
+        reader = UltraheatReader(port)
+        heat_meter = HeatMeterService(reader)
+        try:
+            async with async_timeout.timeout(10):
+                # validate and retrieve the model and device number for a unique id
+                data = await self.hass.async_add_executor_job(heat_meter.read)
+                _LOGGER.debug("Got data from Ultraheat API: %s", data)
+
+        except Exception as err:
+            _LOGGER.warning("Failed read data from: %s. %s", port, err)
+            raise CannotConnect(f"Error communicating with device: {err}") from err
+
+        _LOGGER.debug("Successfully connected to %s", port)
+        return data.model, data.device_number
+
+    async def get_ports(self) -> dict:
+        """Get the available ports."""
+        ports = await self.hass.async_add_executor_job(serial.tools.list_ports.comports)
+        formatted_ports = {}
+        for port in ports:
+            formatted_ports[
+                port.device
+            ] = f"{port}, s/n: {port.serial_number or 'n/a'}" + (
+                f" - {port.manufacturer}" if port.manufacturer else ""
+            )
+        formatted_ports[CONF_MANUAL_PATH] = CONF_MANUAL_PATH
+        return formatted_ports
+
+
+def get_serial_by_id(dev_path: str) -> str:
+    """Return a /dev/serial/by-id match for given device if available."""
+    by_id = "/dev/serial/by-id"
+    if not os.path.isdir(by_id):
+        return dev_path
+
+    for path in (entry.path for entry in os.scandir(by_id) if entry.is_symlink()):
+        if os.path.realpath(path) == dev_path:
+            return path
+    return dev_path
+
+
+class CannotConnect(HomeAssistantError):
+    """Error to indicate we cannot connect."""
diff --git a/homeassistant/components/landisgyr_heat_meter/const.py b/homeassistant/components/landisgyr_heat_meter/const.py
new file mode 100644
index 00000000000..70008890d1f
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/const.py
@@ -0,0 +1,192 @@
+"""Constants for the Landis+Gyr Heat Meter integration."""
+
+from homeassistant.components.sensor import (
+    SensorDeviceClass,
+    SensorEntityDescription,
+    SensorStateClass,
+)
+from homeassistant.const import ENERGY_MEGA_WATT_HOUR, TEMP_CELSIUS, VOLUME_CUBIC_METERS
+from homeassistant.helpers.entity import EntityCategory
+
+DOMAIN = "landisgyr_heat_meter"
+
+GJ_TO_MWH = 0.277778  # conversion factor
+
+HEAT_METER_SENSOR_TYPES = (
+    SensorEntityDescription(
+        key="heat_usage",
+        icon="mdi:fire",
+        name="Heat usage",
+        native_unit_of_measurement=ENERGY_MEGA_WATT_HOUR,
+        device_class=SensorDeviceClass.ENERGY,
+        state_class=SensorStateClass.TOTAL,
+    ),
+    SensorEntityDescription(
+        key="volume_usage_m3",
+        icon="mdi:fire",
+        name="Volume usage",
+        native_unit_of_measurement=VOLUME_CUBIC_METERS,
+        state_class=SensorStateClass.TOTAL,
+    ),
+    # Diagnostic entity for debugging, this will match the value in GJ indicated on the meter's display
+    SensorEntityDescription(
+        key="heat_usage_gj",
+        icon="mdi:fire",
+        name="Heat usage GJ",
+        native_unit_of_measurement="GJ",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="heat_previous_year",
+        icon="mdi:fire",
+        name="Heat usage previous year",
+        native_unit_of_measurement=ENERGY_MEGA_WATT_HOUR,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="volume_previous_year_m3",
+        icon="mdi:fire",
+        name="Volume usage previous year",
+        native_unit_of_measurement=VOLUME_CUBIC_METERS,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="ownership_number",
+        name="Ownership number",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="error_number",
+        name="Error number",
+        icon="mdi:home-alert",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="device_number",
+        name="Device number",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="measurement_period_minutes",
+        name="Measurement period minutes",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="power_max_kw",
+        name="Power max",
+        native_unit_of_measurement="kW",
+        icon="mdi:power-plug-outline",
+        device_class=SensorDeviceClass.POWER,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="power_max_previous_year_kw",
+        name="Power max previous year",
+        native_unit_of_measurement="kW",
+        icon="mdi:power-plug-outline",
+        device_class=SensorDeviceClass.POWER,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="flowrate_max_m3ph",
+        name="Flowrate max",
+        native_unit_of_measurement="m3ph",
+        icon="mdi:water-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="flowrate_max_previous_year_m3ph",
+        name="Flowrate max previous year",
+        native_unit_of_measurement="m3ph",
+        icon="mdi:water-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="return_temperature_max_c",
+        name="Return temperature max",
+        native_unit_of_measurement=TEMP_CELSIUS,
+        icon="mdi:thermometer",
+        device_class=SensorDeviceClass.TEMPERATURE,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="return_temperature_max_previous_year_c",
+        name="Return temperature max previous year",
+        native_unit_of_measurement=TEMP_CELSIUS,
+        icon="mdi:thermometer",
+        device_class=SensorDeviceClass.TEMPERATURE,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="flow_temperature_max_c",
+        name="Flow temperature max",
+        native_unit_of_measurement=TEMP_CELSIUS,
+        icon="mdi:thermometer",
+        device_class=SensorDeviceClass.TEMPERATURE,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="flow_temperature_max_previous_year_c",
+        name="Flow temperature max previous year",
+        native_unit_of_measurement=TEMP_CELSIUS,
+        icon="mdi:thermometer",
+        device_class=SensorDeviceClass.TEMPERATURE,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="operating_hours",
+        name="Operating hours",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="flow_hours",
+        name="Flow hours",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="fault_hours",
+        name="Fault hours",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="fault_hours_previous_year",
+        name="Fault hours previous year",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="yearly_set_day",
+        name="Yearly set day",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="monthly_set_day",
+        name="Monthly set day",
+        icon="mdi:clock-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="meter_date_time",
+        name="Meter date time",
+        icon="mdi:clock-outline",
+        device_class=SensorDeviceClass.TIMESTAMP,
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="measuring_range_m3ph",
+        name="Measuring range",
+        native_unit_of_measurement="m3ph",
+        icon="mdi:water-outline",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    SensorEntityDescription(
+        key="settings_and_firmware",
+        name="Settings and firmware",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+)
diff --git a/homeassistant/components/landisgyr_heat_meter/manifest.json b/homeassistant/components/landisgyr_heat_meter/manifest.json
new file mode 100644
index 00000000000..359ca1acea6
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/manifest.json
@@ -0,0 +1,13 @@
+{
+  "domain": "landisgyr_heat_meter",
+  "name": "Landis+Gyr Heat Meter",
+  "config_flow": true,
+  "documentation": "https://www.home-assistant.io/integrations/landisgyr_heat_meter",
+  "requirements": ["ultraheat-api==0.4.1"],
+  "ssdp": [],
+  "zeroconf": [],
+  "homekit": {},
+  "dependencies": [],
+  "codeowners": ["@vpathuis"],
+  "iot_class": "local_polling"
+}
diff --git a/homeassistant/components/landisgyr_heat_meter/sensor.py b/homeassistant/components/landisgyr_heat_meter/sensor.py
new file mode 100644
index 00000000000..1d38b1f5816
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/sensor.py
@@ -0,0 +1,108 @@
+"""Platform for sensor integration."""
+from __future__ import annotations
+
+from dataclasses import asdict
+import logging
+
+from homeassistant.components.sensor import (
+    ATTR_STATE_CLASS,
+    RestoreSensor,
+    SensorDeviceClass,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import ATTR_DEVICE_CLASS, ATTR_UNIT_OF_MEASUREMENT
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.update_coordinator import CoordinatorEntity
+from homeassistant.util import dt as dt_util
+
+from . import DOMAIN
+from .const import GJ_TO_MWH, HEAT_METER_SENSOR_TYPES
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_setup_entry(
+    hass: HomeAssistant, entry: ConfigEntry, async_add_entities: AddEntitiesCallback
+) -> None:
+    """Set up the sensor platform."""
+    _LOGGER.info("The Landis+Gyr Heat Meter sensor platform is being set up!")
+
+    unique_id = entry.entry_id
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    model = entry.data["model"]
+
+    device = DeviceInfo(
+        identifiers={(DOMAIN, unique_id)},
+        manufacturer="Landis & Gyr",
+        model=model,
+        name="Landis+Gyr Heat Meter",
+    )
+
+    sensors = []
+
+    for description in HEAT_METER_SENSOR_TYPES:
+        sensors.append(HeatMeterSensor(coordinator, unique_id, description, device))
+
+    async_add_entities(sensors)
+
+
+class HeatMeterSensor(CoordinatorEntity, RestoreSensor):
+    """Representation of a Sensor."""
+
+    def __init__(self, coordinator, unique_id, description, device):
+        """Set up the sensor with the initial values."""
+        super().__init__(coordinator)
+        self.key = description.key
+        self._attr_unique_id = f"{DOMAIN}_{unique_id}_{description.key}"
+        self._attr_name = "Heat Meter " + description.name
+        if hasattr(description, "icon"):
+            self._attr_icon = description.icon
+        if hasattr(description, "entity_category"):
+            self._attr_entity_category = description.entity_category
+        if hasattr(description, ATTR_STATE_CLASS):
+            self._attr_state_class = description.state_class
+        if hasattr(description, ATTR_DEVICE_CLASS):
+            self._attr_device_class = description.device_class
+        if hasattr(description, ATTR_UNIT_OF_MEASUREMENT):
+            self._attr_native_unit_of_measurement = (
+                description.native_unit_of_measurement
+            )
+        self._attr_device_info = device
+        self._attr_should_poll = bool(self.key in ("heat_usage", "heat_previous_year"))
+
+    async def async_added_to_hass(self):
+        """Call when entity about to be added to hass."""
+        await super().async_added_to_hass()
+        state = await self.async_get_last_sensor_data()
+        if state:
+            self._attr_native_value = state.native_value
+
+    def _handle_coordinator_update(self) -> None:
+        """Handle updated data from the coordinator."""
+        if self.key in asdict(self.coordinator.data):
+            if self.device_class == SensorDeviceClass.TIMESTAMP:
+                self._attr_native_value = dt_util.as_utc(
+                    asdict(self.coordinator.data)[self.key]
+                )
+            else:
+                self._attr_native_value = asdict(self.coordinator.data)[self.key]
+
+        if self.key == "heat_usage":
+            self._attr_native_value = convert_gj_to_mwh(
+                self.coordinator.data.heat_usage_gj
+            )
+
+        if self.key == "heat_previous_year":
+            self._attr_native_value = convert_gj_to_mwh(
+                self.coordinator.data.heat_previous_year_gj
+            )
+
+        self.async_write_ha_state()
+
+
+def convert_gj_to_mwh(gigajoule) -> float:
+    """Convert GJ to MWh using the conversion value."""
+    return round(gigajoule * GJ_TO_MWH, 5)
diff --git a/homeassistant/components/landisgyr_heat_meter/strings.json b/homeassistant/components/landisgyr_heat_meter/strings.json
new file mode 100644
index 00000000000..61e170af2b3
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/strings.json
@@ -0,0 +1,23 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "data": {
+          "device": "Select device"
+        }
+      },
+      "setup_serial_manual_path": {
+        "data": {
+          "device": "[%key:common::config_flow::data::usb_path%]"
+        }
+      }
+    },
+    "error": {
+      "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
+      "unknown": "[%key:common::config_flow::error::unknown%]"
+    },
+    "abort": {
+      "already_configured": "[%key:common::config_flow::abort::already_configured_device%]"
+    }
+  }
+}
diff --git a/homeassistant/components/landisgyr_heat_meter/translations/en.json b/homeassistant/components/landisgyr_heat_meter/translations/en.json
new file mode 100644
index 00000000000..6915e8cb36a
--- /dev/null
+++ b/homeassistant/components/landisgyr_heat_meter/translations/en.json
@@ -0,0 +1,24 @@
+{
+    "config": {
+        "abort": {
+            "already_configured": "Device is already configured"
+        },
+        "error": {
+            "cannot_connect": "Failed to connect",
+            "invalid_auth": "Invalid authentication",
+            "unknown": "Unexpected error"
+        },
+        "step": {
+            "user": {
+                "data": {
+                    "device": "Select device"
+                }
+            },
+            "setup_serial_manual_path": {
+                "data": {
+                    "device": "USB-device path"
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/homeassistant/generated/config_flows.py b/homeassistant/generated/config_flows.py
index 42b426b8864..2ce09bfcafa 100644
--- a/homeassistant/generated/config_flows.py
+++ b/homeassistant/generated/config_flows.py
@@ -197,6 +197,7 @@ FLOWS = {
         "kulersky",
         "lacrosse_view",
         "lametric",
+        "landisgyr_heat_meter",
         "launch_library",
         "laundrify",
         "lg_soundbar",
diff --git a/requirements_all.txt b/requirements_all.txt
index 96dfac44800..ecaaf30280c 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -2383,6 +2383,9 @@ twitchAPI==2.5.2
 # homeassistant.components.ukraine_alarm
 uasiren==0.0.1
 
+# homeassistant.components.landisgyr_heat_meter
+ultraheat-api==0.4.1
+
 # homeassistant.components.unifiprotect
 unifi-discovery==1.1.5
 
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 2db72263205..2b72beee027 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -1614,6 +1614,9 @@ twitchAPI==2.5.2
 # homeassistant.components.ukraine_alarm
 uasiren==0.0.1
 
+# homeassistant.components.landisgyr_heat_meter
+ultraheat-api==0.4.1
+
 # homeassistant.components.unifiprotect
 unifi-discovery==1.1.5
 
diff --git a/tests/components/landisgyr_heat_meter/__init__.py b/tests/components/landisgyr_heat_meter/__init__.py
new file mode 100644
index 00000000000..0ee6eb22510
--- /dev/null
+++ b/tests/components/landisgyr_heat_meter/__init__.py
@@ -0,0 +1 @@
+"""Tests for the Landis+Gyr Heat Meter component."""
diff --git a/tests/components/landisgyr_heat_meter/test_config_flow.py b/tests/components/landisgyr_heat_meter/test_config_flow.py
new file mode 100644
index 00000000000..b51d4493879
--- /dev/null
+++ b/tests/components/landisgyr_heat_meter/test_config_flow.py
@@ -0,0 +1,227 @@
+"""Test the Landis + Gyr Heat Meter config flow."""
+from dataclasses import dataclass
+from unittest.mock import MagicMock, patch
+
+import serial.tools.list_ports
+
+from homeassistant import config_entries
+from homeassistant.components.landisgyr_heat_meter import DOMAIN
+from homeassistant.core import HomeAssistant
+from homeassistant.data_entry_flow import RESULT_TYPE_CREATE_ENTRY, RESULT_TYPE_FORM
+
+
+def mock_serial_port():
+    """Mock of a serial port."""
+    port = serial.tools.list_ports_common.ListPortInfo("/dev/ttyUSB1234")
+    port.serial_number = "1234"
+    port.manufacturer = "Virtual serial port"
+    port.device = "/dev/ttyUSB1234"
+    port.description = "Some serial port"
+
+    return port
+
+
+@dataclass
+class MockUltraheatRead:
+    """Mock of the response from the read method of the Ultraheat API."""
+
+    model: str
+    device_number: str
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+async def test_manual_entry(mock_heat_meter, hass: HomeAssistant) -> None:
+    """Test manual entry."""
+
+    mock_heat_meter().read.return_value = MockUltraheatRead("LUGCUH50", "123456789")
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"device": "Enter Manually"}
+    )
+
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "setup_serial_manual_path"
+    assert result["errors"] == {}
+
+    with patch(
+        "homeassistant.components.landisgyr_heat_meter.async_setup_entry",
+        return_value=True,
+    ):
+        result = await hass.config_entries.flow.async_configure(
+            result["flow_id"], {"device": "/dev/ttyUSB0"}
+        )
+
+    assert result["type"] == RESULT_TYPE_CREATE_ENTRY
+    assert result["title"] == "LUGCUH50"
+    assert result["data"] == {
+        "device": "/dev/ttyUSB0",
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+@patch("serial.tools.list_ports.comports", return_value=[mock_serial_port()])
+async def test_list_entry(mock_port, mock_heat_meter, hass: HomeAssistant) -> None:
+    """Test select from list entry."""
+
+    mock_heat_meter().read.return_value = MockUltraheatRead("LUGCUH50", "123456789")
+    port = mock_serial_port()
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"device": port.device}
+    )
+    assert result["type"] == RESULT_TYPE_CREATE_ENTRY
+    assert result["title"] == "LUGCUH50"
+    assert result["data"] == {
+        "device": port.device,
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+async def test_manual_entry_fail(mock_heat_meter, hass: HomeAssistant) -> None:
+    """Test manual entry fails."""
+
+    mock_heat_meter().read.side_effect = Exception
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"device": "Enter Manually"}
+    )
+
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "setup_serial_manual_path"
+    assert result["errors"] == {}
+
+    with patch(
+        "homeassistant.components.landisgyr_heat_meter.async_setup_entry",
+        return_value=True,
+    ):
+        result = await hass.config_entries.flow.async_configure(
+            result["flow_id"], {"device": "/dev/ttyUSB0"}
+        )
+
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "setup_serial_manual_path"
+    assert result["errors"] == {"base": "cannot_connect"}
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+@patch("serial.tools.list_ports.comports", return_value=[mock_serial_port()])
+async def test_list_entry_fail(mock_port, mock_heat_meter, hass: HomeAssistant) -> None:
+    """Test select from list entry fails."""
+
+    mock_heat_meter().read.side_effect = Exception
+    port = mock_serial_port()
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], {"device": port.device}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {"base": "cannot_connect"}
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+@patch("serial.tools.list_ports.comports", return_value=[mock_serial_port()])
+async def test_get_serial_by_id_realpath(
+    mock_port, mock_heat_meter, hass: HomeAssistant
+) -> None:
+    """Test getting the serial path name."""
+
+    mock_heat_meter().read.return_value = MockUltraheatRead("LUGCUH50", "123456789")
+    port = mock_serial_port()
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    scandir = [MagicMock(), MagicMock()]
+    scandir[0].path = "/dev/ttyUSB1234"
+    scandir[0].is_symlink.return_value = True
+    scandir[1].path = "/dev/ttyUSB5678"
+    scandir[1].is_symlink.return_value = True
+
+    with patch("os.path") as path:
+        with patch("os.scandir", return_value=scandir):
+            path.isdir.return_value = True
+            path.realpath.side_effect = ["/dev/ttyUSB1234", "/dev/ttyUSB5678"]
+            result = await hass.config_entries.flow.async_configure(
+                result["flow_id"], {"device": port.device}
+            )
+    assert result["type"] == RESULT_TYPE_CREATE_ENTRY
+    assert result["title"] == "LUGCUH50"
+    assert result["data"] == {
+        "device": port.device,
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.config_flow.HeatMeterService")
+@patch("serial.tools.list_ports.comports", return_value=[mock_serial_port()])
+async def test_get_serial_by_id_dev_path(
+    mock_port, mock_heat_meter, hass: HomeAssistant
+) -> None:
+    """Test getting the serial path name with no realpath result."""
+
+    mock_heat_meter().read.return_value = MockUltraheatRead("LUGCUH50", "123456789")
+    port = mock_serial_port()
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] == RESULT_TYPE_FORM
+    assert result["step_id"] == "user"
+    assert result["errors"] == {}
+
+    scandir = [MagicMock()]
+    scandir[0].path.return_value = "/dev/serial/by-id/USB5678"
+    scandir[0].is_symlink.return_value = True
+
+    with patch("os.path") as path:
+        with patch("os.scandir", return_value=scandir):
+            path.isdir.return_value = True
+            path.realpath.side_effect = ["/dev/ttyUSB5678"]
+            result = await hass.config_entries.flow.async_configure(
+                result["flow_id"], {"device": port.device}
+            )
+    assert result["type"] == RESULT_TYPE_CREATE_ENTRY
+    assert result["title"] == "LUGCUH50"
+    assert result["data"] == {
+        "device": port.device,
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
diff --git a/tests/components/landisgyr_heat_meter/test_init.py b/tests/components/landisgyr_heat_meter/test_init.py
new file mode 100644
index 00000000000..b3630fc4872
--- /dev/null
+++ b/tests/components/landisgyr_heat_meter/test_init.py
@@ -0,0 +1,22 @@
+"""Test the Landis + Gyr Heat Meter init."""
+
+from homeassistant.const import CONF_DEVICE
+
+from tests.common import MockConfigEntry
+
+
+async def test_unload_entry(hass):
+    """Test removing config entry."""
+    entry = MockConfigEntry(
+        domain="landisgyr_heat_meter",
+        title="LUGCUH50",
+        data={CONF_DEVICE: "/dev/1234"},
+    )
+
+    entry.add_to_hass(hass)
+
+    assert await hass.config_entries.async_setup(entry.entry_id)
+    await hass.async_block_till_done()
+    assert "landisgyr_heat_meter" in hass.config.components
+
+    assert await hass.config_entries.async_remove(entry.entry_id)
diff --git a/tests/components/landisgyr_heat_meter/test_sensor.py b/tests/components/landisgyr_heat_meter/test_sensor.py
new file mode 100644
index 00000000000..505efb446b8
--- /dev/null
+++ b/tests/components/landisgyr_heat_meter/test_sensor.py
@@ -0,0 +1,200 @@
+"""The tests for the Landis+Gyr Heat Meter sensor platform."""
+from dataclasses import dataclass
+import datetime
+from unittest.mock import patch
+
+from homeassistant.components.homeassistant import (
+    DOMAIN as HA_DOMAIN,
+    SERVICE_UPDATE_ENTITY,
+)
+from homeassistant.components.landisgyr_heat_meter.const import DOMAIN
+from homeassistant.components.sensor import (
+    ATTR_LAST_RESET,
+    ATTR_STATE_CLASS,
+    SensorDeviceClass,
+    SensorStateClass,
+)
+from homeassistant.const import (
+    ATTR_DEVICE_CLASS,
+    ATTR_ENTITY_ID,
+    ATTR_ICON,
+    ATTR_UNIT_OF_MEASUREMENT,
+    ENERGY_MEGA_WATT_HOUR,
+    VOLUME_CUBIC_METERS,
+)
+from homeassistant.core import CoreState, State
+from homeassistant.helpers import entity_registry
+from homeassistant.helpers.entity import EntityCategory
+from homeassistant.setup import async_setup_component
+from homeassistant.util import dt as dt_util
+
+from tests.common import MockConfigEntry, mock_restore_cache_with_extra_data
+
+
+@dataclass
+class MockHeatMeterResponse:
+    """Mock for HeatMeterResponse."""
+
+    heat_usage_gj: int
+    volume_usage_m3: int
+    heat_previous_year_gj: int
+    device_number: str
+    meter_date_time: datetime.datetime
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.HeatMeterService")
+async def test_create_sensors(mock_heat_meter, hass):
+    """Test sensor."""
+    entry_data = {
+        "device": "/dev/USB0",
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
+    mock_entry = MockConfigEntry(domain=DOMAIN, unique_id=DOMAIN, data=entry_data)
+
+    mock_entry.add_to_hass(hass)
+
+    mock_heat_meter_response = MockHeatMeterResponse(
+        heat_usage_gj=123,
+        volume_usage_m3=456,
+        heat_previous_year_gj=111,
+        device_number="devicenr_789",
+        meter_date_time=dt_util.as_utc(datetime.datetime(2022, 5, 19, 19, 41, 17)),
+    )
+
+    mock_heat_meter().read.return_value = mock_heat_meter_response
+
+    await hass.config_entries.async_setup(mock_entry.entry_id)
+    await async_setup_component(hass, HA_DOMAIN, {})
+    await hass.async_block_till_done()
+    await hass.services.async_call(
+        HA_DOMAIN,
+        SERVICE_UPDATE_ENTITY,
+        {ATTR_ENTITY_ID: "sensor.heat_meter_heat_usage"},
+        blocking=True,
+    )
+    await hass.async_block_till_done()
+
+    # check if 26 attributes have been created
+    assert len(hass.states.async_all()) == 26
+    entity_reg = entity_registry.async_get(hass)
+
+    state = hass.states.get("sensor.heat_meter_heat_usage")
+    assert state
+    assert state.state == "34.16669"
+    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == ENERGY_MEGA_WATT_HOUR
+    assert state.attributes.get(ATTR_STATE_CLASS) == SensorStateClass.TOTAL
+    assert state.attributes.get(ATTR_DEVICE_CLASS) == SensorDeviceClass.ENERGY
+
+    state = hass.states.get("sensor.heat_meter_volume_usage")
+    assert state
+    assert state.state == "456"
+    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == VOLUME_CUBIC_METERS
+    assert state.attributes.get(ATTR_STATE_CLASS) == SensorStateClass.TOTAL
+
+    state = hass.states.get("sensor.heat_meter_device_number")
+    assert state
+    assert state.state == "devicenr_789"
+    assert state.attributes.get(ATTR_STATE_CLASS) is None
+    entity_registry_entry = entity_reg.async_get("sensor.heat_meter_device_number")
+    assert entity_registry_entry.entity_category == EntityCategory.DIAGNOSTIC
+
+    state = hass.states.get("sensor.heat_meter_meter_date_time")
+    assert state
+    assert state.attributes.get(ATTR_ICON) == "mdi:clock-outline"
+    assert state.attributes.get(ATTR_STATE_CLASS) is None
+    entity_registry_entry = entity_reg.async_get("sensor.heat_meter_meter_date_time")
+    assert entity_registry_entry.entity_category == EntityCategory.DIAGNOSTIC
+
+
+@patch("homeassistant.components.landisgyr_heat_meter.HeatMeterService")
+async def test_restore_state(mock_heat_meter, hass):
+    """Test sensor restore state."""
+    # Home assistant is not running yet
+    hass.state = CoreState.not_running
+    last_reset = "2022-07-01T00:00:00.000000+00:00"
+    mock_restore_cache_with_extra_data(
+        hass,
+        [
+            (
+                State(
+                    "sensor.heat_meter_heat_usage",
+                    "34167",
+                    attributes={
+                        ATTR_LAST_RESET: last_reset,
+                        ATTR_UNIT_OF_MEASUREMENT: ENERGY_MEGA_WATT_HOUR,
+                        ATTR_STATE_CLASS: SensorStateClass.TOTAL,
+                    },
+                ),
+                {
+                    "native_value": 34167,
+                    "native_unit_of_measurement": ENERGY_MEGA_WATT_HOUR,
+                    "icon": "mdi:fire",
+                    "last_reset": last_reset,
+                },
+            ),
+            (
+                State(
+                    "sensor.heat_meter_volume_usage",
+                    "456",
+                    attributes={
+                        ATTR_LAST_RESET: last_reset,
+                        ATTR_UNIT_OF_MEASUREMENT: VOLUME_CUBIC_METERS,
+                        ATTR_STATE_CLASS: SensorStateClass.TOTAL,
+                    },
+                ),
+                {
+                    "native_value": 456,
+                    "native_unit_of_measurement": VOLUME_CUBIC_METERS,
+                    "icon": "mdi:fire",
+                    "last_reset": last_reset,
+                },
+            ),
+            (
+                State(
+                    "sensor.heat_meter_device_number",
+                    "devicenr_789",
+                    attributes={
+                        ATTR_LAST_RESET: last_reset,
+                    },
+                ),
+                {
+                    "native_value": "devicenr_789",
+                    "native_unit_of_measurement": None,
+                    "last_reset": last_reset,
+                },
+            ),
+        ],
+    )
+    entry_data = {
+        "device": "/dev/USB0",
+        "model": "LUGCUH50",
+        "device_number": "123456789",
+    }
+
+    # create and add entry
+    mock_entry = MockConfigEntry(domain=DOMAIN, unique_id=DOMAIN, data=entry_data)
+    mock_entry.add_to_hass(hass)
+
+    await hass.config_entries.async_setup(mock_entry.entry_id)
+    await async_setup_component(hass, HA_DOMAIN, {})
+    await hass.async_block_till_done()
+
+    # restore from cache
+    state = hass.states.get("sensor.heat_meter_heat_usage")
+    assert state
+    assert state.state == "34167"
+    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == ENERGY_MEGA_WATT_HOUR
+    assert state.attributes.get(ATTR_STATE_CLASS) == SensorStateClass.TOTAL
+
+    state = hass.states.get("sensor.heat_meter_volume_usage")
+    assert state
+    assert state.state == "456"
+    assert state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) == VOLUME_CUBIC_METERS
+    assert state.attributes.get(ATTR_STATE_CLASS) == SensorStateClass.TOTAL
+
+    state = hass.states.get("sensor.heat_meter_device_number")
+    assert state
+    print("STATE IS: ", state)
+    assert state.state == "devicenr_789"
+    assert state.attributes.get(ATTR_STATE_CLASS) is None