diff --git a/.strict-typing b/.strict-typing
index 4c9e626afa6..66a965b3221 100644
--- a/.strict-typing
+++ b/.strict-typing
@@ -137,6 +137,7 @@ homeassistant.components.uptime.*
 homeassistant.components.uptimerobot.*
 homeassistant.components.vacuum.*
 homeassistant.components.vallox.*
+homeassistant.components.velbus.*
 homeassistant.components.vlc_telnet.*
 homeassistant.components.water_heater.*
 homeassistant.components.watttime.*
diff --git a/homeassistant/components/velbus/__init__.py b/homeassistant/components/velbus/__init__.py
index d907557bb01..be5ce04051c 100644
--- a/homeassistant/components/velbus/__init__.py
+++ b/homeassistant/components/velbus/__init__.py
@@ -3,16 +3,18 @@ from __future__ import annotations
 
 import logging
 
+from velbusaio.channels import Channel as VelbusChannel
 from velbusaio.controller import Velbus
 import voluptuous as vol
 
 from homeassistant.config_entries import SOURCE_IMPORT, ConfigEntry
 from homeassistant.const import CONF_ADDRESS, CONF_NAME, CONF_PORT
-from homeassistant.core import HomeAssistant
+from homeassistant.core import HomeAssistant, ServiceCall
 from homeassistant.helpers import device_registry
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.device_registry import DeviceEntry
 from homeassistant.helpers.entity import DeviceInfo, Entity
+from homeassistant.helpers.typing import ConfigType
 
 from .const import (
     CONF_INTERFACE,
@@ -32,7 +34,7 @@ CONFIG_SCHEMA = vol.Schema(
 PLATFORMS = ["switch", "sensor", "binary_sensor", "cover", "climate", "light"]
 
 
-async def async_setup(hass, config):
+async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Set up the Velbus platform."""
     # Import from the configuration file if needed
     if DOMAIN not in config:
@@ -97,7 +99,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     if hass.services.has_service(DOMAIN, SERVICE_SCAN):
         return True
 
-    def check_entry_id(interface: str):
+    def check_entry_id(interface: str) -> str:
         for entry in hass.config_entries.async_entries(DOMAIN):
             if "port" in entry.data and entry.data["port"] == interface:
                 return entry.entry_id
@@ -105,7 +107,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             "The interface provided is not defined as a port in a Velbus integration"
         )
 
-    async def scan(call):
+    async def scan(call: ServiceCall) -> None:
         await hass.data[DOMAIN][call.data[CONF_INTERFACE]]["cntrl"].scan()
 
     hass.services.async_register(
@@ -115,7 +117,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         vol.Schema({vol.Required(CONF_INTERFACE): vol.All(cv.string, check_entry_id)}),
     )
 
-    async def syn_clock(call):
+    async def syn_clock(call: ServiceCall) -> None:
         await hass.data[DOMAIN][call.data[CONF_INTERFACE]]["cntrl"].sync_clock()
 
     hass.services.async_register(
@@ -125,7 +127,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         vol.Schema({vol.Required(CONF_INTERFACE): vol.All(cv.string, check_entry_id)}),
     )
 
-    async def set_memo_text(call):
+    async def set_memo_text(call: ServiceCall) -> None:
         """Handle Memo Text service call."""
         memo_text = call.data[CONF_MEMO_TEXT]
         memo_text.hass = hass
@@ -167,32 +169,32 @@ async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 class VelbusEntity(Entity):
     """Representation of a Velbus entity."""
 
-    def __init__(self, channel):
+    def __init__(self, channel: VelbusChannel) -> None:
         """Initialize a Velbus entity."""
         self._channel = channel
 
     @property
-    def unique_id(self):
+    def unique_id(self) -> str:
         """Get unique ID."""
-        if (serial := self._channel.get_module_serial()) == 0:
-            serial = self._channel.get_module_address()
+        if (serial := self._channel.get_module_serial()) == "":
+            serial = str(self._channel.get_module_address())
         return f"{serial}-{self._channel.get_channel_number()}"
 
     @property
-    def name(self):
+    def name(self) -> str:
         """Return the display name of this entity."""
         return self._channel.get_name()
 
     @property
-    def should_poll(self):
+    def should_poll(self) -> bool:
         """Disable polling."""
         return False
 
-    async def async_added_to_hass(self):
+    async def async_added_to_hass(self) -> None:
         """Add listener for state changes."""
         self._channel.on_status_update(self._on_update)
 
-    async def _on_update(self):
+    async def _on_update(self) -> None:
         self.async_write_ha_state()
 
     @property
@@ -200,7 +202,7 @@ class VelbusEntity(Entity):
         """Return the device info."""
         return DeviceInfo(
             identifiers={
-                (DOMAIN, self._channel.get_module_address()),
+                (DOMAIN, str(self._channel.get_module_address())),
             },
             manufacturer="Velleman",
             model=self._channel.get_module_type_name(),
diff --git a/homeassistant/components/velbus/binary_sensor.py b/homeassistant/components/velbus/binary_sensor.py
index 014b1410fdc..8c67520dd9a 100644
--- a/homeassistant/components/velbus/binary_sensor.py
+++ b/homeassistant/components/velbus/binary_sensor.py
@@ -1,4 +1,6 @@
 """Support for Velbus Binary Sensors."""
+from velbusaio.channels import Button as VelbusButton
+
 from homeassistant.components.binary_sensor import BinarySensorEntity
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
@@ -25,6 +27,8 @@ async def async_setup_entry(
 class VelbusBinarySensor(VelbusEntity, BinarySensorEntity):
     """Representation of a Velbus Binary Sensor."""
 
+    _channel: VelbusButton
+
     @property
     def is_on(self) -> bool:
         """Return true if the sensor is on."""
diff --git a/homeassistant/components/velbus/climate.py b/homeassistant/components/velbus/climate.py
index a065679c4e5..c11698b1358 100644
--- a/homeassistant/components/velbus/climate.py
+++ b/homeassistant/components/velbus/climate.py
@@ -1,6 +1,10 @@
 """Support for Velbus thermostat."""
 from __future__ import annotations
 
+from typing import Any
+
+from velbusaio.channels import Temperature as VelbusTemp
+
 from homeassistant.components.climate import ClimateEntity
 from homeassistant.components.climate.const import (
     HVAC_MODE_HEAT,
@@ -33,6 +37,7 @@ async def async_setup_entry(
 class VelbusClimate(VelbusEntity, ClimateEntity):
     """Representation of a Velbus thermostat."""
 
+    _channel: VelbusTemp
     _attr_supported_features = SUPPORT_TARGET_TEMPERATURE | SUPPORT_PRESET_MODE
     _attr_temperature_unit = TEMP_CELSIUS
     _attr_hvac_mode = HVAC_MODE_HEAT
@@ -40,7 +45,7 @@ class VelbusClimate(VelbusEntity, ClimateEntity):
     _attr_preset_modes = list(PRESET_MODES)
 
     @property
-    def target_temperature(self) -> int | None:
+    def target_temperature(self) -> float | None:
         """Return the temperature we try to reach."""
         return self._channel.get_climate_target()
 
@@ -56,7 +61,7 @@ class VelbusClimate(VelbusEntity, ClimateEntity):
             None,
         )
 
-    async def async_set_temperature(self, **kwargs) -> None:
+    async def async_set_temperature(self, **kwargs: Any) -> None:
         """Set new target temperatures."""
         if (temp := kwargs.get(ATTR_TEMPERATURE)) is None:
             return
diff --git a/homeassistant/components/velbus/config_flow.py b/homeassistant/components/velbus/config_flow.py
index 3ec5af14397..3facd8c6a33 100644
--- a/homeassistant/components/velbus/config_flow.py
+++ b/homeassistant/components/velbus/config_flow.py
@@ -1,6 +1,8 @@
 """Config flow for the Velbus platform."""
 from __future__ import annotations
 
+from typing import Any
+
 import velbusaio
 from velbusaio.exceptions import VelbusConnectionFailed
 import voluptuous as vol
@@ -8,16 +10,17 @@ import voluptuous as vol
 from homeassistant import config_entries
 from homeassistant.const import CONF_NAME, CONF_PORT
 from homeassistant.core import HomeAssistant, callback
+from homeassistant.data_entry_flow import FlowResult
 from homeassistant.util import slugify
 
 from .const import DOMAIN
 
 
 @callback
-def velbus_entries(hass: HomeAssistant):
+def velbus_entries(hass: HomeAssistant) -> set[str]:
     """Return connections for Velbus domain."""
     return {
-        (entry.data[CONF_PORT]) for entry in hass.config_entries.async_entries(DOMAIN)
+        entry.data[CONF_PORT] for entry in hass.config_entries.async_entries(DOMAIN)
     }
 
 
@@ -30,11 +33,11 @@ class VelbusConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
         """Initialize the velbus config flow."""
         self._errors: dict[str, str] = {}
 
-    def _create_device(self, name: str, prt: str):
+    def _create_device(self, name: str, prt: str) -> FlowResult:
         """Create an entry async."""
         return self.async_create_entry(title=name, data={CONF_PORT: prt})
 
-    async def _test_connection(self, prt):
+    async def _test_connection(self, prt: str) -> bool:
         """Try to connect to the velbus with the port specified."""
         try:
             controller = velbusaio.controller.Velbus(prt)
@@ -51,7 +54,9 @@ class VelbusConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             return True
         return False
 
-    async def async_step_user(self, user_input=None):
+    async def async_step_user(
+        self, user_input: dict[str, Any] | None = None
+    ) -> FlowResult:
         """Step when user initializes a integration."""
         self._errors = {}
         if user_input is not None:
@@ -78,7 +83,7 @@ class VelbusConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             errors=self._errors,
         )
 
-    async def async_step_import(self, user_input=None):
+    async def async_step_import(self, user_input: dict[str, Any]) -> FlowResult:
         """Import a config entry."""
         user_input[CONF_NAME] = "Velbus Import"
         prt = user_input[CONF_PORT]
diff --git a/homeassistant/components/velbus/cover.py b/homeassistant/components/velbus/cover.py
index 43cec0adb24..2e2ceb761a9 100644
--- a/homeassistant/components/velbus/cover.py
+++ b/homeassistant/components/velbus/cover.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 
 from typing import Any
 
-from velbusaio.channels import Channel as VelbusChannel
+from velbusaio.channels import Blind as VelbusBlind
 
 from homeassistant.components.cover import (
     ATTR_POSITION,
@@ -38,7 +38,9 @@ async def async_setup_entry(
 class VelbusCover(VelbusEntity, CoverEntity):
     """Representation a Velbus cover."""
 
-    def __init__(self, channel: VelbusChannel) -> None:
+    _channel: VelbusBlind
+
+    def __init__(self, channel: VelbusBlind) -> None:
         """Initialize the dimmer."""
         super().__init__(channel)
         if self._channel.support_position():
@@ -60,8 +62,7 @@ class VelbusCover(VelbusEntity, CoverEntity):
         None is unknown, 0 is closed, 100 is fully open
         Velbus: 100 = closed, 0 = open
         """
-        pos = self._channel.get_position()
-        return 100 - pos
+        return 100 - self._channel.get_position()
 
     async def async_open_cover(self, **kwargs: Any) -> None:
         """Open the cover."""
diff --git a/homeassistant/components/velbus/light.py b/homeassistant/components/velbus/light.py
index 2c6cd8d8776..ad0b150bf22 100644
--- a/homeassistant/components/velbus/light.py
+++ b/homeassistant/components/velbus/light.py
@@ -1,4 +1,14 @@
 """Support for Velbus light."""
+from __future__ import annotations
+
+from typing import Any
+
+from velbusaio.channels import (
+    Button as VelbusButton,
+    Channel as VelbusChannel,
+    Dimmer as VelbusDimmer,
+)
+
 from homeassistant.components.light import (
     ATTR_BRIGHTNESS,
     ATTR_FLASH,
@@ -10,16 +20,24 @@ from homeassistant.components.light import (
     SUPPORT_TRANSITION,
     LightEntity,
 )
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity import Entity
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
 from . import VelbusEntity
 from .const import DOMAIN
 
 
-async def async_setup_entry(hass, entry, async_add_entities):
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
     """Set up Velbus switch based on config_entry."""
     await hass.data[DOMAIN][entry.entry_id]["tsk"]
     cntrl = hass.data[DOMAIN][entry.entry_id]["cntrl"]
-    entities = []
+    entities: list[Entity] = []
     for channel in cntrl.get_all("light"):
         entities.append(VelbusLight(channel))
     for channel in cntrl.get_all("led"):
@@ -30,24 +48,25 @@ async def async_setup_entry(hass, entry, async_add_entities):
 class VelbusLight(VelbusEntity, LightEntity):
     """Representation of a Velbus light."""
 
+    _channel: VelbusDimmer
     _attr_supported_feature = SUPPORT_BRIGHTNESS | SUPPORT_TRANSITION
 
-    def __init__(self, channel):
+    def __init__(self, channel: VelbusDimmer) -> None:
         """Initialize the dimmer."""
         super().__init__(channel)
         self._attr_name = self._channel.get_name()
 
     @property
-    def is_on(self):
+    def is_on(self) -> bool:
         """Return true if the light is on."""
         return self._channel.is_on()
 
     @property
-    def brightness(self):
+    def brightness(self) -> int:
         """Return the brightness of the light."""
         return int((self._channel.get_dimmer_state() * 255) / 100)
 
-    async def async_turn_on(self, **kwargs):
+    async def async_turn_on(self, **kwargs: Any) -> None:
         """Instruct the Velbus light to turn on."""
         if ATTR_BRIGHTNESS in kwargs:
             # Make sure a low but non-zero value is not rounded down to zero
@@ -67,7 +86,7 @@ class VelbusLight(VelbusEntity, LightEntity):
             )
         await getattr(self._channel, attr)(*args)
 
-    async def async_turn_off(self, **kwargs):
+    async def async_turn_off(self, **kwargs: Any) -> None:
         """Instruct the velbus light to turn off."""
         attr, *args = (
             "set_dimmer_state",
@@ -80,25 +99,21 @@ class VelbusLight(VelbusEntity, LightEntity):
 class VelbusButtonLight(VelbusEntity, LightEntity):
     """Representation of a Velbus light."""
 
+    _channel: VelbusButton
     _attr_entity_registry_enabled_default = False
     _attr_supported_feature = SUPPORT_FLASH
 
-    def __init__(self, channel):
+    def __init__(self, channel: VelbusChannel) -> None:
         """Initialize the button light (led)."""
         super().__init__(channel)
         self._attr_name = f"LED {self._channel.get_name()}"
 
     @property
-    def is_on(self):
+    def is_on(self) -> Any:
         """Return true if the light is on."""
         return self._channel.is_on()
 
-    @property
-    def brightness(self):
-        """Return the brightness of the light."""
-        return int((self._channel.get_dimmer_state() * 255) / 100)
-
-    async def async_turn_on(self, **kwargs):
+    async def async_turn_on(self, **kwargs: Any) -> None:
         """Instruct the Velbus light to turn on."""
         if ATTR_FLASH in kwargs:
             if kwargs[ATTR_FLASH] == FLASH_LONG:
@@ -111,7 +126,7 @@ class VelbusButtonLight(VelbusEntity, LightEntity):
             attr, *args = "set_led_state", "on"
         await getattr(self._channel, attr)(*args)
 
-    async def async_turn_off(self, **kwargs):
+    async def async_turn_off(self, **kwargs: Any) -> None:
         """Instruct the velbus light to turn off."""
         attr, *args = "set_led_state", "off"
         await getattr(self._channel, attr)(*args)
diff --git a/homeassistant/components/velbus/sensor.py b/homeassistant/components/velbus/sensor.py
index 32f016b8ce3..8534a32080e 100644
--- a/homeassistant/components/velbus/sensor.py
+++ b/homeassistant/components/velbus/sensor.py
@@ -1,22 +1,31 @@
 """Support for Velbus sensors."""
 from __future__ import annotations
 
+from velbusaio.channels import ButtonCounter, LightSensor, SensorNumber, Temperature
+
 from homeassistant.components.sensor import (
     STATE_CLASS_MEASUREMENT,
     STATE_CLASS_TOTAL_INCREASING,
     SensorEntity,
 )
+from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     DEVICE_CLASS_ENERGY,
     DEVICE_CLASS_POWER,
     DEVICE_CLASS_TEMPERATURE,
 )
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
 from . import VelbusEntity
 from .const import DOMAIN
 
 
-async def async_setup_entry(hass, entry, async_add_entities):
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
     """Set up Velbus switch based on config_entry."""
     await hass.data[DOMAIN][entry.entry_id]["tsk"]
     cntrl = hass.data[DOMAIN][entry.entry_id]["cntrl"]
@@ -31,13 +40,19 @@ async def async_setup_entry(hass, entry, async_add_entities):
 class VelbusSensor(VelbusEntity, SensorEntity):
     """Representation of a sensor."""
 
-    def __init__(self, channel, counter=False):
+    _channel: ButtonCounter | Temperature | LightSensor | SensorNumber
+
+    def __init__(
+        self,
+        channel: ButtonCounter | Temperature | LightSensor | SensorNumber,
+        counter: bool = False,
+    ) -> None:
         """Initialize a sensor Velbus entity."""
         super().__init__(channel)
-        self._is_counter = counter
+        self._is_counter: bool = counter
 
     @property
-    def unique_id(self):
+    def unique_id(self) -> str:
         """Return unique ID for counter sensors."""
         unique_id = super().unique_id
         if self._is_counter:
@@ -45,7 +60,7 @@ class VelbusSensor(VelbusEntity, SensorEntity):
         return unique_id
 
     @property
-    def name(self):
+    def name(self) -> str:
         """Return the name for the sensor."""
         name = super().name
         if self._is_counter:
@@ -53,7 +68,7 @@ class VelbusSensor(VelbusEntity, SensorEntity):
         return name
 
     @property
-    def device_class(self):
+    def device_class(self) -> str | None:
         """Return the device class of the sensor."""
         if self._is_counter:
             return DEVICE_CLASS_ENERGY
@@ -64,28 +79,28 @@ class VelbusSensor(VelbusEntity, SensorEntity):
         return None
 
     @property
-    def native_value(self):
+    def native_value(self) -> float | int | None:
         """Return the state of the sensor."""
         if self._is_counter:
-            return self._channel.get_counter_state()
-        return self._channel.get_state()
+            return float(self._channel.get_counter_state())
+        return float(self._channel.get_state())
 
     @property
-    def native_unit_of_measurement(self):
+    def native_unit_of_measurement(self) -> str:
         """Return the unit this state is expressed in."""
         if self._is_counter:
-            return self._channel.get_counter_unit()
-        return self._channel.get_unit()
+            return str(self._channel.get_counter_unit())
+        return str(self._channel.get_unit())
 
     @property
-    def icon(self):
+    def icon(self) -> str | None:
         """Icon to use in the frontend."""
         if self._is_counter:
             return "mdi:counter"
         return None
 
     @property
-    def state_class(self):
+    def state_class(self) -> str:
         """Return the state class of this device."""
         if self._is_counter:
             return STATE_CLASS_TOTAL_INCREASING
diff --git a/homeassistant/components/velbus/switch.py b/homeassistant/components/velbus/switch.py
index c7b4a80f196..c3c4c8a5863 100644
--- a/homeassistant/components/velbus/switch.py
+++ b/homeassistant/components/velbus/switch.py
@@ -1,6 +1,8 @@
 """Support for Velbus switches."""
 from typing import Any
 
+from velbusaio.channels import Relay as VelbusRelay
+
 from homeassistant.components.switch import SwitchEntity
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
@@ -27,6 +29,8 @@ async def async_setup_entry(
 class VelbusSwitch(VelbusEntity, SwitchEntity):
     """Representation of a switch."""
 
+    _channel: VelbusRelay
+
     @property
     def is_on(self) -> bool:
         """Return true if the switch is on."""
diff --git a/mypy.ini b/mypy.ini
index 6859b8b2d48..91bca58ba6b 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1518,6 +1518,17 @@ no_implicit_optional = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.velbus.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+no_implicit_optional = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.vlc_telnet.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true