diff --git a/homeassistant/components/homematicip_cloud/sensor.py b/homeassistant/components/homematicip_cloud/sensor.py
index b4eb89f06c8..04fba2cfd92 100644
--- a/homeassistant/components/homematicip_cloud/sensor.py
+++ b/homeassistant/components/homematicip_cloud/sensor.py
@@ -177,10 +177,10 @@ class HomematicipHeatingThermostat(HomematicipGenericEntity, SensorEntity):
         return "mdi:radiator"
 
     @property
-    def native_value(self) -> int:
+    def native_value(self) -> int | None:
         """Return the state of the radiator valve."""
         if self._device.valveState != ValveState.ADAPTION_DONE:
-            return self._device.valveState
+            return None
         return round(self._device.valvePosition * 100)
 
 
diff --git a/tests/components/homematicip_cloud/test_sensor.py b/tests/components/homematicip_cloud/test_sensor.py
index 33da0f217ae..b4da2a83c38 100644
--- a/tests/components/homematicip_cloud/test_sensor.py
+++ b/tests/components/homematicip_cloud/test_sensor.py
@@ -29,6 +29,7 @@ from homeassistant.const import (
     PERCENTAGE,
     POWER_WATT,
     SPEED_KILOMETERS_PER_HOUR,
+    STATE_UNKNOWN,
     TEMP_CELSIUS,
 )
 from homeassistant.setup import async_setup_component
@@ -82,7 +83,7 @@ async def test_hmip_heating_thermostat(hass, default_mock_hap_factory):
 
     await async_manipulate_test_data(hass, hmip_device, "valveState", "nn")
     ha_state = hass.states.get(entity_id)
-    assert ha_state.state == "nn"
+    assert ha_state.state == STATE_UNKNOWN
 
     await async_manipulate_test_data(
         hass, hmip_device, "valveState", ValveState.ADAPTION_DONE