diff --git a/homeassistant/components/incomfort/binary_sensor.py b/homeassistant/components/incomfort/binary_sensor.py
index 45da990d44f..2696491422b 100644
--- a/homeassistant/components/incomfort/binary_sensor.py
+++ b/homeassistant/components/incomfort/binary_sensor.py
@@ -13,6 +13,7 @@ from homeassistant.components.binary_sensor import (
     BinarySensorEntity,
     BinarySensorEntityDescription,
 )
+from homeassistant.const import EntityCategory
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
@@ -29,6 +30,7 @@ class IncomfortBinarySensorEntityDescription(BinarySensorEntityDescription):
 
     value_key: str
     extra_state_attributes_fn: Callable[[dict[str, Any]], dict[str, Any]] | None = None
+    entity_category: EntityCategory = EntityCategory.DIAGNOSTIC
 
 
 SENSOR_TYPES: tuple[IncomfortBinarySensorEntityDescription, ...] = (
diff --git a/homeassistant/components/incomfort/climate.py b/homeassistant/components/incomfort/climate.py
index 545666a826f..756e14fc545 100644
--- a/homeassistant/components/incomfort/climate.py
+++ b/homeassistant/components/incomfort/climate.py
@@ -12,7 +12,7 @@ from homeassistant.components.climate import (
     HVACAction,
     HVACMode,
 )
-from homeassistant.const import ATTR_TEMPERATURE, UnitOfTemperature
+from homeassistant.const import ATTR_TEMPERATURE, EntityCategory, UnitOfTemperature
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.device_registry import DeviceInfo
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
@@ -44,6 +44,7 @@ async def async_setup_entry(
 class InComfortClimate(IncomfortEntity, ClimateEntity):
     """Representation of an InComfort/InTouch climate device."""
 
+    _attr_entity_category = EntityCategory.CONFIG
     _attr_min_temp = 5.0
     _attr_max_temp = 30.0
     _attr_name = None
diff --git a/homeassistant/components/incomfort/sensor.py b/homeassistant/components/incomfort/sensor.py
index e3cc52fb3a7..793a2f0450c 100644
--- a/homeassistant/components/incomfort/sensor.py
+++ b/homeassistant/components/incomfort/sensor.py
@@ -13,7 +13,7 @@ from homeassistant.components.sensor import (
     SensorEntityDescription,
     SensorStateClass,
 )
-from homeassistant.const import UnitOfPressure, UnitOfTemperature
+from homeassistant.const import EntityCategory, UnitOfPressure, UnitOfTemperature
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.typing import StateType
@@ -31,6 +31,7 @@ class IncomfortSensorEntityDescription(SensorEntityDescription):
 
     value_key: str
     extra_key: str | None = None
+    entity_category = EntityCategory.DIAGNOSTIC
 
 
 SENSOR_TYPES: tuple[IncomfortSensorEntityDescription, ...] = (
diff --git a/homeassistant/components/incomfort/water_heater.py b/homeassistant/components/incomfort/water_heater.py
index 5b676b3b7ff..0ab4a6a06b8 100644
--- a/homeassistant/components/incomfort/water_heater.py
+++ b/homeassistant/components/incomfort/water_heater.py
@@ -8,7 +8,7 @@ from typing import Any
 from incomfortclient import Heater as InComfortHeater
 
 from homeassistant.components.water_heater import WaterHeaterEntity
-from homeassistant.const import UnitOfTemperature
+from homeassistant.const import EntityCategory, UnitOfTemperature
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
@@ -37,6 +37,7 @@ async def async_setup_entry(
 class IncomfortWaterHeater(IncomfortBoilerEntity, WaterHeaterEntity):
     """Representation of an InComfort/Intouch water_heater device."""
 
+    _attr_entity_category = EntityCategory.DIAGNOSTIC
     _attr_min_temp = 30.0
     _attr_max_temp = 80.0
     _attr_name = None
diff --git a/tests/components/incomfort/snapshots/test_binary_sensor.ambr b/tests/components/incomfort/snapshots/test_binary_sensor.ambr
index 2f2319b6a44..fe0d8edd0f0 100644
--- a/tests/components/incomfort/snapshots/test_binary_sensor.ambr
+++ b/tests/components/incomfort/snapshots/test_binary_sensor.ambr
@@ -10,7 +10,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_burner',
     'has_entity_name': True,
     'hidden_by': None,
@@ -57,7 +57,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_fault',
     'has_entity_name': True,
     'hidden_by': None,
@@ -105,7 +105,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_hot_water_tap',
     'has_entity_name': True,
     'hidden_by': None,
@@ -152,7 +152,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_pump',
     'has_entity_name': True,
     'hidden_by': None,
@@ -199,7 +199,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_burner',
     'has_entity_name': True,
     'hidden_by': None,
@@ -246,7 +246,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_fault',
     'has_entity_name': True,
     'hidden_by': None,
@@ -294,7 +294,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_hot_water_tap',
     'has_entity_name': True,
     'hidden_by': None,
@@ -341,7 +341,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_pump',
     'has_entity_name': True,
     'hidden_by': None,
@@ -388,7 +388,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_burner',
     'has_entity_name': True,
     'hidden_by': None,
@@ -435,7 +435,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_fault',
     'has_entity_name': True,
     'hidden_by': None,
@@ -483,7 +483,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_hot_water_tap',
     'has_entity_name': True,
     'hidden_by': None,
@@ -530,7 +530,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_pump',
     'has_entity_name': True,
     'hidden_by': None,
@@ -577,7 +577,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_burner',
     'has_entity_name': True,
     'hidden_by': None,
@@ -624,7 +624,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_fault',
     'has_entity_name': True,
     'hidden_by': None,
@@ -672,7 +672,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_hot_water_tap',
     'has_entity_name': True,
     'hidden_by': None,
@@ -719,7 +719,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_pump',
     'has_entity_name': True,
     'hidden_by': None,
@@ -766,7 +766,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_burner',
     'has_entity_name': True,
     'hidden_by': None,
@@ -813,7 +813,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_fault',
     'has_entity_name': True,
     'hidden_by': None,
@@ -861,7 +861,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_hot_water_tap',
     'has_entity_name': True,
     'hidden_by': None,
@@ -908,7 +908,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'binary_sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'binary_sensor.boiler_pump',
     'has_entity_name': True,
     'hidden_by': None,
diff --git a/tests/components/incomfort/snapshots/test_climate.ambr b/tests/components/incomfort/snapshots/test_climate.ambr
index bd940bbc2ce..e0e8b9562dd 100644
--- a/tests/components/incomfort/snapshots/test_climate.ambr
+++ b/tests/components/incomfort/snapshots/test_climate.ambr
@@ -16,7 +16,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'climate',
-    'entity_category': None,
+    'entity_category': <EntityCategory.CONFIG: 'config'>,
     'entity_id': 'climate.thermostat_1',
     'has_entity_name': True,
     'hidden_by': None,
@@ -82,7 +82,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'climate',
-    'entity_category': None,
+    'entity_category': <EntityCategory.CONFIG: 'config'>,
     'entity_id': 'climate.thermostat_1',
     'has_entity_name': True,
     'hidden_by': None,
@@ -148,7 +148,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'climate',
-    'entity_category': None,
+    'entity_category': <EntityCategory.CONFIG: 'config'>,
     'entity_id': 'climate.thermostat_1',
     'has_entity_name': True,
     'hidden_by': None,
@@ -214,7 +214,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'climate',
-    'entity_category': None,
+    'entity_category': <EntityCategory.CONFIG: 'config'>,
     'entity_id': 'climate.thermostat_1',
     'has_entity_name': True,
     'hidden_by': None,
diff --git a/tests/components/incomfort/snapshots/test_sensor.ambr b/tests/components/incomfort/snapshots/test_sensor.ambr
index 8c9ea60f455..a69a64d964e 100644
--- a/tests/components/incomfort/snapshots/test_sensor.ambr
+++ b/tests/components/incomfort/snapshots/test_sensor.ambr
@@ -12,7 +12,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'sensor.boiler_pressure',
     'has_entity_name': True,
     'hidden_by': None,
@@ -63,7 +63,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'sensor.boiler_tap_temperature',
     'has_entity_name': True,
     'hidden_by': None,
@@ -115,7 +115,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'sensor',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'sensor.boiler_temperature',
     'has_entity_name': True,
     'hidden_by': None,
diff --git a/tests/components/incomfort/snapshots/test_water_heater.ambr b/tests/components/incomfort/snapshots/test_water_heater.ambr
index 06b0d0c1e52..d2cd955a9fc 100644
--- a/tests/components/incomfort/snapshots/test_water_heater.ambr
+++ b/tests/components/incomfort/snapshots/test_water_heater.ambr
@@ -13,7 +13,7 @@
     'device_id': <ANY>,
     'disabled_by': None,
     'domain': 'water_heater',
-    'entity_category': None,
+    'entity_category': <EntityCategory.DIAGNOSTIC: 'diagnostic'>,
     'entity_id': 'water_heater.boiler',
     'has_entity_name': True,
     'hidden_by': None,