diff --git a/.strict-typing b/.strict-typing
index 5b4721d7e6e..625f80e38c0 100644
--- a/.strict-typing
+++ b/.strict-typing
@@ -455,6 +455,7 @@ homeassistant.components.russound_rio.*
 homeassistant.components.ruuvi_gateway.*
 homeassistant.components.ruuvitag_ble.*
 homeassistant.components.samsungtv.*
+homeassistant.components.saunum.*
 homeassistant.components.scene.*
 homeassistant.components.schedule.*
 homeassistant.components.schlage.*
diff --git a/homeassistant/components/saunum/climate.py b/homeassistant/components/saunum/climate.py
index f90703edea2..85fa57e369d 100644
--- a/homeassistant/components/saunum/climate.py
+++ b/homeassistant/components/saunum/climate.py
@@ -17,7 +17,7 @@ from homeassistant.components.climate import (
     HVACAction,
     HVACMode,
 )
-from homeassistant.const import ATTR_TEMPERATURE, UnitOfTemperature
+from homeassistant.const import ATTR_TEMPERATURE, PRECISION_WHOLE, UnitOfTemperature
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
 from homeassistant.helpers.entity_platform import AddConfigEntryEntitiesCallback
@@ -57,6 +57,8 @@ class LeilSaunaClimate(LeilSaunaEntity, ClimateEntity):
         ClimateEntityFeature.TARGET_TEMPERATURE | ClimateEntityFeature.FAN_MODE
     )
     _attr_temperature_unit = UnitOfTemperature.CELSIUS
+    _attr_precision = PRECISION_WHOLE
+    _attr_target_temperature_step = 1.0
     _attr_min_temp = MIN_TEMPERATURE
     _attr_max_temp = MAX_TEMPERATURE
     _attr_fan_modes = [FAN_OFF, FAN_LOW, FAN_MEDIUM, FAN_HIGH]
@@ -143,10 +145,18 @@ class LeilSaunaClimate(LeilSaunaEntity, ClimateEntity):
         """Set new fan mode."""
         if not self.coordinator.data.session_active:
             raise ServiceValidationError(
-                "Cannot change fan mode when sauna session is not active",
                 translation_domain=DOMAIN,
                 translation_key="session_not_active",
             )
 
-        await self.coordinator.client.async_set_fan_speed(FAN_MODE_TO_SPEED[fan_mode])
+        try:
+            await self.coordinator.client.async_set_fan_speed(
+                FAN_MODE_TO_SPEED[fan_mode]
+            )
+        except SaunumException as err:
+            raise HomeAssistantError(
+                translation_domain=DOMAIN,
+                translation_key="set_fan_mode_failed",
+            ) from err
+
         await self.coordinator.async_request_refresh()
diff --git a/homeassistant/components/saunum/light.py b/homeassistant/components/saunum/light.py
index 179672b4737..30be9924f08 100644
--- a/homeassistant/components/saunum/light.py
+++ b/homeassistant/components/saunum/light.py
@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from pysaunum import SaunumException
 
@@ -15,6 +15,9 @@ from . import LeilSaunaConfigEntry
 from .const import DOMAIN
 from .entity import LeilSaunaEntity
 
+if TYPE_CHECKING:
+    from .coordinator import LeilSaunaCoordinator
+
 PARALLEL_UPDATES = 1
 
 
@@ -35,7 +38,7 @@ class LeilSaunaLight(LeilSaunaEntity, LightEntity):
     _attr_color_mode = ColorMode.ONOFF
     _attr_supported_color_modes = {ColorMode.ONOFF}
 
-    def __init__(self, coordinator) -> None:
+    def __init__(self, coordinator: LeilSaunaCoordinator) -> None:
         """Initialize the light entity."""
         super().__init__(coordinator)
         # Override unique_id to differentiate from climate entity
diff --git a/homeassistant/components/saunum/manifest.json b/homeassistant/components/saunum/manifest.json
index cc5f943004e..8b86d55323c 100644
--- a/homeassistant/components/saunum/manifest.json
+++ b/homeassistant/components/saunum/manifest.json
@@ -7,6 +7,6 @@
   "integration_type": "device",
   "iot_class": "local_polling",
   "loggers": ["pysaunum"],
-  "quality_scale": "gold",
+  "quality_scale": "platinum",
   "requirements": ["pysaunum==0.2.0"]
 }
diff --git a/homeassistant/components/saunum/number.py b/homeassistant/components/saunum/number.py
index cd12df201cc..0a59127ffd6 100644
--- a/homeassistant/components/saunum/number.py
+++ b/homeassistant/components/saunum/number.py
@@ -133,11 +133,7 @@ class LeilSaunaNumber(LeilSaunaEntity, NumberEntity):
         except SaunumException as err:
             raise HomeAssistantError(
                 translation_domain=DOMAIN,
-                translation_key="set_value_failed",
-                translation_placeholders={
-                    "entity": self.entity_description.key,
-                    "value": str(value),
-                },
+                translation_key=f"set_{self.entity_description.key}_failed",
             ) from err
 
         await self.coordinator.async_request_refresh()
diff --git a/homeassistant/components/saunum/quality_scale.yaml b/homeassistant/components/saunum/quality_scale.yaml
index 546bb34ee51..4a7d29777b4 100644
--- a/homeassistant/components/saunum/quality_scale.yaml
+++ b/homeassistant/components/saunum/quality_scale.yaml
@@ -77,4 +77,4 @@ rules:
   inject-websession:
     status: exempt
     comment: Integration uses Modbus TCP protocol and does not make HTTP requests.
-  strict-typing: todo
+  strict-typing: done
diff --git a/homeassistant/components/saunum/strings.json b/homeassistant/components/saunum/strings.json
index e72fad37fa6..a2c4d8e51db 100644
--- a/homeassistant/components/saunum/strings.json
+++ b/homeassistant/components/saunum/strings.json
@@ -89,6 +89,12 @@
     "session_not_active": {
       "message": "Cannot change fan mode when sauna session is not active"
     },
+    "set_fan_duration_failed": {
+      "message": "Failed to set fan duration"
+    },
+    "set_fan_mode_failed": {
+      "message": "Failed to set fan mode"
+    },
     "set_hvac_mode_failed": {
       "message": "Failed to set HVAC mode to {hvac_mode}"
     },
@@ -98,11 +104,11 @@
     "set_light_on_failed": {
       "message": "Failed to turn on light"
     },
+    "set_sauna_duration_failed": {
+      "message": "Failed to set sauna duration"
+    },
     "set_temperature_failed": {
       "message": "Failed to set temperature to {temperature}"
-    },
-    "set_value_failed": {
-      "message": "Failed to set {entity} to {value}"
     }
   }
 }
diff --git a/mypy.ini b/mypy.ini
index 35f9cbd7a05..da80d719894 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -4306,6 +4306,16 @@ disallow_untyped_defs = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.saunum.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.scene.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true
diff --git a/tests/components/saunum/snapshots/test_climate.ambr b/tests/components/saunum/snapshots/test_climate.ambr
index a52f7d690a2..47a9b17cc88 100644
--- a/tests/components/saunum/snapshots/test_climate.ambr
+++ b/tests/components/saunum/snapshots/test_climate.ambr
@@ -17,6 +17,7 @@
       ]),
       'max_temp': 100,
       'min_temp': 40,
+      'target_temp_step': 1.0,
     }),
     'config_entry_id': <ANY>,
     'config_subentry_id': <ANY>,
@@ -51,7 +52,7 @@
 # name: test_entities[climate.saunum_leil-state]
   StateSnapshot({
     'attributes': ReadOnlyDict({
-      'current_temperature': 75.0,
+      'current_temperature': 75,
       'fan_mode': 'medium',
       'fan_modes': list([
         'off',
@@ -68,6 +69,7 @@
       'max_temp': 100,
       'min_temp': 40,
       'supported_features': <ClimateEntityFeature: 9>,
+      'target_temp_step': 1.0,
       'temperature': 80,
     }),
     'context': <ANY>,
diff --git a/tests/components/saunum/test_climate.py b/tests/components/saunum/test_climate.py
index 73b72b7923a..269dba0907b 100644
--- a/tests/components/saunum/test_climate.py
+++ b/tests/components/saunum/test_climate.py
@@ -378,3 +378,33 @@ async def test_fan_mode_session_not_active_error(
             {ATTR_ENTITY_ID: entity_id, ATTR_FAN_MODE: FAN_LOW},
             blocking=True,
         )
+
+
+@pytest.mark.usefixtures("init_integration")
+async def test_fan_mode_error_handling(
+    hass: HomeAssistant,
+    mock_saunum_client,
+) -> None:
+    """Test error handling when setting fan mode fails."""
+    entity_id = "climate.saunum_leil"
+
+    # Ensure session is active
+    mock_saunum_client.async_get_data.return_value.session_active = True
+
+    # Make the client method raise an exception
+    mock_saunum_client.async_set_fan_speed.side_effect = SaunumException(
+        "Communication error"
+    )
+
+    # Try to call the service and expect HomeAssistantError
+    with pytest.raises(HomeAssistantError) as exc_info:
+        await hass.services.async_call(
+            CLIMATE_DOMAIN,
+            SERVICE_SET_FAN_MODE,
+            {ATTR_ENTITY_ID: entity_id, ATTR_FAN_MODE: FAN_LOW},
+            blocking=True,
+        )
+
+    # Verify the exception has the correct translation key
+    assert exc_info.value.translation_key == "set_fan_mode_failed"
+    assert exc_info.value.translation_domain == "saunum"
diff --git a/tests/components/saunum/test_sensor.py b/tests/components/saunum/test_sensor.py
index 9fa223ecaa0..dc28812e87c 100644
--- a/tests/components/saunum/test_sensor.py
+++ b/tests/components/saunum/test_sensor.py
@@ -52,7 +52,7 @@ async def test_sensor_not_created_when_value_is_none(
     assert await hass.config_entries.async_setup(mock_config_entry.entry_id)
     await hass.async_block_till_done()
 
-    assert hass.states.get("sensor.saunum_leil_temperature") is None
+    assert hass.states.get("sensor.saunum_leil_current_temperature") is None
     assert hass.states.get("sensor.saunum_leil_heater_elements_active") is None
     assert hass.states.get("sensor.saunum_leil_on_time") is None