diff --git a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater_with_adjustable_temperature_setpoint.py b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater_with_adjustable_temperature_setpoint.py
index d79d2fca686..5807ccecd74 100644
--- a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater_with_adjustable_temperature_setpoint.py
+++ b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater_with_adjustable_temperature_setpoint.py
@@ -45,7 +45,7 @@ OVERKIZ_TO_PRESET_MODE: dict[str, str] = {
 PRESET_MODE_TO_OVERKIZ = {v: k for k, v in OVERKIZ_TO_PRESET_MODE.items()}
 
 # Map Overkiz HVAC modes to Home Assistant HVAC modes
-OVERKIZ_TO_HVAC_MODE: dict[str, str] = {
+OVERKIZ_TO_HVAC_MODE: dict[str, HVACMode] = {
     OverkizCommandParam.ON: HVACMode.HEAT,
     OverkizCommandParam.OFF: HVACMode.OFF,
     OverkizCommandParam.AUTO: HVACMode.AUTO,
@@ -83,7 +83,7 @@ class AtlanticElectricalHeaterWithAdjustableTemperatureSetpoint(
         )
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         states = self.device.states
         if (state := states[OverkizState.CORE_OPERATING_MODE]) and state.value_as_str:
diff --git a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_towel_dryer.py b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_towel_dryer.py
index c8e4920a113..0c378d088c5 100644
--- a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_towel_dryer.py
+++ b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_towel_dryer.py
@@ -20,7 +20,7 @@ from ..entity import OverkizEntity
 
 PRESET_DRYING = "drying"
 
-OVERKIZ_TO_HVAC_MODE: dict[str, str] = {
+OVERKIZ_TO_HVAC_MODE: dict[str, HVACMode] = {
     OverkizCommandParam.EXTERNAL: HVACMode.HEAT,  # manu
     OverkizCommandParam.INTERNAL: HVACMode.AUTO,  # prog
     OverkizCommandParam.STANDBY: HVACMode.OFF,
@@ -62,7 +62,7 @@ class AtlanticElectricalTowelDryer(OverkizEntity, ClimateEntity):
             self._attr_supported_features |= ClimateEntityFeature.PRESET_MODE
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         if OverkizState.CORE_OPERATING_MODE in self.device.states:
             return OVERKIZ_TO_HVAC_MODE[
@@ -71,7 +71,7 @@ class AtlanticElectricalTowelDryer(OverkizEntity, ClimateEntity):
 
         return HVACMode.OFF
 
-    async def async_set_hvac_mode(self, hvac_mode: str) -> None:
+    async def async_set_hvac_mode(self, hvac_mode: HVACMode) -> None:
         """Set new target hvac mode."""
         await self.executor.async_execute_command(
             OverkizCommand.SET_TOWEL_DRYER_OPERATING_MODE,
diff --git a/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_heating_zone.py b/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_heating_zone.py
index b6835d93ebb..7722269a48b 100644
--- a/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_heating_zone.py
+++ b/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_heating_zone.py
@@ -21,7 +21,7 @@ from ..const import DOMAIN
 from ..coordinator import OverkizDataUpdateCoordinator
 from ..entity import OverkizEntity
 
-OVERKIZ_TO_HVAC_MODE: dict[str, str] = {
+OVERKIZ_TO_HVAC_MODE: dict[str, HVACMode] = {
     OverkizCommandParam.AUTO: HVACMode.AUTO,
     OverkizCommandParam.ECO: HVACMode.AUTO,
     OverkizCommandParam.MANU: HVACMode.HEAT,
@@ -101,7 +101,7 @@ class AtlanticPassAPCHeatingZone(OverkizEntity, ClimateEntity):
         return None
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         return OVERKIZ_TO_HVAC_MODE[
             cast(str, self.executor.select_state(OverkizState.IO_PASS_APC_HEATING_MODE))
@@ -135,7 +135,7 @@ class AtlanticPassAPCHeatingZone(OverkizEntity, ClimateEntity):
             OverkizCommand.REFRESH_PASS_APC_HEATING_PROFILE
         )
 
-    async def async_set_hvac_mode(self, hvac_mode: str) -> None:
+    async def async_set_hvac_mode(self, hvac_mode: HVACMode) -> None:
         """Set new target hvac mode."""
         await self.async_set_heating_mode(HVAC_MODE_TO_OVERKIZ[hvac_mode])
 
diff --git a/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_zone_control.py b/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_zone_control.py
index 33c1f0c4a2a..74f7637b997 100644
--- a/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_zone_control.py
+++ b/homeassistant/components/overkiz/climate_entities/atlantic_pass_apc_zone_control.py
@@ -8,7 +8,7 @@ from homeassistant.const import UnitOfTemperature
 
 from ..entity import OverkizEntity
 
-OVERKIZ_TO_HVAC_MODE: dict[str, str] = {
+OVERKIZ_TO_HVAC_MODE: dict[str, HVACMode] = {
     OverkizCommandParam.HEATING: HVACMode.HEAT,
     OverkizCommandParam.DRYING: HVACMode.DRY,
     OverkizCommandParam.COOLING: HVACMode.COOL,
@@ -25,7 +25,7 @@ class AtlanticPassAPCZoneControl(OverkizEntity, ClimateEntity):
     _attr_temperature_unit = UnitOfTemperature.CELSIUS
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         return OVERKIZ_TO_HVAC_MODE[
             cast(
@@ -33,7 +33,7 @@ class AtlanticPassAPCZoneControl(OverkizEntity, ClimateEntity):
             )
         ]
 
-    async def async_set_hvac_mode(self, hvac_mode: str) -> None:
+    async def async_set_hvac_mode(self, hvac_mode: HVACMode) -> None:
         """Set new target hvac mode."""
         await self.executor.async_execute_command(
             OverkizCommand.SET_PASS_APC_OPERATING_MODE, HVAC_MODE_TO_OVERKIZ[hvac_mode]
diff --git a/homeassistant/components/overkiz/climate_entities/somfy_thermostat.py b/homeassistant/components/overkiz/climate_entities/somfy_thermostat.py
index aaae64e0454..7409b5307cf 100644
--- a/homeassistant/components/overkiz/climate_entities/somfy_thermostat.py
+++ b/homeassistant/components/overkiz/climate_entities/somfy_thermostat.py
@@ -74,7 +74,7 @@ class SomfyThermostat(OverkizEntity, ClimateEntity):
         )
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         return OVERKIZ_TO_HVAC_MODES[
             cast(