diff --git a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater.py b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater.py
index 2558c7e8e8e..0a397e9f2ad 100644
--- a/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater.py
+++ b/homeassistant/components/overkiz/climate_entities/atlantic_electrical_heater.py
@@ -5,26 +5,23 @@ from typing import cast
 
 from pyoverkiz.enums import OverkizCommand, OverkizCommandParam, OverkizState
 
-from homeassistant.components.climate import (
-    HVAC_MODE_OFF,
-    ClimateEntity,
-    ClimateEntityFeature,
-)
+from homeassistant.components.climate import ClimateEntity
 from homeassistant.components.climate.const import (
-    HVAC_MODE_HEAT,
     PRESET_COMFORT,
     PRESET_ECO,
     PRESET_NONE,
+    ClimateEntityFeature,
+    HVACMode,
 )
 from homeassistant.components.overkiz.entity import OverkizEntity
 from homeassistant.const import TEMP_CELSIUS
 
 PRESET_FROST_PROTECTION = "frost_protection"
 
-OVERKIZ_TO_HVAC_MODES: dict[str, str] = {
-    OverkizCommandParam.ON: HVAC_MODE_HEAT,
-    OverkizCommandParam.COMFORT: HVAC_MODE_HEAT,
-    OverkizCommandParam.OFF: HVAC_MODE_OFF,
+OVERKIZ_TO_HVAC_MODES: dict[str, HVACMode] = {
+    OverkizCommandParam.ON: HVACMode.HEAT,
+    OverkizCommandParam.COMFORT: HVACMode.HEAT,
+    OverkizCommandParam.OFF: HVACMode.OFF,
 }
 HVAC_MODES_TO_OVERKIZ = {v: k for k, v in OVERKIZ_TO_HVAC_MODES.items()}
 
@@ -47,13 +44,13 @@ class AtlanticElectricalHeater(OverkizEntity, ClimateEntity):
     _attr_temperature_unit = TEMP_CELSIUS
 
     @property
-    def hvac_mode(self) -> str:
+    def hvac_mode(self) -> HVACMode:
         """Return hvac operation ie. heat, cool mode."""
         return OVERKIZ_TO_HVAC_MODES[
             cast(str, self.executor.select_state(OverkizState.CORE_ON_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_HEATING_LEVEL, HVAC_MODES_TO_OVERKIZ[hvac_mode]