diff --git a/homeassistant/components/refoss/sensor.py b/homeassistant/components/refoss/sensor.py
index 018c438ba3c..3857b401d0d 100644
--- a/homeassistant/components/refoss/sensor.py
+++ b/homeassistant/components/refoss/sensor.py
@@ -35,12 +35,12 @@ from .const import (
 from .entity import RefossEntity
 
 
-@dataclass(frozen=True)
+@dataclass(frozen=True, kw_only=True)
 class RefossSensorEntityDescription(SensorEntityDescription):
     """Describes Refoss sensor entity."""
 
-    subkey: str | None = None
-    fn: Callable[[float], float] | None = None
+    subkey: str
+    fn: Callable[[float], float] = lambda x: x
 
 
 SENSORS: dict[str, tuple[RefossSensorEntityDescription, ...]] = {
@@ -50,10 +50,10 @@ SENSORS: dict[str, tuple[RefossSensorEntityDescription, ...]] = {
             translation_key="power",
             device_class=SensorDeviceClass.POWER,
             state_class=SensorStateClass.MEASUREMENT,
-            native_unit_of_measurement=UnitOfPower.WATT,
+            native_unit_of_measurement=UnitOfPower.KILO_WATT,
+            suggested_unit_of_measurement=UnitOfPower.WATT,
             suggested_display_precision=2,
             subkey="power",
-            fn=lambda x: x / 1000.0,
         ),
         RefossSensorEntityDescription(
             key="voltage",
@@ -115,24 +115,25 @@ async def async_setup_entry(
     """Set up the Refoss device from a config entry."""
 
     @callback
-    def init_device(coordinator):
+    def init_device(coordinator: RefossDataUpdateCoordinator) -> None:
         """Register the device."""
         device = coordinator.device
 
         if not isinstance(device, ElectricityXMix):
             return
-        descriptions = SENSORS.get(device.device_type)
-        new_entities = []
-        for channel in device.channels:
-            for description in descriptions:
-                entity = RefossSensor(
-                    coordinator=coordinator,
-                    channel=channel,
-                    description=description,
-                )
-                new_entities.append(entity)
+        descriptions: tuple[RefossSensorEntityDescription, ...] = SENSORS.get(
+            device.device_type, ()
+        )
 
-        async_add_entities(new_entities)
+        async_add_entities(
+            RefossSensor(
+                coordinator=coordinator,
+                channel=channel,
+                description=description,
+            )
+            for channel in device.channels
+            for description in descriptions
+        )
 
     for coordinator in hass.data[DOMAIN][COORDINATORS]:
         init_device(coordinator)
@@ -169,6 +170,4 @@ class RefossSensor(RefossEntity, SensorEntity):
         )
         if value is None:
             return None
-        if self.entity_description.fn is not None:
-            return self.entity_description.fn(value)
-        return value
+        return self.entity_description.fn(value)