diff --git a/homeassistant/components/energy/sensor.py b/homeassistant/components/energy/sensor.py
index 1c42ea5a050..e974035cbd6 100644
--- a/homeassistant/components/energy/sensor.py
+++ b/homeassistant/components/energy/sensor.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 
 from dataclasses import dataclass
 from functools import partial
+import logging
 from typing import Any, Final, Literal, TypeVar, cast
 
 from homeassistant.components.sensor import (
@@ -11,6 +12,11 @@ from homeassistant.components.sensor import (
     STATE_CLASS_MEASUREMENT,
     SensorEntity,
 )
+from homeassistant.const import (
+    ATTR_UNIT_OF_MEASUREMENT,
+    ENERGY_KILO_WATT_HOUR,
+    ENERGY_WATT_HOUR,
+)
 from homeassistant.core import HomeAssistant, State, callback, split_entity_id
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.event import async_track_state_change_event
@@ -20,6 +26,8 @@ import homeassistant.util.dt as dt_util
 from .const import DOMAIN
 from .data import EnergyManager, async_get_manager
 
+_LOGGER = logging.getLogger(__name__)
+
 
 async def async_setup_platform(
     hass: HomeAssistant,
@@ -188,6 +196,12 @@ class EnergyCostSensor(SensorEntity):
                 energy_price = float(energy_price_state.state)
             except ValueError:
                 return
+
+            if energy_price_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT, "").endswith(
+                f"/{ENERGY_WATT_HOUR}"
+            ):
+                energy_price *= 1000.0
+
         else:
             energy_price_state = None
             energy_price = cast(float, self._flow["number_energy_price"])
@@ -197,6 +211,16 @@ class EnergyCostSensor(SensorEntity):
             self._reset(energy_state)
             return
 
+        energy_unit = energy_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+
+        if energy_unit == ENERGY_WATT_HOUR:
+            energy_price /= 1000
+        elif energy_unit != ENERGY_KILO_WATT_HOUR:
+            _LOGGER.warning(
+                "Found unexpected unit %s for %s", energy_unit, energy_state.entity_id
+            )
+            return
+
         if (
             energy_state.attributes[ATTR_LAST_RESET]
             != self._last_energy_sensor_state.attributes[ATTR_LAST_RESET]
diff --git a/tests/components/energy/test_sensor.py b/tests/components/energy/test_sensor.py
index f3af93c06c1..978b21e1919 100644
--- a/tests/components/energy/test_sensor.py
+++ b/tests/components/energy/test_sensor.py
@@ -16,6 +16,8 @@ from homeassistant.const import (
     ATTR_DEVICE_CLASS,
     ATTR_UNIT_OF_MEASUREMENT,
     DEVICE_CLASS_MONETARY,
+    ENERGY_KILO_WATT_HOUR,
+    ENERGY_WATT_HOUR,
 )
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -133,7 +135,9 @@ async def test_cost_sensor_price_entity(
     # Optionally initialize dependent entities
     if initial_energy is not None:
         hass.states.async_set(
-            usage_sensor_entity_id, initial_energy, {"last_reset": last_reset}
+            usage_sensor_entity_id,
+            initial_energy,
+            {"last_reset": last_reset, ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR},
         )
     hass.states.async_set("sensor.energy_price", "1")
 
@@ -152,7 +156,12 @@ async def test_cost_sensor_price_entity(
     if initial_energy is None:
         with patch("homeassistant.util.dt.utcnow", return_value=now):
             hass.states.async_set(
-                usage_sensor_entity_id, "0", {"last_reset": last_reset}
+                usage_sensor_entity_id,
+                "0",
+                {
+                    "last_reset": last_reset,
+                    ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR,
+                },
             )
             await hass.async_block_till_done()
 
@@ -169,7 +178,11 @@ async def test_cost_sensor_price_entity(
     # # assert entry.unique_id == "energy_energy_consumption cost"
 
     # Energy use bumped to 10 kWh
-    hass.states.async_set(usage_sensor_entity_id, "10", {"last_reset": last_reset})
+    hass.states.async_set(
+        usage_sensor_entity_id,
+        "10",
+        {"last_reset": last_reset, ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR},
+    )
     await hass.async_block_till_done()
     state = hass.states.get(cost_sensor_entity_id)
     assert state.state == "10.0"  # 0 EUR + (10-0) kWh * 1 EUR/kWh = 10 EUR
@@ -189,7 +202,11 @@ async def test_cost_sensor_price_entity(
     assert state.state == "10.0"  # 10 EUR + (10-10) kWh * 2 EUR/kWh = 10 EUR
 
     # Additional consumption is using the new price
-    hass.states.async_set(usage_sensor_entity_id, "14.5", {"last_reset": last_reset})
+    hass.states.async_set(
+        usage_sensor_entity_id,
+        "14.5",
+        {"last_reset": last_reset, ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR},
+    )
     await hass.async_block_till_done()
     state = hass.states.get(cost_sensor_entity_id)
     assert state.state == "19.0"  # 10 EUR + (14.5-10) kWh * 2 EUR/kWh = 19 EUR
@@ -202,13 +219,21 @@ async def test_cost_sensor_price_entity(
 
     # Energy sensor is reset, with start point at 4kWh
     last_reset = (now + timedelta(seconds=1)).isoformat()
-    hass.states.async_set(usage_sensor_entity_id, "4", {"last_reset": last_reset})
+    hass.states.async_set(
+        usage_sensor_entity_id,
+        "4",
+        {"last_reset": last_reset, ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR},
+    )
     await hass.async_block_till_done()
     state = hass.states.get(cost_sensor_entity_id)
     assert state.state == "0.0"  # 0 EUR + (4-4) kWh * 2 EUR/kWh = 0 EUR
 
     # Energy use bumped to 10 kWh
-    hass.states.async_set(usage_sensor_entity_id, "10", {"last_reset": last_reset})
+    hass.states.async_set(
+        usage_sensor_entity_id,
+        "10",
+        {"last_reset": last_reset, ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR},
+    )
     await hass.async_block_till_done()
     state = hass.states.get(cost_sensor_entity_id)
     assert state.state == "12.0"  # 0 EUR + (10-4) kWh * 2 EUR/kWh = 12 EUR
@@ -218,3 +243,55 @@ async def test_cost_sensor_price_entity(
     statistics = await hass.loop.run_in_executor(None, _compile_statistics, hass)
     assert cost_sensor_entity_id in statistics
     assert statistics[cost_sensor_entity_id]["stat"]["sum"] == 31.0
+
+
+async def test_cost_sensor_handle_wh(hass, hass_storage) -> None:
+    """Test energy cost price from sensor entity."""
+    energy_data = data.EnergyManager.default_preferences()
+    energy_data["energy_sources"].append(
+        {
+            "type": "grid",
+            "flow_from": [
+                {
+                    "stat_energy_from": "sensor.energy_consumption",
+                    "entity_energy_from": "sensor.energy_consumption",
+                    "stat_cost": None,
+                    "entity_energy_price": None,
+                    "number_energy_price": 0.5,
+                }
+            ],
+            "flow_to": [],
+            "cost_adjustment_day": 0,
+        }
+    )
+
+    hass_storage[data.STORAGE_KEY] = {
+        "version": 1,
+        "data": energy_data,
+    }
+
+    now = dt_util.utcnow()
+    last_reset = dt_util.utc_from_timestamp(0).isoformat()
+
+    hass.states.async_set(
+        "sensor.energy_consumption",
+        10000,
+        {"last_reset": last_reset, "unit_of_measurement": ENERGY_WATT_HOUR},
+    )
+
+    with patch("homeassistant.util.dt.utcnow", return_value=now):
+        await setup_integration(hass)
+
+    state = hass.states.get("sensor.energy_consumption_cost")
+    assert state.state == "0.0"
+
+    # Energy use bumped to 10 kWh
+    hass.states.async_set(
+        "sensor.energy_consumption",
+        20000,
+        {"last_reset": last_reset, "unit_of_measurement": ENERGY_WATT_HOUR},
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.energy_consumption_cost")
+    assert state.state == "5.0"