diff --git a/homeassistant/components/aranet/sensor.py b/homeassistant/components/aranet/sensor.py
index 22db0402eda..28f4593beca 100644
--- a/homeassistant/components/aranet/sensor.py
+++ b/homeassistant/components/aranet/sensor.py
@@ -79,7 +79,7 @@ SENSOR_DESCRIPTIONS = {
         translation_key="concentration_level",
         name="Concentration Level",
         device_class=SensorDeviceClass.ENUM,
-        options=[status.name for status in Color],
+        options=[status.name.lower() for status in Color],
     ),
     "co2": AranetSensorEntityDescription(
         key="co2",
@@ -169,7 +169,7 @@ def sensor_update_to_bluetooth_data_update(
         if val == -1:
             continue
         if key == "status":
-            val = val.name
+            val = val.name.lower()
         val = val * desc.scale
         data[tag] = val
         names[tag] = desc.name
diff --git a/tests/components/aranet/test_sensor.py b/tests/components/aranet/test_sensor.py
index f8e9d645f3e..8de97d7b934 100644
--- a/tests/components/aranet/test_sensor.py
+++ b/tests/components/aranet/test_sensor.py
@@ -216,11 +216,11 @@ async def test_sensors_aranet4(
 
     status_sensor = hass.states.get("sensor.aranet4_12345_concentration_level")
     status_sensor_attrs = status_sensor.attributes
-    assert status_sensor.state == "GREEN"
+    assert status_sensor.state == "green"
     assert (
         status_sensor_attrs[ATTR_FRIENDLY_NAME] == "Aranet4 12345 Concentration Level"
     )
-    assert status_sensor_attrs[ATTR_OPTIONS] == ["ERROR", "GREEN", "YELLOW", "RED"]
+    assert status_sensor_attrs[ATTR_OPTIONS] == ["error", "green", "yellow", "red"]
 
     # Check device context for the battery sensor
     entity = entity_registry.async_get("sensor.aranet4_12345_battery")
@@ -301,11 +301,11 @@ async def test_sensors_aranetrn(
 
     status_sensor = hass.states.get("sensor.aranetrn_12345_concentration_level")
     status_sensor_attrs = status_sensor.attributes
-    assert status_sensor.state == "GREEN"
+    assert status_sensor.state == "green"
     assert (
         status_sensor_attrs[ATTR_FRIENDLY_NAME] == "AranetRn+ 12345 Concentration Level"
     )
-    assert status_sensor_attrs[ATTR_OPTIONS] == ["ERROR", "GREEN", "YELLOW", "RED"]
+    assert status_sensor_attrs[ATTR_OPTIONS] == ["error", "green", "yellow", "red"]
 
     # Check device context for the battery sensor
     entity = entity_registry.async_get("sensor.aranetrn_12345_battery")