diff --git a/.coveragerc b/.coveragerc
index bd9995d1c10..9e269f0a36a 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -1322,10 +1322,8 @@ omit =
     homeassistant/components/upc_connect/*
     homeassistant/components/uscis/sensor.py
     homeassistant/components/vallox/__init__.py
-    homeassistant/components/vallox/const.py
     homeassistant/components/vallox/fan.py
     homeassistant/components/vallox/sensor.py
-    homeassistant/components/vallox/binary_sensor.py
     homeassistant/components/vasttrafik/sensor.py
     homeassistant/components/velbus/__init__.py
     homeassistant/components/velbus/binary_sensor.py
diff --git a/tests/components/vallox/test_sensor.py b/tests/components/vallox/test_sensor.py
index 7649799f56b..dea3f79fbd8 100644
--- a/tests/components/vallox/test_sensor.py
+++ b/tests/components/vallox/test_sensor.py
@@ -158,3 +158,88 @@ async def test_remaining_time_for_filter_in_the_past(
         mocked_filter_end_date,
         _now_at_13(),
     )
+
+
+async def test_cell_state_sensor_heat_recovery(
+    mock_entry: MockConfigEntry, hass: HomeAssistant
+):
+    """Test cell state sensor in heat recovery state."""
+    # Arrange
+    metrics = {"A_CYC_CELL_STATE": 0}
+
+    # Act
+    with patch_metrics(metrics=metrics):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    # Assert
+    sensor = hass.states.get("sensor.vallox_cell_state")
+    assert sensor.state == "Heat Recovery"
+
+
+async def test_cell_state_sensor_cool_recovery(
+    mock_entry: MockConfigEntry, hass: HomeAssistant
+):
+    """Test cell state sensor in cool recovery state."""
+    # Arrange
+    metrics = {"A_CYC_CELL_STATE": 1}
+
+    # Act
+    with patch_metrics(metrics=metrics):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    # Assert
+    sensor = hass.states.get("sensor.vallox_cell_state")
+    assert sensor.state == "Cool Recovery"
+
+
+async def test_cell_state_sensor_bypass(
+    mock_entry: MockConfigEntry, hass: HomeAssistant
+):
+    """Test cell state sensor in bypass state."""
+    # Arrange
+    metrics = {"A_CYC_CELL_STATE": 2}
+
+    # Act
+    with patch_metrics(metrics=metrics):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    # Assert
+    sensor = hass.states.get("sensor.vallox_cell_state")
+    assert sensor.state == "Bypass"
+
+
+async def test_cell_state_sensor_defrosting(
+    mock_entry: MockConfigEntry, hass: HomeAssistant
+):
+    """Test cell state sensor in defrosting state."""
+    # Arrange
+    metrics = {"A_CYC_CELL_STATE": 3}
+
+    # Act
+    with patch_metrics(metrics=metrics):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    # Assert
+    sensor = hass.states.get("sensor.vallox_cell_state")
+    assert sensor.state == "Defrosting"
+
+
+async def test_cell_state_sensor_unknown_state(
+    mock_entry: MockConfigEntry, hass: HomeAssistant
+):
+    """Test cell state sensor in unknown state."""
+    # Arrange
+    metrics = {"A_CYC_CELL_STATE": 4}
+
+    # Act
+    with patch_metrics(metrics=metrics):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    # Assert
+    sensor = hass.states.get("sensor.vallox_cell_state")
+    assert sensor.state == "unknown"