diff --git a/homeassistant/components/duco/sensor.py b/homeassistant/components/duco/sensor.py
index 139842d2db48..df7ea88e622f 100644
--- a/homeassistant/components/duco/sensor.py
+++ b/homeassistant/components/duco/sensor.py
@@ -167,6 +167,7 @@ async def async_setup_entry(
 
     @callback
     def _async_add_new_entities() -> None:
+        """Add new sensor entities and remove stale ones on coordinator updates."""
         # Remove devices whose nodes have disappeared from the API.
         # The firmware removes deregistered RF/wired nodes automatically.
         # BSRH box sensors that are physically unplugged from the PCB are
@@ -190,14 +191,19 @@ async def async_setup_entry(
         for node in coordinator.data.nodes.values():
             if node.node_id in known_nodes:
                 continue
-            known_nodes.add(node.node_id)
             if node.general.node_type == NodeType.UNKNOWN:
-                _LOGGER.warning(
-                    "Duco node %s (%s) has an unsupported device type and will be ignored",
+                # Do not add the node to known_nodes so that it is re-evaluated
+                # on every coordinator update. This allows entities to be
+                # created automatically once a firmware update or library
+                # update adds support for the device type.
+                _LOGGER.debug(
+                    "Duco node %s (%s) has an unsupported device type and will be "
+                    "retried on subsequent coordinator updates",
                     node.node_id,
                     node.general.name,
                 )
                 continue
+            known_nodes.add(node.node_id)
             new_entities.extend(
                 DucoSensorEntity(coordinator, node, description)
                 for description in SENSOR_DESCRIPTIONS
diff --git a/tests/components/duco/test_sensor.py b/tests/components/duco/test_sensor.py
index c39a2ceca1e2..eb0d3b342c56 100644
--- a/tests/components/duco/test_sensor.py
+++ b/tests/components/duco/test_sensor.py
@@ -1,5 +1,6 @@
 """Tests for the Duco sensor platform."""
 
+import logging
 from unittest.mock import AsyncMock, patch
 
 from duco.exceptions import DucoConnectionError, DucoError
@@ -255,3 +256,104 @@ async def test_unknown_node_type_logs_warning_and_creates_no_entities(
         identifiers={(DOMAIN, f"{mock_config_entry.unique_id}_99")}
     )
     assert device is None
+
+
+@pytest.mark.usefixtures("init_integration")
+async def test_previously_unknown_node_gets_entities_after_type_becomes_known(
+    hass: HomeAssistant,
+    mock_config_entry: MockConfigEntry,
+    mock_duco_client: AsyncMock,
+    mock_nodes: list[Node],
+    freezer: FrozenDateTimeFactory,
+) -> None:
+    """Test that a node with UNKNOWN type is retried and gets entities once the type resolves."""
+    node_id = 99
+    ventilation = NodeVentilationInfo(
+        state="AUTO", time_state_remain=0, time_state_end=0, mode="-", flow_lvl_tgt=None
+    )
+    sensor = NodeSensorInfo(co2=None, iaq_co2=None, rh=62.0, iaq_rh=70, temp=21.0)
+
+    def _make_node(node_type: NodeType | str) -> Node:
+        """Create a Node with the given node type for use in tests."""
+        return Node(
+            node_id=node_id,
+            general=NodeGeneralInfo(
+                node_type=node_type,
+                sub_type=0,
+                network_type="RF",
+                parent=1,
+                asso=1,
+                name="Future sensor",
+                identify=0,
+            ),
+            ventilation=ventilation,
+            sensor=sensor,
+        )
+
+    # First poll: UNKNOWN type — no entities created.
+    mock_duco_client.async_get_nodes.return_value = [
+        *mock_nodes,
+        _make_node(NodeType.UNKNOWN),
+    ]
+    freezer.tick(SCAN_INTERVAL)
+    async_fire_time_changed(hass)
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+    assert hass.states.get("sensor.future_sensor_humidity") is None
+
+    # Second poll: type now resolved — entities must be created.
+    mock_duco_client.async_get_nodes.return_value = [*mock_nodes, _make_node("BSRH")]
+    freezer.tick(SCAN_INTERVAL)
+    async_fire_time_changed(hass)
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+    state = hass.states.get("sensor.future_sensor_humidity")
+    assert state is not None
+    assert state.state == "62.0"
+
+
+@pytest.mark.usefixtures("init_integration")
+async def test_unknown_node_logged_at_debug(
+    hass: HomeAssistant,
+    mock_config_entry: MockConfigEntry,
+    mock_duco_client: AsyncMock,
+    mock_nodes: list[Node],
+    freezer: FrozenDateTimeFactory,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that UNKNOWN nodes are logged at DEBUG level on every coordinator update."""
+    unknown_node = Node(
+        node_id=99,
+        general=NodeGeneralInfo(
+            node_type=NodeType.UNKNOWN,
+            sub_type=0,
+            network_type="RF",
+            parent=1,
+            asso=1,
+            name="Future sensor",
+            identify=0,
+        ),
+        ventilation=NodeVentilationInfo(
+            state="AUTO",
+            time_state_remain=0,
+            time_state_end=0,
+            mode="-",
+            flow_lvl_tgt=None,
+        ),
+        sensor=NodeSensorInfo(co2=None, iaq_co2=None, rh=None, iaq_rh=None, temp=None),
+    )
+    mock_duco_client.async_get_nodes.return_value = [*mock_nodes, unknown_node]
+
+    with caplog.at_level(logging.WARNING, logger="homeassistant.components.duco"):
+        freezer.tick(SCAN_INTERVAL)
+        async_fire_time_changed(hass)
+        await hass.async_block_till_done(wait_background_tasks=True)
+
+    assert "has an unsupported device type" not in caplog.text
+
+    with caplog.at_level(logging.DEBUG, logger="homeassistant.components.duco"):
+        freezer.tick(SCAN_INTERVAL)
+        async_fire_time_changed(hass)
+        await hass.async_block_till_done(wait_background_tasks=True)
+
+    assert "has an unsupported device type" in caplog.text