diff --git a/docs/getting-started.md b/docs/getting-started.md
index 40f0e371..0db3ba4e 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -63,6 +63,29 @@ async def main() -> None:
 asyncio.run(main())
 ```
 
+## Cooling setpoint support
+
+Some BSB/LPB controllers expose a cooling comfort setpoint for heating circuit
+1. The client maps BSB-LAN parameter `902` to `target_temperature_high`; the
+duplicate decimal parameters `902.1` and `902.2` are not used.
+
+Cooling support is optional. During section validation, unsupported parameters
+are removed from the active API map, so integrations can detect support by
+checking whether `state.target_temperature_high` is present.
+
+```python
+async with BSBLAN(config) as client:
+    state = await client.state(include=["target_temperature_high"])
+
+    if state.target_temperature_high is not None:
+        print(f"Cooling setpoint: {state.target_temperature_high.value}")
+        await client.thermostat(target_temperature_high="24.0")
+```
+
+BSB-LAN writes one parameter at a time. If an application exposes a heat/cool
+temperature range, write `target_temperature` and `target_temperature_high` with
+separate `thermostat()` calls.
+
 ## PPS bus support
 
 PPS bus devices are detected from the device metadata returned by BSB-LAN. The
diff --git a/docs/index.md b/docs/index.md
index c6eb3f34..824f7638 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -7,6 +7,7 @@ Asynchronous Python client for [BSB-LAN](https://github.com/fredlcore/bsb_lan) d
 - Async/await support using `aiohttp`
 - Read heating state, sensor data, and device information
 - Control thermostat settings and hot water parameters
+- Detect optional cooling setpoints for heat/cool range controls
 - Fully typed with PEP 561 support
 - Automatic API version detection (v1/v3)
 - Lazy loading with per-section validation
diff --git a/src/bsblan/bsblan.py b/src/bsblan/bsblan.py
index 857e8bdf..fba26e55 100644
--- a/src/bsblan/bsblan.py
+++ b/src/bsblan/bsblan.py
@@ -1137,6 +1137,7 @@ async def thermostat(
         target_temperature: str | None = None,
         hvac_mode: int | None = None,
         circuit: int = 1,
+        target_temperature_high: str | float | None = None,
     ) -> None:
         """Change the state of the thermostat through BSB-Lan.
 
@@ -1147,11 +1148,15 @@ async def thermostat(
                 For PPS, valid values are 0=off, 1=auto, and 3=heat/manual;
                 they are translated to PPS raw values before posting.
             circuit: The heating circuit number (1 or 2). Defaults to 1.
+            target_temperature_high: The cooling comfort setpoint to set.
 
         Example:
             # Set HC1 temperature
             await client.thermostat(target_temperature="21.0")
 
+            # Set HC1 cooling comfort setpoint
+            await client.thermostat(target_temperature_high="24.0")
+
             # Set HC2 mode
             await client.thermostat(hvac_mode=1, circuit=2)
 
@@ -1164,6 +1169,7 @@ async def thermostat(
         self._validate_single_parameter(
             target_temperature,
             hvac_mode,
+            target_temperature_high,
             error_msg=ErrorMsg.MULTI_PARAMETER,
         )
 
@@ -1171,6 +1177,7 @@ async def thermostat(
             target_temperature,
             hvac_mode,
             circuit,
+            target_temperature_high,
         )
         await self._set_device_state(state)
 
@@ -1179,6 +1186,7 @@ async def _prepare_thermostat_state(
         target_temperature: str | None,
         hvac_mode: int | None,
         circuit: int = 1,
+        target_temperature_high: str | float | None = None,
     ) -> dict[str, Any]:
         """Prepare the thermostat state for setting.
 
@@ -1186,6 +1194,7 @@ async def _prepare_thermostat_state(
             target_temperature (str | None): The target temperature to set.
             hvac_mode (int | None): The HVAC mode to set as raw integer.
             circuit: The heating circuit number (1 or 2).
+            target_temperature_high: The cooling comfort setpoint to set.
 
         Returns:
             dict[str, Any]: The prepared state for the thermostat.
@@ -1205,6 +1214,19 @@ async def _prepare_thermostat_state(
                     "Type": "1",
                 },
             )
+        if target_temperature_high is not None:
+            self._validate_target_temperature_high(target_temperature_high)
+            param_id = param_ids.get("target_temperature_high")
+            if param_id is None:
+                parameter_name = "target_temperature_high"
+                raise BSBLANInvalidParameterError(parameter_name)
+            state.update(
+                {
+                    "Parameter": param_id,
+                    "Value": str(target_temperature_high),
+                    "Type": "1",
+                },
+            )
         if hvac_mode is not None:
             self._validate_hvac_mode(hvac_mode)
             hvac_value = str(hvac_mode)
@@ -1225,6 +1247,16 @@ def _thermostat_params(self, circuit: int) -> dict[str, str]:
             return {"target_temperature": "15004", "hvac_mode": "15000"}
         return CircuitConfig.THERMOSTAT_PARAMS[circuit]
 
+    def _validate_target_temperature_high(
+        self,
+        target_temperature_high: str | float,
+    ) -> None:
+        """Validate the cooling target temperature value."""
+        try:
+            float(target_temperature_high)
+        except ValueError as err:
+            raise BSBLANInvalidParameterError(str(target_temperature_high)) from err
+
     async def _validate_target_temperature(
         self,
         target_temperature: str,
diff --git a/src/bsblan/constants.py b/src/bsblan/constants.py
index c2d0cd18..6663570f 100644
--- a/src/bsblan/constants.py
+++ b/src/bsblan/constants.py
@@ -29,6 +29,7 @@ class APIConfig(TypedDict):
     "700": "hvac_mode",
     "710": "target_temperature",
     "900": "hvac_mode_changeover",
+    "902": "target_temperature_high",
     # -------
     "8000": "hvac_action",
     "8740": "current_temperature",
@@ -154,7 +155,11 @@ class CircuitConfig:
         2: "staticValues_circuit2",
     }
     THERMOSTAT_PARAMS: Final[dict[int, dict[str, str]]] = {
-        1: {"target_temperature": "710", "hvac_mode": "700"},
+        1: {
+            "target_temperature": "710",
+            "target_temperature_high": "902",
+            "hvac_mode": "700",
+        },
         2: {"target_temperature": "1010", "hvac_mode": "1000"},
     }
     PROBE_PARAMS: Final[dict[int, str]] = {
diff --git a/src/bsblan/models.py b/src/bsblan/models.py
index 5d4216b7..3ddb5d6c 100644
--- a/src/bsblan/models.py
+++ b/src/bsblan/models.py
@@ -469,6 +469,7 @@ class State(BaseModel):
 
     hvac_mode: EntityInfo[int] | None = None
     target_temperature: EntityInfo[float] | None = None
+    target_temperature_high: EntityInfo[float] | None = None
     hvac_action: EntityInfo[int] | None = None
     hvac_mode_changeover: EntityInfo[int] | None = None
     current_temperature: EntityInfo[float] | None = None
diff --git a/tests/fixtures/state.json b/tests/fixtures/state.json
index 3bad093f..4b946672 100644
--- a/tests/fixtures/state.json
+++ b/tests/fixtures/state.json
@@ -36,6 +36,19 @@
     "readwrite": 0,
     "unit": ""
   },
+  "902": {
+    "name": "Cooling circuit 1 - Comfort setpoint",
+    "dataType_name": "TEMP",
+    "dataType_family": "VALS",
+    "error": 0,
+    "value": "21.0",
+    "desc": "",
+    "precision": 0.1,
+    "dataType": 0,
+    "readonly": 0,
+    "readwrite": 0,
+    "unit": "°C"
+  },
   "8000": {
     "name": "Status heating circuit 1",
     "dataType_name": "ENUM",
diff --git a/tests/test_circuit.py b/tests/test_circuit.py
index c0c1dd9b..eba03533 100644
--- a/tests/test_circuit.py
+++ b/tests/test_circuit.py
@@ -397,6 +397,24 @@ async def test_thermostat_circuit2_no_params(
     assert str(exc_info.value) == ErrorMsg.MULTI_PARAMETER
 
 
+@pytest.mark.asyncio
+async def test_thermostat_circuit2_rejects_cooling_temperature(
+    mock_bsblan_circuit: BSBLAN,
+) -> None:
+    """Test cooling target writes are only mapped for circuit 1."""
+    mock_bsblan_circuit._circuit_temp_ranges[2] = {
+        "min": 8.0,
+        "max": 28.0,
+    }
+    mock_bsblan_circuit._circuit_temp_initialized.add(2)
+
+    with pytest.raises(BSBLANInvalidParameterError):
+        await mock_bsblan_circuit.thermostat(
+            target_temperature_high="24",
+            circuit=2,
+        )
+
+
 # --- Temperature range initialization tests ---
 
 
diff --git a/tests/test_constants.py b/tests/test_constants.py
index 337b0ec0..d8b21ca6 100644
--- a/tests/test_constants.py
+++ b/tests/test_constants.py
@@ -21,17 +21,17 @@
     [
         (
             "v1",
-            {"700", "710", "714", "730"},  # hvac_mode, target_temp, min_temp, v1_max
+            {"700", "710", "902", "714", "730"},
             {"770", "716"},  # v3_boost, v3_max_temp
         ),
         (
             "v3",
-            {"700", "710", "714", "770", "716"},  # base + v3 extensions
+            {"700", "710", "902", "714", "770", "716"},
             {"730"},  # v1_max_temp
         ),
         (
             "v5",  # Unknown version
-            {"700", "710", "714"},  # only base parameters
+            {"700", "710", "902", "714"},  # only base parameters
             {"770", "730", "716"},  # no extensions
         ),
     ],
@@ -138,6 +138,15 @@ def test_hot_water_parameter_groups_total_count() -> None:
     assert total_grouped == len(BASE_HOT_WATER_PARAMS)
 
 
+def test_cooling_target_uses_single_base_parameter() -> None:
+    """Test cooling setpoint uses 902, not duplicate decimal parameters."""
+    config = build_api_config("v3")
+
+    assert config["heating"]["902"] == "target_temperature_high"
+    assert "902.1" not in config["heating"]
+    assert "902.2" not in config["heating"]
+
+
 @pytest.mark.parametrize("version", ["v1", "v3"])
 def test_api_config_structure(version: str) -> None:
     """Test that API config has required structure."""
diff --git a/tests/test_state.py b/tests/test_state.py
index 83cc8d4f..40082b01 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -59,6 +59,12 @@ async def test_state(monkeypatch: Any) -> None:
         assert state.target_temperature.desc == ""
         assert state.target_temperature.unit == "°C"
 
+        # Cooling target temperature assertions
+        assert state.target_temperature_high is not None
+        assert state.target_temperature_high.value == 21.0
+        assert state.target_temperature_high.desc == ""
+        assert state.target_temperature_high.unit == "°C"
+
     # HVAC mode changeover assertions
     assert state.hvac_mode_changeover is not None
     assert state.hvac_mode_changeover.value == 2
@@ -81,5 +87,68 @@ async def test_state(monkeypatch: Any) -> None:
 
     # Verify API call
     request_mock.assert_called_once_with(
-        params={"Parameter": "700,710,900,8000,8740,770"}
+        params={"Parameter": "700,710,900,902,8000,8740,770"}
     )
+
+
+@pytest.mark.asyncio
+async def test_state_with_cooling_include(monkeypatch: Any) -> None:
+    """Test fetching only the cooling target temperature."""
+    async with aiohttp.ClientSession() as session:
+        config = BSBLANConfig(host="example.com")
+        bsblan = BSBLAN(config, session=session)
+
+        monkeypatch.setattr(bsblan, "_firmware_version", "1.0.38-20200730234859")
+        monkeypatch.setattr(bsblan, "_api_version", "v3")
+        monkeypatch.setattr(bsblan, "_api_data", API_V3)
+
+        api_validator = APIValidator(API_V3)
+        api_validator.validated_sections.add("heating")
+        bsblan._api_validator = api_validator
+
+        state_data = json.loads(load_fixture("state.json"))
+        request_mock: AsyncMock = AsyncMock(return_value={"902": state_data["902"]})
+        monkeypatch.setattr(bsblan, "_request", request_mock)
+
+        state: State = await bsblan.state(include=["target_temperature_high"])
+
+        assert state.target_temperature_high is not None
+        assert state.target_temperature_high.value == 21.0
+        assert state.target_temperature is None
+        request_mock.assert_awaited_once_with(params={"Parameter": "902"})
+
+
+@pytest.mark.asyncio
+async def test_state_without_cooling_strips_target_temperature_high(
+    monkeypatch: Any,
+) -> None:
+    """Test unsupported cooling setpoint is stripped during validation."""
+    async with aiohttp.ClientSession() as session:
+        config = BSBLANConfig(host="example.com")
+        bsblan = BSBLAN(config, session=session)
+
+        monkeypatch.setattr(bsblan, "_firmware_version", "1.0.38-20200730234859")
+        monkeypatch.setattr(bsblan, "_api_version", "v3")
+        bsblan._api_data = {
+            section: params.copy() for section, params in API_V3.items()
+        }
+        bsblan._api_validator = APIValidator(bsblan._api_data)
+
+        state_data = json.loads(load_fixture("state.json"))
+        validation_response = {"700": state_data["700"]}
+        fetch_response = {"700": state_data["700"]}
+        request_mock: AsyncMock = AsyncMock(
+            side_effect=[validation_response, fetch_response]
+        )
+        monkeypatch.setattr(bsblan, "_request", request_mock)
+
+        state: State = await bsblan.state(
+            include=["hvac_mode", "target_temperature_high"]
+        )
+
+        assert state.hvac_mode is not None
+        assert state.target_temperature_high is None
+        assert bsblan.get_parameter_id("target_temperature_high") is None
+        assert [
+            call.kwargs["params"]["Parameter"] for call in request_mock.await_args_list
+        ] == ["700,902", "700"]
diff --git a/tests/test_thermostat.py b/tests/test_thermostat.py
index 246600f8..4c40f0c4 100644
--- a/tests/test_thermostat.py
+++ b/tests/test_thermostat.py
@@ -117,6 +117,26 @@ async def test_change_temperature(
     await mock_bsblan.thermostat(target_temperature="20")
 
 
+@pytest.mark.asyncio
+async def test_change_cooling_temperature(
+    mock_bsblan: BSBLAN,
+    mock_aresponses: ResponsesMockServer,
+) -> None:
+    """Test changing BSBLAN cooling setpoint."""
+    expected_data = {
+        "Parameter": "902",
+        "Value": "32.0",
+        "Type": "1",
+    }
+    mock_aresponses.add(
+        "example.com",
+        "/JS",
+        "POST",
+        create_response_handler(expected_data),
+    )
+    await mock_bsblan.thermostat(target_temperature_high=32.0)
+
+
 @pytest.mark.asyncio
 async def test_change_hvac_mode(
     mock_bsblan: BSBLAN,
@@ -144,6 +164,13 @@ async def test_invalid_temperature(mock_bsblan: BSBLAN) -> None:
         await mock_bsblan.thermostat(target_temperature="35")
 
 
+@pytest.mark.asyncio
+async def test_invalid_cooling_temperature(mock_bsblan: BSBLAN) -> None:
+    """Test setting an invalid cooling temperature."""
+    with pytest.raises(BSBLANInvalidParameterError):
+        await mock_bsblan.thermostat(target_temperature_high="invalid")
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "invalid_mode",
@@ -191,3 +218,16 @@ async def test_no_parameters(mock_bsblan: BSBLAN) -> None:
     with pytest.raises(BSBLANError) as exc_info:
         await mock_bsblan.thermostat()
     assert str(exc_info.value) == ErrorMsg.MULTI_PARAMETER
+
+
+@pytest.mark.asyncio
+async def test_cooling_temperature_with_other_parameter_raises(
+    mock_bsblan: BSBLAN,
+) -> None:
+    """Test cooling setpoint respects one-parameter-per-call rule."""
+    with pytest.raises(BSBLANError) as exc_info:
+        await mock_bsblan.thermostat(
+            target_temperature="20",
+            target_temperature_high="24",
+        )
+    assert str(exc_info.value) == ErrorMsg.MULTI_PARAMETER