diff --git a/custom_components/myhome/climate.py b/custom_components/myhome/climate.py
index 1735ee0c..d20bfbb0 100644
--- a/custom_components/myhome/climate.py
+++ b/custom_components/myhome/climate.py
@@ -681,11 +681,15 @@ def __init__(
         self._attr_current_humidity: float | None = None
         self._target_temperature: float | None = None
         self._local_offset: float = 0
+        self._local_offset_reported = False
         self._knob_pos: str = "UNKNOWN"
         self._local_target_temperature: float | None = None
         # True while _local_target_temperature is the zone's own dimension 12 report (the
         # setpoint in force, offset included): dimension 14 and 13 frames then leave it alone.
         self._local_target_reported = False
+        self._dim12_at: float | None = None
+        self._dim14_at: float | None = None
+        self._written_target_temperature: tuple[float, float] | None = None
         self._current_temperature_restored = False
         # True while the setpoint / the mode are what Home Assistant saved, not what the zone
         # said since the restart: the silent-zone poll (#466) does not take them for a report.
@@ -1573,12 +1577,60 @@ def _effective_nominal_temperature(self) -> float | None:
             return self._local_target_temperature - self._local_offset
         return None
 
+    def _derive_local_offset(self, local_target: float | None, nominal_target: float | None) -> bool:
+        """Derive the knob offset from a paired Dimension 12 and Dimension 14 when Dimension 13 is absent (#466)."""
+        if (
+            self._local_offset_reported
+            or self._attr_hvac_mode in (None, HVACMode.OFF)
+            or local_target is None
+            or nominal_target is None
+        ):
+            return False
+        diff = round(local_target - nominal_target, 1)
+        if not (-3.0 <= diff <= 3.0 and float(diff).is_integer()):
+            return False
+        offset = int(diff)
+        if offset == 0 and self._local_offset == 0:
+            return False
+        self._local_offset = offset
+        self._knob_pos = "0" if offset == 0 else f"{offset:+d}"
+        return True
+
+    def _reconcile_local_target(self) -> None:
+        """Update nominal setpoint and derived knob offset from a Dimension 12 report (#466)."""
+        now = time.monotonic()
+        written = self._written_target_temperature
+        self._written_target_temperature = None
+        if written is not None and now - written[1] <= _PROTECTION_FRAME_WINDOW:
+            self._derive_local_offset(self._local_target_temperature, written[0])
+            self._dim12_at = None
+            self._dim14_at = None
+        elif self._dim14_at is not None and now - self._dim14_at <= _PROTECTION_FRAME_WINDOW:
+            self._derive_local_offset(self._local_target_temperature, self._target_temperature)
+            self._dim12_at = None
+            self._dim14_at = None
+        self._target_temperature = (
+            self._local_target_temperature - self._local_offset
+            if self._local_target_temperature is not None
+            else None
+        )
+
     def _hydrate_nominal_from_local(self, prev_mode: HVACMode | None) -> None:
         """Promote an initial Dimension 12/14 reading once the zone is known to be active (#819)."""
         if self._central or prev_mode is not None or self._attr_hvac_mode in (None, HVACMode.OFF):
             return
-        if self._target_temperature is None and self._local_target_temperature is not None:
-            self._target_temperature = self._local_target_temperature - self._local_offset
+        if self._local_target_temperature is not None and self._local_target_reported:
+            if (
+                self._written_target_temperature is None
+                and self._target_temperature is not None
+                and self._dim14_at is not None
+                and time.monotonic() - self._dim14_at <= _PROTECTION_FRAME_WINDOW
+            ):
+                self._derive_local_offset(self._local_target_temperature, self._target_temperature)
+                self._dim12_at = None
+                self._dim14_at = None
+            else:
+                self._reconcile_local_target()
         elif (
             self._local_target_temperature is None
             and self._target_temperature is not None
@@ -1808,6 +1860,7 @@ async def async_set_temperature(self, **kwargs: Any) -> None:
         # The write's echo decides what is shown next: dimension 12 where the gateway reports
         # the setpoint in force (F461, MyHomeServer1), else the commanded dimension 14.
         self._local_target_reported = False
+        self._written_target_temperature = (target_temperature, time.monotonic())
 
     def _dimension_3_is_protection(self, message: OWNHeatingEvent) -> bool:
         """Whether a dimension 12/14 frame may be a protection setpoint rather than the nominal one.
@@ -1833,6 +1886,8 @@ def _restore_nominal_before_protection(self) -> None:
         previous nominal back (#383).
         """
         remembered, self._nominal_before_dim12 = self._nominal_before_dim12, None
+        self._dim12_at = None
+        self._dim14_at = None
         if remembered is not None and time.monotonic() - remembered[1] <= _PROTECTION_FRAME_WINDOW:
             self._target_temperature = remembered[0]
 
@@ -1846,6 +1901,8 @@ def _show_nominal(self) -> None:
             return
         self._local_target_temperature = self._target_temperature + self._local_offset
         self._local_target_reported = False
+        self._dim12_at = None
+        self._dim14_at = None
 
     def _apply_zone_state(self, message: OWNHeatingEvent) -> None:
         """Dimension 7: the zone's operating state, and its setpoint in state 'setpoint'.
@@ -2042,6 +2099,8 @@ def handle_event(self, message: OWNHeatingEvent) -> None:
             )
             self._attr_native_current_temperature = message.main_temperature
             self._current_temperature_restored = False
+            self._dim12_at = None
+            self._dim14_at = None
         elif message.message_type == MESSAGE_TYPE_MAIN_HUMIDITY:
             LOGGER.debug(
                 "%s %s",
@@ -2059,7 +2118,23 @@ def handle_event(self, message: OWNHeatingEvent) -> None:
             )
             self._target_temperature = message.set_temperature
             self._target_temperature_restored = False
+            self._written_target_temperature = None
+            now = time.monotonic()
             is_protection_or_off = self._dimension_3_is_protection(message)
+            if (
+                not is_protection_or_off
+                and self._dim12_at is not None
+                and now - self._dim12_at <= _PROTECTION_FRAME_WINDOW
+            ):
+                self._derive_local_offset(self._local_target_temperature, self._target_temperature)
+                self._dim12_at = None
+                self._dim14_at = None
+            else:
+                self._dim14_at = (
+                    now
+                    if self._target_temperature is not None and self._attr_hvac_mode != HVACMode.OFF
+                    else None
+                )
             # Dimension 14 is the commanded setpoint. The thermostat can regulate to another one
             # (F461: 14 = 21.0 while 12 = 23.5), so a dimension 12 report stays what is shown.
             if not is_protection_or_off and not self._local_target_reported:
@@ -2075,6 +2150,9 @@ def handle_event(self, message: OWNHeatingEvent) -> None:
                 message.human_readable_log,
             )
             self._local_offset = message.local_offset if message.local_offset is not None else 0
+            self._local_offset_reported = True
+            self._dim12_at = None
+            self._dim14_at = None
             if message.local_control_state in (LOCAL_CONTROL_UNKNOWN, None):
                 self._knob_pos = "UNKNOWN"
             elif message.local_control_state == LOCAL_CONTROL_OFFSET:
@@ -2103,15 +2181,16 @@ def handle_event(self, message: OWNHeatingEvent) -> None:
             )
             self._local_target_temperature = message.local_set_temperature
             self._local_target_reported = self._local_target_temperature is not None
+            self._dim12_at = (
+                time.monotonic()
+                if self._local_target_reported and self._attr_hvac_mode != HVACMode.OFF
+                else None
+            )
             self._target_temperature_restored = False
             is_protection_or_off = self._dimension_3_is_protection(message)
             if not is_protection_or_off:
                 self._remember_nominal()
-                self._target_temperature = (
-                    self._local_target_temperature - self._local_offset
-                    if self._local_target_temperature is not None
-                    else None
-                )
+                self._reconcile_local_target()
         elif message.message_type == MESSAGE_TYPE_SEASON:
             # *4*1*Z## / *4*0*Z## is the zone operation mode frame: the zone
             # (or the central unit) runs in the heating / conditioning season
diff --git a/tests/test_climate_setpoint_in_force.py b/tests/test_climate_setpoint_in_force.py
index 0193741b..e2f9fc6d 100644
--- a/tests/test_climate_setpoint_in_force.py
+++ b/tests/test_climate_setpoint_in_force.py
@@ -26,7 +26,7 @@
 )
 
 
-def _zone(hass, where="2", gateway=None, **kwargs):
+def _zone(hass, where="2", gateway=None, standalone=True, **kwargs):
     if gateway is None:
         gateway = MagicMock()
         gateway.mac = "00:03:50:00:04:97"
@@ -35,7 +35,7 @@ def _zone(hass, where="2", gateway=None, **kwargs):
         gateway.has_central_unit = False
     zone = MyHOMEClimate(
         hass=hass, name=f"Zone {where}", device_id=f"4-{where}", who="4", where=where,
-        heating=True, cooling=True, fan=False, standalone=True, central=False,
+        heating=True, cooling=True, fan=False, standalone=standalone, central=False,
         manufacturer="BTicino", model="Heating Zone", gateway=gateway, **kwargs,
     )
     zone.hass = hass
@@ -65,6 +65,7 @@ async def test_dimension_14_before_dimension_12_shows_the_setpoint_in_force(hass
     zone = _zone(hass)
     _feed(zone, "*#4*2*0*0239##", "*#4*2*14*0210*3##", "*#4*2*12*0235*3##", "*4*1*2##", "*#4*2*13*00##")
     assert zone.target_temperature == 23.5
+    assert zone._target_temperature == 21.0
 
 
 @pytest.mark.parametrize(
@@ -249,3 +250,285 @@ async def test_unreadable_restored_setpoint_is_ignored(hass):
     await restored.async_restore_last_state(State("climate.zone_2", "heat", {"temperature": "warm", "local_offset": 2}))
     assert restored.target_temperature is None
     assert restored._local_offset == 0
+
+
+# ------------------------------------------------------------------ H/L4684 derived local offset without dimension 13 (#466)
+
+async def test_hl4684_zone_88_setpoint_sequence_derives_offset_and_compensates_writes(hass):
+    """Replay H/L4684 (FW 6.0.11) + 3550 Zone 88 frames from #466 (09-11-53.json).
+
+    On H/L4684, ``*#4*Z##`` is NACKed, the 3550's quarter-hour sweep only surfaces
+    Dimension 0, Dimension 14, and Dimension 20 on the event session, and Dimension 13
+    (``*#4*Z*13*OO##``) is never emitted. On each ``*#4*#88*#14*TTTT*3##`` write, the bus
+    emits Dimension 0, Dimension 12 (effective setpoint = nominal + knob offset),
+    ``*4*1*88##``, optionally Dimension 14 (present on frames 97-102, 118-123, 126-131;
+    omitted on frames 104-108, 113-117, 132-136), and ``*4*110*#88##``.
+    """
+    zone = _zone(hass, where="88", standalone=False)
+    zone._gateway_handler.has_central_unit = True
+
+    # 1. Quarter-hour 3550 sweep on H/L4684 (09-11-53.json frames 36-37, 45): Dimension 0, 14, 20
+    _feed(zone, "*#4*88*0*0210##", "*#4*88*14*0170*3##", "*#4*88#1*20*5##")
+    assert zone._target_temperature == 17.0
+    assert zone._local_offset == 0
+    assert zone.extra_state_attributes["knob_pos"] == "UNKNOWN"
+
+    # 2. First write (09-11-53.json frames 97-102): includes Dimension 12 (0075) and Dimension 14 (0105)
+    await zone.async_set_temperature(temperature=10.5)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#88*#14*0105*3##"
+    _feed(
+        zone,
+        "*#4*88*0*0210##",
+        "*#4*88*12*0075*3##",
+        "*4*1*88##",
+        "*#4*88*14*0105*3##",
+        "*4*110*#88##",
+    )
+    assert zone.hvac_mode == HVACMode.HEAT
+    assert zone.target_temperature == 7.5
+    assert zone._target_temperature == 10.5
+    assert zone.extra_state_attributes["local_offset"] == -3
+    assert zone.extra_state_attributes["knob_pos"] == "-3"
+
+    # 3. Second write (09-11-53.json frames 104-108, Dimension 14 omitted):
+    #    user sets 24.0 °C -> compensated with -3 offset writes 27.0 °C (0270)
+    zone._gateway_handler.send.reset_mock()
+    await zone.async_set_temperature(temperature=24.0)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#88*#14*0270*3##"
+    _feed(
+        zone,
+        "*#4*88*0*0210##",
+        "*#4*88*12*0240*3##",
+        "*4*1*88##",
+        "*4*110*#88##",
+    )
+    assert zone.target_temperature == 24.0
+    assert zone._target_temperature == 27.0
+    assert zone.extra_state_attributes["local_offset"] == -3
+    assert zone.extra_state_attributes["knob_pos"] == "-3"
+
+    # 4. Third write (09-11-53.json frames 113-117, Dimension 14 omitted):
+    #    user sets 23.0 °C -> writes 26.0 °C (0260)
+    zone._gateway_handler.send.reset_mock()
+    await zone.async_set_temperature(temperature=23.0)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#88*#14*0260*3##"
+    _feed(
+        zone,
+        "*#4*88*0*0210##",
+        "*#4*88*12*0230*3##",
+        "*4*1*88##",
+        "*4*110*#88##",
+    )
+    assert zone.target_temperature == 23.0
+    assert zone._target_temperature == 26.0
+    assert zone.extra_state_attributes["local_offset"] == -3
+
+    # 5. Fifth write (09-11-53.json frames 126-131, Dimension 14 included):
+    #    user sets 23.5 °C -> writes 26.5 °C (0265)
+    zone._gateway_handler.send.reset_mock()
+    await zone.async_set_temperature(temperature=23.5)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#88*#14*0265*3##"
+    _feed(
+        zone,
+        "*#4*88*0*0210##",
+        "*#4*88*12*0235*3##",
+        "*4*1*88##",
+        "*#4*88*14*0265*3##",
+        "*4*110*#88##",
+    )
+    assert zone.target_temperature == 23.5
+    assert zone._target_temperature == 26.5
+    assert zone.extra_state_attributes["local_offset"] == -3
+
+    # 6. Sixth write (09-11-53.json frames 132-136, Dimension 14 omitted):
+    #    user sets 27.0 °C -> writes 30.0 °C (0300)
+    zone._gateway_handler.send.reset_mock()
+    await zone.async_set_temperature(temperature=27.0)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#88*#14*0300*3##"
+    _feed(
+        zone,
+        "*#4*88*0*0210##",
+        "*#4*88*12*0270*3##",
+        "*4*1*88##",
+        "*4*110*#88##",
+    )
+    assert zone.target_temperature == 27.0
+    assert zone._target_temperature == 30.0
+    assert zone.extra_state_attributes["local_offset"] == -3
+
+
+async def test_hl4684_write_omitting_dimension_14_derives_offset_from_written_nominal(hass):
+    """When H/L4684 omits Dimension 14 on the first write (09-13-19.json frames 136-141), the written nominal derives the offset."""
+    zone = _zone(hass, where="55", standalone=False)
+    zone._gateway_handler.has_central_unit = True
+
+    await zone.async_set_temperature(temperature=24.0)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == "*#4*#55*#14*0240*3##"
+    _feed(
+        zone,
+        "*#4*55*0*0221##",
+        "*#4*55*12*0210*3##",
+        "*4*1*55##",
+        "*#4*55#1*20*5##",
+        "*4*110*#55##",
+    )
+    assert zone.hvac_mode == HVACMode.HEAT
+    assert zone.target_temperature == 21.0
+    assert zone._target_temperature == 24.0
+    assert zone.extra_state_attributes["local_offset"] == -3
+    assert zone.extra_state_attributes["knob_pos"] == "-3"
+
+
+@pytest.mark.parametrize(
+    ("where", "burst", "expected_local", "expected_nominal", "expected_offset", "expected_knob", "next_set", "expected_tx"),
+    [
+        (
+            "33",
+            ("*#4*33*0*0218##", "*#4*33*12*0260*3##", "*4*1*33##", "*#4*33*14*0270*3##", "*4*110*#33##"),
+            26.0,
+            27.0,
+            -1,
+            "-1",
+            24.0,
+            "*#4*#33*#14*0250*3##",
+        ),
+        (
+            "22",
+            ("*#4*22*0*0223##", "*#4*22*12*0240*3##", "*4*1*22##", "*#4*22*14*0260*3##", "*4*110*#22##"),
+            24.0,
+            26.0,
+            -2,
+            "-2",
+            22.0,
+            "*#4*#22*#14*0240*3##",
+        ),
+        (
+            "44",
+            ("*#4*44*0*0238##", "*#4*44*12*0210*3##", "*4*1*44##", "*#4*44*14*0240*3##", "*4*110*#44##"),
+            21.0,
+            24.0,
+            -3,
+            "-3",
+            21.0,
+            "*#4*#44*#14*0240*3##",
+        ),
+        (
+            "55",
+            ("*#4*55*0*0221##", "*#4*55*12*0200*3##", "*4*1*55##", "*#4*55*14*0230*3##", "*4*110*#55##"),
+            20.0,
+            23.0,
+            -3,
+            "-3",
+            24.0,
+            "*#4*#55*#14*0270*3##",
+        ),
+    ],
+    ids=["zone-33-offset-minus-1", "zone-22-offset-minus-2", "zone-44-offset-minus-3", "zone-55-offset-minus-3"],
+)
+async def test_hl4684_captured_zone_bursts_derive_knob_offsets(
+    hass, where, burst, expected_local, expected_nominal, expected_offset, expected_knob, next_set, expected_tx
+):
+    """Captured H/L4684 bursts for zones 33, 22, 44, and 55 (09-13-19.json) derive each zone's integer knob offset."""
+    zone = _zone(hass, where=where, standalone=False)
+    zone._gateway_handler.has_central_unit = True
+    _feed(zone, *burst)
+    assert zone.target_temperature == expected_local
+    assert zone._target_temperature == expected_nominal
+    assert zone.extra_state_attributes["local_offset"] == expected_offset
+    assert zone.extra_state_attributes["knob_pos"] == expected_knob
+
+    await zone.async_set_temperature(temperature=next_set)
+    assert str(zone._gateway_handler.send.await_args.args[0]) == expected_tx
+
+
+@pytest.mark.parametrize(
+    ("frames", "expected_offset", "expected_knob", "expected_target", "expected_nominal"),
+    [
+        (
+            ("*4*1*2##", "*#4*2*14*0240*3##", "*#4*2*12*0210*3##"),
+            -3,
+            "-3",
+            21.0,
+            24.0,
+        ),
+        (
+            ("*#4*2*14*0240*3##", "*4*1*2##", "*#4*2*12*0210*3##"),
+            -3,
+            "-3",
+            21.0,
+            24.0,
+        ),
+        (
+            ("*4*1*2##", "*#4*2*12*0230*3##", "*#4*2*14*0210*3##"),
+            2,
+            "+2",
+            23.0,
+            21.0,
+        ),
+        (
+            ("*4*1*2##", "*#4*2*14*0210*3##", "*#4*2*12*0210*3##"),
+            0,
+            "UNKNOWN",
+            21.0,
+            21.0,
+        ),
+    ],
+    ids=[
+        "dim14-then-dim12-negative",
+        "dim14-before-mode-then-dim12-negative",
+        "dim12-then-dim14-positive",
+        "dim14-then-dim12-zero-leaves-knob-unknown",
+    ],
+)
+async def test_derived_offset_handles_both_frame_orders_and_signs(
+    hass, frames, expected_offset, expected_knob, expected_target, expected_nominal
+):
+    """Paired Dimension 12 and 14 frames derive -3..+3 integer offsets in either arrival order."""
+    zone = _zone(hass)
+    _feed(zone, *frames)
+    assert zone.target_temperature == expected_target
+    assert zone._target_temperature == expected_nominal
+    assert zone.extra_state_attributes["local_offset"] == expected_offset
+    assert zone.extra_state_attributes["knob_pos"] == expected_knob
+
+
+async def test_derived_nonzero_offset_resets_to_zero_when_knob_returned_to_center(hass):
+    """Once a nonzero knob offset was derived, a later 12 == 14 pair resets local_offset to 0 and knob_pos to '0'."""
+    zone = _zone(hass)
+    _feed(zone, "*4*1*2##", "*#4*2*12*0210*3##", "*#4*2*14*0240*3##")
+    assert zone.extra_state_attributes["local_offset"] == -3
+    assert zone.extra_state_attributes["knob_pos"] == "-3"
+
+    _feed(zone, "*#4*2*0*0215##", "*#4*2*12*0240*3##", "*#4*2*14*0240*3##")
+    assert zone.extra_state_attributes["local_offset"] == 0
+    assert zone.extra_state_attributes["knob_pos"] == "0"
+    assert zone.target_temperature == 24.0
+    assert zone._target_temperature == 24.0
+
+
+async def test_explicit_dimension_13_prevents_derived_offset_override(hass):
+    """Once Dimension 13 is reported, a later integer difference between 12 and 14 does not override it."""
+    zone = _zone(hass)
+    _feed(zone, "*4*1*2##", "*#4*2*13*00##", "*#4*2*12*0230*3##", "*#4*2*14*0210*3##")
+    assert zone.extra_state_attributes["local_offset"] == 0
+    assert zone.extra_state_attributes["knob_pos"] == "0"
+    assert zone.target_temperature == 23.0
+
+
+async def test_out_of_range_or_stale_dimension_pairs_do_not_derive_offset(hass, monkeypatch):
+    """Differences outside -3..+3 °C or separated beyond the burst window do not derive a knob offset."""
+    clock = [1000.0]
+    monkeypatch.setattr(climate_module.time, "monotonic", lambda: clock[0])
+    zone = _zone(hass)
+    # 1. Difference of -14 °C (e.g. protection 7.0 vs comfort 21.0) is outside -3..+3
+    _feed(zone, "*4*1*2##", "*#4*2*12*0070*3##", "*#4*2*14*0210*3##")
+    assert zone.extra_state_attributes["local_offset"] == 0
+    assert zone.extra_state_attributes["knob_pos"] == "UNKNOWN"
+
+    # 2. Separated beyond _PROTECTION_FRAME_WINDOW (2.0s)
+    _feed(zone, "*#4*2*12*0200*3##")
+    clock[0] += 5.0
+    _feed(zone, "*#4*2*14*0220*3##")
+    assert zone.extra_state_attributes["local_offset"] == 0
+    assert zone.extra_state_attributes["knob_pos"] == "UNKNOWN"
+