diff --git a/docs/baseline-downgrade-followups.md b/docs/baseline-downgrade-followups.md
index 0b7464c1..cc3931d3 100644
--- a/docs/baseline-downgrade-followups.md
+++ b/docs/baseline-downgrade-followups.md
@@ -68,5 +68,32 @@ issue before trusting the cohort.
 ## 4. Predicted-property display path (e.g. property 721167)
 
 721167 has **no lodged EPC** (predicted). Its Heating-Control / Main-Fuel /
-Ventilation Unknowns come from the prediction + landlord-override **overlay** not
-populating the display fields — a separate path from the lodged-cert mappers.
+Ventilation Unknowns come from the prediction synthesis path
+(`domain/epc_prediction/epc_prediction.py`), **not** the lodged-cert mappers and
+**not** the landlord-override overlay (`overlays_from` is simulation-time only,
+ADR-0032 — it never writes the persisted/displayed EPC). Investigated and fixed
+on `fix/predicted-property-display-unknowns`:
+
+- **Heating Control — FIXED (Model).** `_apply_heating_donor` copied the donor's
+  *calc* `sap_heating` cluster but left the *display* rows (`main_heating`,
+  `main_heating_controls`) on the size-representative structural template —
+  incoherent with the donated system, and "Unknown" whenever the template lodged
+  no control row (exactly 721167: no `main_heating_controls` energy element
+  persisted). Now carries the donor's display heating + control alongside the
+  calc cluster.
+- **Ventilation — FIXED (Model).** The prediction never synthesised ventilation
+  — it kept the template's `sap_ventilation`, so a predicted dwelling in an
+  MEV/MVHR neighbourhood was scored + displayed as natural. New
+  `_apply_ventilation_mode` modes `mechanical_ventilation_kind` across the cohort
+  (recency/geo-weighted, mirroring glazing). Natural-vent cohorts mode to None
+  and stay natural (§2 default) — so a genuinely natural dwelling like 721167
+  correctly stays natural; the fix moves only real MEV/MVHR neighbourhoods.
+- **Main Fuel — NOT a prediction gap.** `epc_main_heating_detail.main_fuel_type`
+  *is* persisted for predicted properties (721167 → `26` = mains gas, carried
+  from the heating donor). The "Unknown" is the **same FE code→name gap as item
+  2** (the Drizzle/Next repo not mapping the fuel code), not a Model issue.
+
+Both fixes are display-only for the calculator (component-accuracy gate, corpus
+harness, and prediction e2e all green); persistence already carries
+`main_heating_controls` (energy element) and `ventilation_mechanical_ventilation_kind`,
+so the synthesised values reach the passport on the next prediction run.
diff --git a/domain/epc_prediction/epc_prediction.py b/domain/epc_prediction/epc_prediction.py
index 4261df6d..c582548c 100644
--- a/domain/epc_prediction/epc_prediction.py
+++ b/domain/epc_prediction/epc_prediction.py
@@ -70,6 +70,7 @@ class EpcPrediction:
         )
         self._apply_categorical_modes(predicted, comparables, target.coordinates)
         self._apply_glazing_mode(predicted, comparables, target.coordinates)
+        self._apply_ventilation_mode(predicted, comparables, target.coordinates)
         self._apply_heating_donor(predicted, comparables)
         self._apply_overrides(predicted, target)
         return predicted
@@ -93,7 +94,15 @@ class EpcPrediction:
         electricity tariff (`sap_energy_source.meter_type`) and hot-water flags
         live on loose top-level fields. Carry the donor's whole set, not a subset
         — otherwise a donated storage system lands on the template's single-rate
-        meter and the SAP score collapses (off-peak heat billed at the peak rate)."""
+        meter and the SAP score collapses (off-peak heat billed at the peak rate).
+
+        The system also has a DISPLAY face — the building-passport "Main Heating"
+        and "Heating Control" rows (`main_heating` / `main_heating_controls`
+        EnergyElements). These describe the same system as the calc cluster, so
+        they travel with the donor too; left on the structural template they are
+        incoherent with the donated calc heating, and `main_heating_controls`
+        shows "Unknown" whenever the size-template lodged no control row but the
+        donor does (predicted property 721167, ADR-0029 follow-up)."""
         donor = _heating_donor(comparables.members)
         if donor is None:
             return
@@ -101,6 +110,10 @@ class EpcPrediction:
         predicted.has_hot_water_cylinder = donor.epc.has_hot_water_cylinder
         predicted.solar_water_heating = donor.epc.solar_water_heating
         predicted.sap_energy_source.meter_type = donor.epc.sap_energy_source.meter_type
+        predicted.main_heating = copy.deepcopy(donor.epc.main_heating)
+        predicted.main_heating_controls = copy.deepcopy(
+            donor.epc.main_heating_controls
+        )
 
     @staticmethod
     def _apply_glazing_mode(
@@ -127,6 +140,36 @@ class EpcPrediction:
         for window in predicted.sap_windows:
             window.glazing_type = glazing
 
+    @staticmethod
+    def _apply_ventilation_mode(
+        predicted: EpcPropertyData,
+        comparables: ComparableProperties,
+        target_coordinates: Optional[Coordinates],
+    ) -> None:
+        """Set the predicted mechanical-ventilation kind to the recency- and
+        geo-weighted cohort mode. A mechanical system (MEV/MVHR) is a new-build /
+        retrofit feature that clusters by era and street (like glazing), so a
+        recent, near neighbour is the best signal for the target's system; the
+        size-representative structural template is not (it just happens to carry
+        whatever its own cert lodged). Only the kind moves — the rest of the
+        template's `sap_ventilation` (e.g. `sheltered_sides`, derived from
+        built_form) stays. A natural-vent cohort modes to None and is left
+        natural — the §2 cascade default — so this only moves genuine MEV/MVHR
+        neighbourhoods (ADR-0029 follow-up; predicted property 721167)."""
+        ventilation = predicted.sap_ventilation
+        if ventilation is None:
+            return
+        members = comparables.members
+        weights = _combine(
+            _recency_weights(members), _geo_weights(target_coordinates, members)
+        )
+        kind = _weighted_mode(
+            (_comparable_ventilation_kind(c) for c in members), weights
+        )
+        if kind is None:
+            return
+        ventilation.mechanical_ventilation_kind = kind
+
     def confidence(
         self, comparables: ComparableProperties
     ) -> PredictionConfidence:
@@ -539,6 +582,15 @@ def _comparable_modal_glazing(
     return Counter(types).most_common(1)[0][0] if types else None
 
 
+def _comparable_ventilation_kind(
+    comparable: ComparableProperty,
+) -> Optional[str]:
+    """A comparable's mechanical-ventilation kind (the `MechanicalVentilationKind`
+    enum name, e.g. "MVHR"), or None when it lodges no system (natural)."""
+    ventilation = comparable.epc.sap_ventilation
+    return ventilation.mechanical_ventilation_kind if ventilation is not None else None
+
+
 def _main_heating_detail(comparable: ComparableProperty) -> Optional[MainHeatingDetail]:
     """The primary heating system's detail row, or None when none is lodged."""
     details = comparable.epc.sap_heating.main_heating_details
diff --git a/tests/domain/epc_prediction/test_epc_prediction.py b/tests/domain/epc_prediction/test_epc_prediction.py
index 6cbb3de4..c7ffbf52 100644
--- a/tests/domain/epc_prediction/test_epc_prediction.py
+++ b/tests/domain/epc_prediction/test_epc_prediction.py
@@ -10,12 +10,14 @@ from typing import Optional, Union
 
 from datatypes.epc.domain.epc_property_data import (
     BuildingPartIdentifier,
+    EnergyElement,
     EpcPropertyData,
     MainHeatingDetail,
     SapBuildingPart,
     SapEnergySource,
     SapFloorDimension,
     SapHeating,
+    SapVentilation,
     SapWindow,
 )
 from domain.geospatial.coordinates import Coordinates
@@ -51,6 +53,9 @@ def _epc(
     has_hot_water_cylinder: bool = True,
     solar_water_heating: bool = False,
     meter_type: str = "2",
+    main_heating_label: str = "Boiler and radiators, mains gas",
+    main_heating_controls_label: Optional[str] = None,
+    mechanical_ventilation_kind: Optional[str] = None,
 ) -> EpcPropertyData:
     epc: EpcPropertyData = object.__new__(EpcPropertyData)
     epc.property_type = "2"
@@ -87,8 +92,28 @@ def _epc(
     heating.cylinder_insulation_type = 1
     heating.secondary_heating_type = None
     epc.sap_heating = heating
+    epc.main_heating = [
+        EnergyElement(
+            description=main_heating_label,
+            energy_efficiency_rating=4,
+            environmental_efficiency_rating=4,
+        )
+    ]
+    epc.main_heating_controls = (
+        EnergyElement(
+            description=main_heating_controls_label,
+            energy_efficiency_rating=4,
+            environmental_efficiency_rating=4,
+        )
+        if main_heating_controls_label is not None
+        else None
+    )
     epc.has_hot_water_cylinder = has_hot_water_cylinder
     epc.solar_water_heating = solar_water_heating
+    epc.sap_ventilation = SapVentilation(
+        mechanical_ventilation_kind=mechanical_ventilation_kind,
+        sheltered_sides=1,
+    )
     energy: SapEnergySource = object.__new__(SapEnergySource)
     energy.meter_type = meter_type
     epc.sap_energy_source = energy
@@ -538,6 +563,31 @@ def test_heating_is_a_coherent_donor_not_the_structural_template() -> None:
     assert predicted.has_hot_water_cylinder is True
 
 
+def test_ventilation_kind_follows_the_cohort_mode() -> None:
+    # Mechanical ventilation (MEV/MVHR) is a new-build / retrofit feature that
+    # clusters by era and street — like glazing — so the predicted ventilation
+    # kind takes the recency/geo-weighted cohort mode, not the size-template's.
+    # The size-closest template here is natural (None); the cohort is
+    # predominantly MVHR, so the prediction must reflect the MVHR neighbourhood
+    # rather than leave the template's empty ventilation (predicted property
+    # 721167 follow-up). Natural-vent cohorts mode to None and stay natural.
+    cohort = _cohort(
+        _epc(mechanical_ventilation_kind=None),  # template (size tie → first)
+        _epc(mechanical_ventilation_kind="MVHR"),
+        _epc(mechanical_ventilation_kind="MVHR"),
+        _epc(mechanical_ventilation_kind="MVHR"),
+    )
+
+    # Act
+    predicted: EpcPropertyData = EpcPrediction().predict(
+        PredictionTarget(postcode="LS6 1AA", property_type="2"), cohort
+    )
+
+    # Assert — the predicted kind is the cohort's MVHR mode, not the template's None.
+    assert predicted.sap_ventilation is not None
+    assert predicted.sap_ventilation.mechanical_ventilation_kind == "MVHR"
+
+
 def test_glazing_follows_the_recency_weighted_cohort_mode() -> None:
     # Arrange — an old majority single-glazed (type 1, 2015) and a recent
     # minority double-glazed (type 3, 2025). Glazing is retrofitted over time
@@ -637,3 +687,32 @@ def test_heating_donor_carries_the_donors_off_peak_meter() -> None:
     donor = _epc(meter_type="Dual", main_fuel_type=29)  # the cohort's heating
     EpcPrediction._apply_heating_donor(predicted, _cohort(donor))
     assert predicted.sap_energy_source.meter_type == "Dual"
+
+
+def test_heating_donor_carries_the_donors_display_heating_and_control() -> None:
+    # The displayed heating panel (Main Heating + Heating Control rows) describes
+    # the same system as the calc cluster, so it must travel with the donor — not
+    # be left on the size-representative structural template. Two failures
+    # otherwise: (1) the displayed heating is incoherent with the donated calc
+    # system, and (2) "Heating Control: Unknown" whenever the template lodged no
+    # control row (the donor's is dropped). Predicted property 721167 (ADR-0029
+    # follow-up): the template carried no main_heating_controls, so its passport
+    # showed Heating Control = Unknown despite a coherent gas-boiler donor.
+    predicted = _epc(
+        main_heating_label="Room heaters, electric",
+        main_heating_controls_label=None,  # template lodged no control
+    )
+    donor = _epc(
+        main_fuel_type=29,
+        main_heating_label="Boiler and radiators, mains gas",
+        main_heating_controls_label="Programmer, room thermostat and TRVs",
+    )
+
+    EpcPrediction._apply_heating_donor(predicted, _cohort(donor))
+
+    assert predicted.main_heating[0].description == "Boiler and radiators, mains gas"
+    assert predicted.main_heating_controls is not None
+    assert (
+        predicted.main_heating_controls.description
+        == "Programmer, room thermostat and TRVs"
+    )
diff --git a/tests/domain/epc_prediction/test_validation.py b/tests/domain/epc_prediction/test_validation.py
index 2cdad977..24fa0198 100644
--- a/tests/domain/epc_prediction/test_validation.py
+++ b/tests/domain/epc_prediction/test_validation.py
@@ -64,6 +64,10 @@ def _comparable(
     heating.cylinder_insulation_type = 1
     heating.secondary_heating_type = None
     epc.sap_heating = heating
+    # Display heating rows the heating-donor synthesis carries (ADR-0029
+    # follow-up); `main_heating` has no dataclass default, so a partial instance
+    # must set it. `main_heating_controls` / `sap_ventilation` default to None.
+    epc.main_heating = []
     energy: SapEnergySource = object.__new__(SapEnergySource)
     energy.photovoltaic_supply = None
     energy.photovoltaic_arrays = None