diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 7c867ed3..a1631ee2 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -1206,8 +1206,14 @@ class EpcPropertyDataMapper:
                         orientation=w.orientation,
                         window_type=w.window_type,
                         glazing_type=w.glazing_type,
-                        window_width=0.0,
-                        window_height=0.0,
+                        # ADR-0027: the 7 rich certs lodge a real per-window
+                        # window_area (Measurement) — use it directly as
+                        # geometry (width = area, height = 1.0, matching the
+                        # synthesis convention) rather than the placeholder
+                        # windowless 0x0 that modelled these data-richest certs
+                        # as having no glazing at all.
+                        window_width=_measurement_value(w.window_area),
+                        window_height=1.0,
                         draught_proofed=False,
                         window_location=w.window_location,
                         window_wall_type=0,
diff --git a/datatypes/epc/domain/tests/test_from_rdsap_schema.py b/datatypes/epc/domain/tests/test_from_rdsap_schema.py
index fb4cce54..924fdc30 100644
--- a/datatypes/epc/domain/tests/test_from_rdsap_schema.py
+++ b/datatypes/epc/domain/tests/test_from_rdsap_schema.py
@@ -1399,3 +1399,28 @@ class TestRdSap20_0_0ReducedFieldSynthesis:
 
         # Assert
         assert isinstance(result, EpcPropertyData)
+
+    def test_rich_cert_uses_lodged_window_area_for_geometry(self) -> None:
+        # Arrange — ADR-0027: 7/1000 certs DO lodge a per-window sap_windows
+        # array (window_area as a Measurement). Those windows must use their
+        # lodged area as geometry (width = area, height = 1.0) rather than being
+        # synthesised — and must NOT be modelled windowless (width=height=0,
+        # the prior placeholder behaviour for the certs that actually carry the
+        # richest window data).
+        corpus = _load_20_0_0_corpus()
+        if not corpus:
+            pytest.skip("no RdSAP-Schema-20.0.0 corpus harvested")
+        cert = next((c for c in corpus if c.get("sap_windows")), None)
+        if cert is None:
+            pytest.skip("no corpus cert lodging sap_windows")
+        lodged = cert["sap_windows"]
+        expected_total = sum(w["window_area"]["value"] for w in lodged)
+
+        # Act
+        result = EpcPropertyDataMapper.from_api_response(cert)
+
+        # Assert — one domain window per lodged window, total glazed area
+        # (width x height, height=1) preserved from the lodged measurement.
+        assert len(result.sap_windows) == len(lodged)
+        total_area = sum(w.window_width * w.window_height for w in result.sap_windows)
+        assert total_area == pytest.approx(expected_total)