diff --git a/datatypes/epc/domain/epc_property_data.py b/datatypes/epc/domain/epc_property_data.py
index d55aa1593..d6e3a70be 100644
--- a/datatypes/epc/domain/epc_property_data.py
+++ b/datatypes/epc/domain/epc_property_data.py
@@ -306,7 +306,7 @@ class SapConservatory:
 class SapWindow:
     frame_material: Optional[str]
     glazing_gap: Union[int, str]
-    orientation: Union[int, str]
+    orientation: Optional[Union[int, str]]  # SAP10 octant 1..8; None → no solar gain
     window_type: Union[int, str]
     glazing_type: Union[int, str]
     window_width: float
diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 9818c6fa7..d914bec2e 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -6167,7 +6167,7 @@ def _map_sap_window(window: Window) -> SapWindow:
     return SapWindow(
         frame_material=window.frame_type,
         glazing_gap=window.glazing_gap,
-        orientation=window.orientation,
+        orientation=_pashub_orientation_int(window.orientation),
         window_type=window.window_type,
         glazing_type=_pashub_glazing_type_int(window.glazing_type),
         window_width=window.width_m,
@@ -7153,6 +7153,23 @@ def _elmhurst_orientation_int(orientation: str) -> int:
     return _ELMHURST_ORIENTATION_TO_SAP10.get(orientation, 1)
 
 
+def _pashub_orientation_int(orientation: Optional[str]) -> Optional[int]:
+    """Map a PasHub window orientation label to the SAP10 octant code (1..8)
+    at the mapper boundary (ADR-0015). PasHub lodges it space-separated
+    ("South East") where the shared octant map keys hyphenated, so normalise
+    before lookup (mirroring `_pashub_pv_arrays`). Blank → None (the solar-
+    gains cascade skips a window with no orientation). Any uncovered non-empty
+    label strict-raises (mirroring the other `_pashub_*` coders) — passed
+    through raw, the string reaches the int-only `_orientation` and silently
+    zeroes the window's solar-gain contribution."""
+    if not orientation:
+        return None
+    code = _ELMHURST_ORIENTATION_TO_SAP10.get(orientation.replace(" ", "-"))
+    if code is None:
+        raise UnmappedPasHubLabel("window orientation", orientation)
+    return code
+
+
 # RdSAP 10 §3.7.1 (PDF p.21) — the source RdSAP data set classifies
 # each opening as "Window (vertical)" or "Roof window (inclined)" per
 # the assessor's discrete lodgement. The Elmhurst Summary PDF §11.0