diff --git a/model_data/epc_attributes/WindowAttributes.py b/model_data/epc_attributes/WindowAttributes.py
index 8d5eb252..2f433eb0 100644
--- a/model_data/epc_attributes/WindowAttributes.py
+++ b/model_data/epc_attributes/WindowAttributes.py
@@ -20,7 +20,8 @@ class WindowAttributes(Definitions):
     WELSH_TEXT = {
         "gwydrau dwbl llawn": "full double glazing",
         "gwydrau dwbl rhannol": "partial double glazing",
-        "gwydrau dwbl gan mwyaf": "Mostly double glazing",
+        "gwydrau dwbl gan mwyaf": "mostly double glazing",
+        "rhai gwydrau dwbl": "some double glazing",
         "gwydrau sengl": "single glazed",
         "ffenestri perfformiad uchel": "high performance glazing",
     }
diff --git a/model_data/tests/test_data/test_window_attributes_cases.py b/model_data/tests/test_data/test_window_attributes_cases.py
index c25791f8..150eb757 100644
--- a/model_data/tests/test_data/test_window_attributes_cases.py
+++ b/model_data/tests/test_data/test_window_attributes_cases.py
@@ -46,4 +46,6 @@ windows_cases = [
      'no_data': False},
     {'original_description': 'Ffenestri perfformiad uchel', 'has_glazing': True, 'glazing_coverage': 'full',
      'glazing_type': 'high performance', 'no_data': False},
+    {'original_description': 'Rhai gwydrau dwbl', 'has_glazing': True, 'glazing_coverage': 'partial',
+     'glazing_type': 'double', 'no_data': False},
 ]