diff --git a/recommendations/tests/test_recommendation_utils.py b/recommendations/tests/test_recommendation_utils.py
index 543d5319..c42655eb 100644
--- a/recommendations/tests/test_recommendation_utils.py
+++ b/recommendations/tests/test_recommendation_utils.py
@@ -437,7 +437,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1976-1982",
         floor_area=37,
         number_habitable_rooms=2,
-        extension_count=0,
     )
 
     assert windows_case_1 == 4, f"Expected 4 windows, got {windows_case_1}"
@@ -450,7 +449,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1950-1966",
         floor_area=69,
         number_habitable_rooms=4,
-        extension_count=0,
     )
 
     assert windows_case_2 == 6, f"Expected 6 windows, got {windows_case_2}"
@@ -463,7 +461,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1967-1975",
         floor_area=56,
         number_habitable_rooms=3,
-        extension_count=0,
     )
 
     assert windows_case_3 == 5, f"Expected 5 windows, got {windows_case_3}"
@@ -476,7 +473,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1967-1975",
         floor_area=77.28,
         number_habitable_rooms=4,
-        extension_count=0,
     )
 
     assert windows_case_4 == 7, f"Expected 7 windows, got {windows_case_4}"
@@ -489,7 +485,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1950-1966",
         floor_area=88.4,
         number_habitable_rooms=5,
-        extension_count=0,
     )
 
     assert windows_case_5 == 12, f"Expected 12 windows, got {windows_case_5}"
@@ -502,7 +497,6 @@ def test_estimate_windows():
         construction_age_band="",
         floor_area=100,
         number_habitable_rooms=3,
-        extension_count=0,
     )
 
     assert windows_case_6 == 5, f"Expected 5 windows, got {windows_case_6}"
@@ -514,7 +508,6 @@ def test_estimate_windows():
         construction_age_band="England and Wales: 1967-1975",
         floor_area=85,
         number_habitable_rooms=4,
-        extension_count=0,
     )
 
     assert windows_case_7 == 10, f"Expected 10 windows, got {windows_case_7}"
@@ -526,7 +519,6 @@ def test_estimate_windows():
         construction_age_band="",
         floor_area=50,
         number_habitable_rooms=3,
-        extension_count=0,
     )
 
     assert windows_case_8 == 5, f"Expected 5 windows, got {windows_case_8}"