diff --git a/.idea/Model.iml b/.idea/Model.iml
index 4413bb06..b0f9c00d 100644
--- a/.idea/Model.iml
+++ b/.idea/Model.iml
@@ -7,7 +7,7 @@
       <sourceFolder url="file://$MODULE_DIR$/open_uprn" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/recommendations" isTestSource="false" />
     </content>
-    <orderEntry type="jdk" jdkName="Python 3.10 (backend)" jdkType="Python SDK" />
+    <orderEntry type="jdk" jdkName="Python 3.10 (model_data)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
   <component name="PyNamespacePackagesService">
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 6f308057..1122b380 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -3,7 +3,7 @@
   <component name="Black">
     <option name="sdkName" value="Python 3.10 (backend)" />
   </component>
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.10 (backend)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.10 (model_data)" project-jdk-type="Python SDK" />
   <component name="PythonCompatibilityInspectionAdvertiser">
     <option name="version" value="3" />
   </component>
diff --git a/recommendations/recommendation_utils.py b/recommendations/recommendation_utils.py
index 100ecb15..7cfe023e 100644
--- a/recommendations/recommendation_utils.py
+++ b/recommendations/recommendation_utils.py
@@ -652,3 +652,64 @@ def esimtate_pitched_roof_area(floor_area: float, floor_height: float) -> float:
     area = 2 * (slope * wall_width)
 
     return area
+
+
+def estimate_windows(
+    property_type, built_form, construction_age_band, floor_area, number_habitable_rooms, extension_count
+):
+    # Base window count based on habitable rooms
+    window_count = number_habitable_rooms
+
+    # Additional windows for non-habitable rooms (e.g., kitchen, bathroom)
+    # Assuming most houses will have at least one kitchen and one bathroom
+    # Scale non-habitable windows with the number of habitable rooms
+    non_habitable_base = 2  # Base for kitchen and bathroom
+    extra_non_habitable = max(0, (number_habitable_rooms - 3) // 2)  # Extra for large houses
+    window_count += non_habitable_base + extra_non_habitable
+
+    # Adjustments based on built form and property type
+    if property_type in ["House", "Bungalow"] and built_form in ["Semi-Detached", "Detached"]:
+        built_form_lookup = {
+            "Semi-Detached": 3,
+            "Detached": 4,
+        }
+    else:
+        # For Flats and Maisonettes, adjustments might be less
+        built_form_lookup = {
+            "Mid-Terrace": 0,
+            "End-Terrace": 1,
+            "Semi-Detached": 1,
+            "Detached": 2,
+        }
+    window_count += built_form_lookup.get(built_form, 0)
+
+    # Adjust for floor area (larger floor area might indicate more rooms/windows)
+    if floor_area < 85:  # Small to medium properties
+        # Standard window count likely sufficient
+        pass
+    elif 85 <= floor_area <= 120:  # Medium to large properties
+        # More rooms or larger rooms likely, potentially more windows
+        window_count += 1
+    elif floor_area > 120:  # Very large properties
+        # Likely to have significantly more or larger rooms
+        window_count += 2
+
+    # Adjust for construction age band
+    if construction_age_band in ["England and Wales: before 1900", "England and Wales: 1900-1929"]:
+        # Older houses with smaller, more numerous windows
+        window_count += 1
+
+    # Adjust for extensions (each extension might add windows)
+    window_count += extension_count
+
+    # Adjustments for specific property types
+    if property_type in ["Flat", "Maisontte"]:
+        # Flats might have fewer windows due to shared walls
+        # Maisonettes might follow a similar pattern to flats or small houses
+        window_count -= 1
+
+    # Ensure window count is not negative
+    if window_count < 0:
+        raise ValueError("Window count cannot be negative.")
+
+    return window_count
diff --git a/recommendations/tests/test_recommendation_utils.py b/recommendations/tests/test_recommendation_utils.py
index aefc70b0..7c29bbb0 100644
--- a/recommendations/tests/test_recommendation_utils.py
+++ b/recommendations/tests/test_recommendation_utils.py
@@ -427,3 +427,94 @@ def test_external_wall_area():
     for num_floors, floor_height, perimeter, built_form, expected in test_cases:
         result = recommendation_utils.estimate_external_wall_area(num_floors, floor_height, perimeter, built_form)
         assert result == expected, f"Test failed for {built_form}: Expected {expected}, got {result}"
+
+
+def test_estimate_windows():
+    # Based on data from an EPR that has 4 windows
+    windows_case_1 = recommendation_utils.estimate_windows(
+        property_type="Flat",
+        built_form="Semi-Detached",
+        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}"
+
+    # Based on data from an EPR that has 7 winows, however two of the windows were very small, having areas of
+    # 0.21m^2 and 0.3m^2 respectively. We see 6 as a reasonable estimate for the number of windows
+    windows_case_2 = recommendation_utils.estimate_windows(
+        property_type="House",
+        built_form="Mid-Terrace",
+        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}"
+
+    # Based on data from an EPR on a bungalow, that has 6 windows. Two of the windows are small, both have a 0.4m^2 area
+    # and so 5 windows is an acceptable estimate
+    windows_case_3 = recommendation_utils.estimate_windows(
+        property_type="Bungalow",
+        built_form="Mid-Terrace",
+        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}"
+
+    # Based on data from an EPR on a end terrace house that has 8 windows. One of the windows is very small, with an
+    # area of 0.25 m^2 and so 7 windows is an acceptable estimate
+    windows_case_4 = recommendation_utils.estimate_windows(
+        property_type="House",
+        built_form="End-Terrace",
+        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}"
+
+    # Based on data from an EPR on a Semi-detatched house that has 11 windows based on the associated condition report
+    # Right now, we estimate 12 windows for this property
+    windows_case_5 = recommendation_utils.estimate_windows(
+        property_type="House",
+        built_form="Semi-Detached",
+        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}"
+
+    # Based on Khalim's flat which has 3 windows. There is no construction age band on the EPC. The windows are large
+    # so an estimate of 5 windows is a reasonable estimate
+    windows_case_6 = recommendation_utils.estimate_windows(
+        property_type="Flat",
+        built_form="",
+        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}"
+
+    # Based on an EPR semi detatched house though we don't have the exact number of windows. We estimate 10
+    windows_case_7 = recommendation_utils.estimate_windows(
+        property_type="House",
+        built_form="Semi-Detached",
+        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}"