Added test_external_wall_area

backend/Property.py

@@ -12,7 +12,7 @@ from epc_api.client import EpcClient
 from BaseUtility import Definitions
 from recommendations.rdsap_tables import england_wales_age_band_lookup
 from recommendations.recommendation_utils import (
-    estimate_perimeter, get_wall_type, estimate_wall_area, esimtate_pitched_roof_area
+    estimate_perimeter, get_wall_type, estimate_external_wall_area, esimtate_pitched_roof_area
 )
 
 ENVIRONMENT = os.environ.get('ENVIRONMENT', 'dev')
@@ -612,8 +612,11 @@ class Property(Definitions):
             self.floor_area / self.number_of_floors, self.number_of_rooms / self.number_of_floors
         )
 
-        self.insulation_wall_area = estimate_wall_area(
+        self.insulation_wall_area = estimate_external_wall_area(
-            num_floors=self.number_of_floors, floor_height=self.floor_height, perimeter=self.perimeter
+            num_floors=self.number_of_floors,
+            floor_height=self.floor_height,
+            perimeter=self.perimeter,
+            built_form=self.data["built-form"],
         )
 
         self.pitched_roof_area = esimtate_pitched_roof_area(

recommendations/Costs.py

@@ -27,11 +27,6 @@ p2.search_address_epc()
 p1.set_basic_property_dimensions()
 p2.set_basic_property_dimensions()
 
-import pandas as pd
-
-df = pd.read_csv("/Users/khalimconn-kowlessar/Downloads/Hestia Materials - external_wall_insulation.csv")
-df = df.to_dict("records")
-
 # This data comes from SPONs
 regional_labour_variations = [
     {"Region": "Outer London (Spon’s 2023)", "Adjustment_Factor": 1.00},
@@ -120,28 +115,25 @@ class Costs:
         Calculates the total cost for cavity wall insulation based on material and labor costs,
         including contingency, preliminaries, profit, and VAT.
 
+        Because of some limitations in the SPONs data, there are no materials that can be blown through a wall,
+        therefore we have adapted similar materials, basing our estimates on 75mm cavity slabs, and have halved the
+        labour time required. That is why we still price based on wall area despite volume actually being the correct
+        metric.
+
         :return: A dictionary containing detailed cost breakdown.
         """
         # Cost per m2
         # material = {
-        #     "description": "Crown Dritherm Cavity Slab 37 (Thermal conductivity 0.037 W/mK) glass fibre batt or
+        #     "description": "cwi",
-        #     other "
-        #                    "equal; as full or partial cavity fill; including cutting and fitting around wall ties
-        #                    and "
-        #                    "retaining discs",
         #     "depth": 75,
         #     "thermal_conductivity": 0.037,
         #     "prime_cost": 5.17,
         #     "material_cost": 5.62,
-        #     "labour_cost": 2.25,
+        #     "labour_cost": 1.125,
-        #     "labour_hours": 0.13
+        #     "labour_hours": 0.065
         # }
 
         material_cost_per_m2 = material["material_cost"]
-        # wall_area = self.property.insulation_wall_area
-
-        # This is the amount of material required in m3, assuming a standard 75mm depth
-        volume = 0.075 * wall_area
 
         base_material_cost = material_cost_per_m2 * wall_area
         labour_cost = material["labour_cost"] * wall_area * self.labour_adjustment_factor

recommendations/recommendation_utils.py

@@ -527,12 +527,31 @@ def get_wall_type(
     return None
 
 
-def estimate_wall_area(num_floors, floor_height, perimeter):
+def estimate_external_wall_area(num_floors, floor_height, perimeter, built_form):
+    """
+    This method estimates the external wall area based on fundamental assumptions about the home
+
+
+    :param num_floors: Number of floors in the building.
+    :param floor_height: Height of one floor in meters.
+    :param perimeter: Total perimeter of the building on one floor in meters.
+    :param built_form: The built form of the property. This is used to determine the number of exposed walls.
+    :return:
+    """
     wall_area_one_floor = perimeter * floor_height
 
     total_wall_area = wall_area_one_floor * num_floors
 
-    return total_wall_area
+    number_exposed_walls = {
+        'End-Terrace': 3,
+        'Mid-Terrace': 2,
+        'Semi-Detached': 3,
+        'Detached': 4,
+    }
+
+    exposed_wall_area = total_wall_area * (number_exposed_walls[built_form] / 4)
+
+    return exposed_wall_area
 
 
 def calculate_r_value_per_mm(thickness_mm, thermal_conductivity_w_mK):

recommendations/tests/test_recommendation_utils.py

@@ -405,3 +405,18 @@ def test_esimtate_pitched_roof_area():
     )
 
     assert zero_roof_area2 == 0
+
+
+def test_external_wall_area():
+    # Arrange: Define the test cases
+    test_cases = [
+        (2, 3, 40, 'End-Terrace', 180),  # 3 exposed walls
+        (2, 3, 40, 'Mid-Terrace', 120),  # 2 exposed walls
+        (2, 3, 40, 'Semi-Detached', 180),  # 3 exposed walls
+        (2, 3, 40, 'Detached', 240),  # 4 exposed walls
+    ]
+
+    # Act and Assert: Run the test cases
+    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}"