basic implementation of pitched roof area estimate

backend/Property.py

@@ -11,7 +11,9 @@ from utils.s3 import read_dataframe_from_s3_parquet
 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_floors, estimate_perimeter, get_wall_type, estimate_wall_area
+from recommendations.recommendation_utils import (
+    estimate_floors, estimate_perimeter, get_wall_type, estimate_wall_area, esimtate_pitched_roof_area
+)
 
 ENVIRONMENT = os.environ.get('ENVIRONMENT', 'dev')
 EPC_AUTH_TOKEN = os.environ.get('EPC_AUTH_TOKEN')
@@ -79,6 +81,7 @@ class Property(Definitions):
         self.floor_height = None
         self.insulation_wall_area = None
         self.floor_area = None
+        self.pitched_roof_area = None
 
         if epc_client:
             self.epc_client = epc_client
@@ -587,6 +590,10 @@ class Property(Definitions):
             num_floors=self.number_of_floors, floor_height=self.floor_height, perimeter=self.perimeter
         )
 
+        self.pitched_roof_area = esimtate_pitched_roof_area(
+            floor_area=self.floor_area / self.number_of_floors, floor_height=self.floor_height
+        )
+
     def set_wall_type(self):
         """
         This method sets the wall type of the property, using a simple approach based on the wall description

recommendations/RoofRecommendations.py

@@ -54,10 +54,13 @@ class RoofRecommendations:
         u_value = get_roof_u_value(**{**self.property.roof, "age_band": self.property.age_band})
 
         if self.property.roof["is_pitched"]:
-            # We recommend loft insulation
             self.recommend_loft_insulation(u_value, insulation_thickness)
             return
 
+        if self.property.roof["is_roof_room"]:
+            self.recommend_room_roof_insulation(u_value, insulation_thickness)
+            return
+
         raise NotImplementedError("Implement me")
 
     @staticmethod
@@ -132,3 +135,21 @@ class RoofRecommendations:
                     )
 
         self.recommendations = recommendations
+
+    def recommend_room_roof_insulation(self, u_value, insulation_thickness):
+        """
+        This method recommends room in roof insulation for properties that have been identified
+        to possess a room in roof.
+
+        Because we currently have limited data about the construction of the roof, we make the following
+        assumptions:
+        1) The room in roof has a sloped roof.
+            We will make some basic estimations about the area of the roof given the floor area and the height of the
+            floors
+        2) Insulation of external walls is covered by the wall recommendation class
+        3) We assume a "Gable" roof type
+
+        :param u_value:
+        :param insulation_thickness:
+        :return:
+        """

recommendations/recommendation_utils.py

@@ -1,6 +1,7 @@
 import math
 from copy import deepcopy
 
+import numpy as np
 import pandas as pd
 
 from recommendations.rdsap_tables import (
@@ -594,3 +595,33 @@ def convert_thickness_to_numeric(string_thickness):
         return int(string_thickness.replace("+", ""))
 
     return int(string_thickness)
+
+
+def esimtate_pitched_roof_area(floor_area: float, floor_height: float) -> float:
+    """
+    This function will estimate the area of a pitched roof, given the floor area below the roof and the floor
+    height of the property.
+
+    Given limited information about the home, this is a very rough method to estimate the roof area and we
+    assume the the room is a gable roof.
+
+    We assume a roughly average pitch of 45 degrees
+
+    Note that both floor area and height should be in the same units. E.g. if floor area is meters squared,
+    floor height should be in meters
+
+    :param floor_area:      area of the home's floor
+    :param floor_height:    height of the home's floors
+    :return:                Numerical estimate of the surface area of the top of the pitched roof
+    """
+
+    # We estimate the length of the wall by just modelling the house as a square
+    wall_width = np.sqrt(floor_area)
+
+    # We're modelling the roof as two triangles where we know two of the three sides.
+    # The floor height makes up one side and half of the wall width makes up the other side
+    slope = np.sqrt(np.square(wall_width / 2) + np.square(floor_height))
+    
+    area = 2 * (slope * wall_width)
+
+    return area

recommendations/tests/test_roof_recommendations.py

@@ -192,3 +192,25 @@ class TestRoofRecommendations:
         roof_recommender6.recommend()
 
         assert len(roof_recommender6.recommendations) == 0
+
+    def test_uninsulated_room_in_roof(self):
+        property_instance7 = Property(id=0, address1="fake", postcode="fake", epc_client=Mock())
+        property_instance7.age_band = "F"
+        property_instance7.floor_area = 100
+        property_instance7.roof = {
+            'original_description': 'Roof room(s), no insulation (assumed)',
+            'clean_description': 'Roof room(s), no insulation',
+            'thermal_transmittance': None, 'thermal_transmittance_unit': None, 'is_pitched': False,
+            'is_roof_room': True, 'is_loft': False, 'is_flat': False, 'is_thatched': False, 'is_at_rafters': False,
+            'is_assumed': True, 'has_dwelling_above': False, 'is_valid': True, 'insulation_thickness': 'none'
+        }
+
+        property_instance7
+
+        roof_recommender7 = RoofRecommendations(
+            property_instance=property_instance7, materials=loft_insulation_materials
+        )
+
+        assert not roof_recommender7.recommendations
+
+        roof_recommender7.recommend()