diff --git a/city_model_structure/attributes/domestic_hot_water_facility.py b/city_model_structure/attributes/domestic_hot_water_facility.py
new file mode 100644
index 00000000..ecb3a588
--- /dev/null
+++ b/city_model_structure/attributes/domestic_hot_water_facility.py
@@ -0,0 +1,53 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class DomesticHotWaterFacility:
+  """
+  Domestic Hot Water facilities class
+  """
+
+  def __init__(self, number_of_baths, number_of_showers, number_of_basin, water_storage_volume):
+    """
+    Constructor
+    """
+
+    self._number_of_baths = number_of_baths
+    self._number_of_showers = number_of_showers
+    self._number_of_basin = number_of_basin
+    self._water_storage_volume = water_storage_volume
+
+  @property
+  def number_of_baths(self):
+    """
+    Get number of baths of a building unit
+    :return: number of baths
+    """
+    return self._number_of_baths
+
+  @property
+  def number_of_showers(self):
+      """
+      Get number of showers of a building unit
+      :return: number of showers
+      """
+      return self._number_of_showers
+
+  @property
+  def number_of_basin(self):
+      """
+      Get number of wash basins of a building unit
+      :return: number of wash basins
+      """
+      return self._number_of_basin
+
+  @property
+  def water_storage_volume(self):
+      """
+      Get the volume of water storage
+      :return: volume of water storage
+      """
+      return self._water_storage_volume
diff --git a/city_model_structure/attributes/electric_appliances_facilities.py b/city_model_structure/attributes/electric_appliances_facilities.py
new file mode 100644
index 00000000..357968bd
--- /dev/null
+++ b/city_model_structure/attributes/electric_appliances_facilities.py
@@ -0,0 +1,26 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class appliances_facilities:
+  """
+  Electric appliance facilities class
+  """
+
+  def __init__(self, appliance_electric_power):
+    """
+    Constructor
+    """
+
+    self._appliance_electric_power = appliance_electric_power
+
+  @property
+  def appliance_electric_power(self):
+     """
+     Get appliances electric power
+     :return: appliances electric power
+     """
+     return self._appliance_electric_power
diff --git a/city_model_structure/attributes/facility.py b/city_model_structure/attributes/facility.py
new file mode 100644
index 00000000..186d8dfe
--- /dev/null
+++ b/city_model_structure/attributes/facility.py
@@ -0,0 +1,59 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class Facility:
+  """
+  facilities class
+  """
+
+  def __init__(self, operation_schedules, convective_fraction, latent_fraction,
+               radiant_fraction, total_value_of_heat_dissipation):
+    self._operation_schedules = operation_schedules
+    self._convective_fraction = convective_fraction
+    self._latent_fraction = latent_fraction
+    self._radiant_fraction = radiant_fraction
+    self._total_value_of_heat_dissipation = total_value_of_heat_dissipation
+
+  @property
+  def operation_schedules(self):
+    """
+    Get operation schedules of the facilities
+    :return: operation schedules
+    """
+    return self._operation_schedules
+
+  @property
+  def convective_fraction(self):
+      """
+      Get convective fraction value
+      :return: convective fraction
+      """
+      return self._convective_fraction
+
+  @property
+  def latent_fraction(self):
+      """
+      Get latent fraction value
+      :return: latent fraction
+      """
+      return self._latent_fraction
+
+  @property
+  def radiant_fraction(self):
+      """
+      Get radiant fraction value
+      :return: radiant fraction
+      """
+      return self._radiant_fraction
+
+  @property
+  def total_value_of_heat_dissipation(self):
+      """
+      Get heat dissipation value
+      :return: heat dissipation
+      """
+      return self._total_value_of_heat_dissipation
diff --git a/city_model_structure/attributes/household.py b/city_model_structure/attributes/household.py
new file mode 100644
index 00000000..81f9a19b
--- /dev/null
+++ b/city_model_structure/attributes/household.py
@@ -0,0 +1,36 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class household:
+  """
+  Household class
+  """
+
+  def __init__(self, resident_type, household_type):
+    """
+    Constructor
+    """
+
+    self._resident_type = resident_type
+    self._household_type = household_type
+
+
+  @property
+  def resident_type(self):
+     """
+     Get resident type
+     :return: resident type
+     """
+     return self._resident_type
+
+  @property
+  def household_type(self):
+     """
+     Get household type
+     :return: household type
+     """
+     return self._household_type
\ No newline at end of file
diff --git a/city_model_structure/attributes/hvac_facility.py b/city_model_structure/attributes/hvac_facility.py
new file mode 100644
index 00000000..9bde3160
--- /dev/null
+++ b/city_model_structure/attributes/hvac_facility.py
@@ -0,0 +1,36 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class HvacFacility:
+  """
+  HVAC facilities class
+  """
+
+  def __init__(self, temperature_setpoints, hvac_schedules):
+    """
+    Constructor
+    """
+
+    self._temperature_setpoints = temperature_setpoints
+    self._hvac_schedules = hvac_schedules
+
+  @property
+  def temperature_setpoints(self):
+    """
+    Get temperature setpoints
+    :return: temperature setpoints
+    """
+    return self._temperature_setpoints
+
+  @property
+  def hvac_schedules(self):
+      """
+      Get HVAC schedules
+      :return: HVAC schedules
+      """
+      return self._hvac_schedules
+
diff --git a/city_model_structure/attributes/internal_gains.py b/city_model_structure/attributes/internal_gains.py
new file mode 100644
index 00000000..4f4b1696
--- /dev/null
+++ b/city_model_structure/attributes/internal_gains.py
@@ -0,0 +1,84 @@
+"""
+InternalGains module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+
+
+class InternalGains:
+  """
+  InternalGains class
+  """
+  def __init__(self):
+    self._average_internal_gain = None
+    self._convective_fraction = None
+    self._radiative_fraction = None
+    self._latent_fraction = None
+
+  @property
+  def average_internal_gain(self):
+    """
+    Get internal gains average internal gain in w/m2
+    :return: float
+    """
+    return self._average_internal_gain
+
+  @average_internal_gain.setter
+  def average_internal_gain(self, value):
+    """
+    Set internal gains average internal gain in w/m2
+    :param value: float
+    :return: None
+    """
+    self._average_internal_gain = value
+
+  @property
+  def convective_fraction(self):
+    """
+    Get internal gains convective fraction
+    :return: float
+    """
+    return self._convective_fraction
+
+  @convective_fraction.setter
+  def convective_fraction(self, value):
+    """
+    Set internal gains convective fraction
+    :param value: float
+    :return: None
+    """
+    self._convective_fraction = value
+
+  @property
+  def radiative_fraction(self):
+    """
+    Get internal gains radiative fraction
+    :return: float
+    """
+    return self._radiative_fraction
+
+  @radiative_fraction.setter
+  def radiative_fraction(self, value):
+    """
+    Set internal gains convective fraction
+    :param value: float
+    :return: None
+    """
+    self._radiative_fraction = value
+
+  @property
+  def latent_fraction(self):
+    """
+    Get internal gains latent fraction
+    :return: float
+    """
+    return self._latent_fraction
+
+  @latent_fraction.setter
+  def latent_fraction(self, value):
+    """
+    Set internal gains latent fraction
+    :param value: float
+    :return: None
+    """
+    self._latent_fraction = value
diff --git a/city_model_structure/attributes/layer.py b/city_model_structure/attributes/layer.py
new file mode 100644
index 00000000..54bc532d
--- /dev/null
+++ b/city_model_structure/attributes/layer.py
@@ -0,0 +1,49 @@
+"""
+Layers module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from city_model_structure.attributes.material import Material
+
+
+class Layer:
+  """
+  Layer class
+  """
+  def __init__(self):
+    self._material = None
+    self._thickness = None
+
+  @property
+  def material(self) -> Material:
+    """
+    Get layer material
+    :return: Material
+    """
+    return self._material
+
+  @material.setter
+  def material(self, value):
+    """
+    Set layer material
+    :param value: Material
+    :return: None
+    """
+    self._material = value
+
+  @property
+  def thickness(self):
+    """
+    Get layer thickness in meters
+    :return: float
+    """
+    return self._thickness
+
+  @thickness.setter
+  def thickness(self, value):
+    """
+    Get layer thickness in meters
+    :param value: float
+    :return: None
+    """
+    self._thickness = value
diff --git a/city_model_structure/attributes/lighting_facilities.py b/city_model_structure/attributes/lighting_facilities.py
new file mode 100644
index 00000000..62a84a04
--- /dev/null
+++ b/city_model_structure/attributes/lighting_facilities.py
@@ -0,0 +1,26 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class lighting_facilities:
+  """
+  Lighting facilities class
+  """
+
+  def __init__(self, electric_power):
+    """
+    Constructor
+    """
+
+    self._electric_power = electric_power
+
+  @property
+  def electric_power(self):
+     """
+     Get lighting electric power
+     :return: lighting electric power
+     """
+     return self._electric_power
diff --git a/city_model_structure/attributes/material.py b/city_model_structure/attributes/material.py
new file mode 100644
index 00000000..ddb23ba9
--- /dev/null
+++ b/city_model_structure/attributes/material.py
@@ -0,0 +1,156 @@
+"""
+Material module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+
+
+class Material:
+  """
+  Material class
+  """
+  def __init__(self):
+    self._conductivity = None
+    self._specific_heat = None
+    self._density = None
+    self._solar_absorptance = None
+    self._thermal_absorptance = None
+    self._visible_absorptance = None
+    self._no_mass = False
+    self._thermal_resistance = None
+
+  @property
+  def conductivity(self):
+    """
+     Get material conductivity in W/mK
+     :return: float
+    """
+    return self._conductivity
+
+  @conductivity.setter
+  def conductivity(self, value):
+    """
+    Set material conductivity in W/mK
+    :param value: float
+    :return: None
+    """
+    self._conductivity = value
+
+  @property
+  def specific_heat(self):
+    """
+    Get material conductivity in J/kgK
+    :return: float
+    """
+    return self._specific_heat
+
+  @specific_heat.setter
+  def specific_heat(self, value):
+    """
+    Get material conductivity in J/kgK
+    :param value: float
+    :return: None
+    """
+    self._specific_heat = value
+
+  @property
+  def density(self):
+    """
+    Get material density in kg/m3
+    :return: float
+    """
+    return self._density
+
+  @density.setter
+  def density(self, value):
+    """
+    Set material density in kg/m3
+    :param value: float
+    :return: None
+    """
+    self._density = value
+
+  @property
+  def solar_absorptance(self):
+    """
+    Get material solar absorptance
+    :return: float
+    """
+    return self._solar_absorptance
+
+  @solar_absorptance.setter
+  def solar_absorptance(self, value):
+    """
+    Set material solar absorptance
+    :param value: float
+    :return: None
+    """
+    self._solar_absorptance = value
+
+  @property
+  def thermal_absorptance(self):
+    """
+    Get material thermal absorptance
+    :return: float
+    """
+    return self._thermal_absorptance
+
+  @thermal_absorptance.setter
+  def thermal_absorptance(self, value):
+    """
+    Set material thermal absorptance
+    :param value: float
+    :return: None
+    """
+    self._thermal_absorptance = value
+
+  @property
+  def visible_absorptance(self):
+    """
+    Get material visible absorptance
+    :return: float
+    """
+    return self._visible_absorptance
+
+  @visible_absorptance.setter
+  def visible_absorptance(self, value):
+    """
+    Set material visible absorptance
+    :param value: float
+    :return: None
+    """
+    self._visible_absorptance = value
+
+  @property
+  def no_mass(self):
+    """
+    Get material no mass flag
+    :return: Boolean
+    """
+    return self._no_mass
+
+  @no_mass.setter
+  def no_mass(self, value):
+    """
+    Set material no mass flag
+    :param value: Boolean
+    :return: None
+    """
+    self._no_mass = value
+
+  @property
+  def thermal_resistance(self):
+    """
+    Get material thermal resistance in m2K/W
+    :return: float
+    """
+    return self._thermal_resistance
+
+  @thermal_resistance.setter
+  def thermal_resistance(self, value):
+    """
+    Set material thermal resistance in m2K/W
+    :param value: float
+    :return: None
+    """
+    self._thermal_resistance = value
diff --git a/city_model_structure/attributes/occupancy.py b/city_model_structure/attributes/occupancy.py
new file mode 100644
index 00000000..6560e302
--- /dev/null
+++ b/city_model_structure/attributes/occupancy.py
@@ -0,0 +1,127 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class Occupancy:
+  """
+  Occupancy class
+  """
+
+  def __init__(self, internal_heat_gain, heat_dissipation, occupant_rate, occupant_type, occupant_zone,
+               number_of_occupants, arrival_time=None, departure_time=None, break_time=None, day_of_week=None,
+               pd_of_meetings_duration=None, occupant_schedule=None):
+    """
+    Constructor
+    """
+
+    self._internal_heat_gain = internal_heat_gain
+    self._heat_dissipation = heat_dissipation
+    self._occupant_rate = occupant_rate
+    self._occupant_type = occupant_type
+    self._occupant_zone = occupant_zone
+    self._occupant_schedule = occupant_schedule
+    self._number_of_occupants = number_of_occupants
+    self._arrival_time = arrival_time
+    self._departure_time = departure_time
+    self._break_time = break_time
+    self._day_of_week = day_of_week
+    self._pd_of_meetings_duration = pd_of_meetings_duration
+
+  @property
+  def internal_heat_gain(self):
+    """
+    Get internal heat gain of occupants
+    :return: occupant heat gain
+    """
+    return self._internal_heat_gain
+
+  @property
+  def heat_dissipation(self):
+    """
+    Get heat dissipation of occupants
+    :return: heat dissipation
+    """
+    return self._heat_dissipation
+
+  @property
+  def occupant_rate(self):
+    """
+    Get rate of occupancy
+    :return: rate of occupancy
+    """
+    return self._occupant_rate
+
+  @property
+  def occupant_type(self):
+    """
+    Get type of occupancy
+    :return: type of occupancy
+    """
+    return self._occupant_type
+
+  @property
+  def occupant_zone(self):
+    """
+    Get the zone that occupant is in it
+    :return: occupant zone
+    """
+    return self._occupant_zone
+
+  @property
+  def occupant_schedule(self):
+    """
+    Get the schedule when an occupant is in a zone
+    :return: occupant schedule
+    """
+    return self._occupant_schedule
+
+  @property
+  def number_of_occupants(self):
+    """
+    Get the number of occupants
+    :return: number of occupants
+    """
+    return self._number_of_occupants
+
+  @property
+  def arrival_time(self):
+    """
+    Get the arrival time of the occupant (for office building)
+    :return: arrival time
+    """
+    return self._arrival_time
+
+  @property
+  def departure_time(self):
+    """
+    Get the departure time of the occupant (for office building)
+    :return: departure time
+    """
+    return self._departure_time
+
+  @property
+  def break_time(self):
+    """
+    Get the lunch or break time of the occupant (for office building)
+    :return: break time
+    """
+    return self._break_time
+
+  @property
+  def day_of_week(self):
+    """
+    Get the day of the week
+    :return: day of the week
+    """
+    return self._day_of_week
+
+  @property
+  def pd_of_meetings_duration(self):
+    """
+    Get the probability distribution of the meeting duration
+    :return: probability distribution of the meeting duration
+    """
+    return self._pd_of_meetings_duration
diff --git a/city_model_structure/attributes/polyhedron.py b/city_model_structure/attributes/polyhedron.py
new file mode 100644
index 00000000..a3ba84db
--- /dev/null
+++ b/city_model_structure/attributes/polyhedron.py
@@ -0,0 +1,116 @@
+"""
+Polyhedron module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+import numpy as np
+from trimesh import Trimesh
+
+from helpers.geometry_helper import GeometryHelper
+
+
+class Polyhedron:
+  """
+  Polyhedron class
+  """
+  def __init__(self, surfaces):
+    self._surfaces = list(surfaces)
+    self._polygons = [s.polygon for s in surfaces]
+    self._polyhedron = None
+    self._volume = None
+    self._faces = None
+    self._vertices = None
+    self._mesh = None
+    self._centroid = None
+    self._max_z = None
+    self._geometry = GeometryHelper()
+
+  def _position_of(self, point):
+    vertices = self.vertices
+    for i in range(len(vertices)):
+      if self._geometry.almost_equal(vertices[i], point):
+        return i
+    return -1
+
+  @property
+  def vertices(self) -> np.ndarray:
+    """
+    Polyhedron vertices
+    :return: np.ndarray(int)
+    """
+    if self._vertices is None:
+      vertices, self._vertices = [], []
+      _ = [vertices.extend(s.points) for s in self._surfaces]
+      for vertex_1 in vertices:
+        found = False
+        for vertex_2 in self._vertices:
+          found = False
+          if self._geometry.almost_equal(vertex_1, vertex_2):
+            found = True
+            break
+        if not found:
+          self._vertices.append(vertex_1)
+      self._vertices = np.asarray(self._vertices)
+    return self._vertices
+
+  @property
+  def faces(self) -> np.ndarray:
+    """
+    Polyhedron faces
+    :return: np.ndarray([int])
+    """
+    if self._faces is None:
+      self._faces = []
+      for surface in self._surfaces:
+        face = []
+        points = surface.points
+        for point in points:
+          face.append(self._position_of(point))
+        self._faces.append(face)
+    return self._faces
+
+  @property
+  def _polyhedron_mesh(self):
+    if self._mesh is None:
+      self._mesh = Trimesh(vertices=self.vertices, faces=self.faces)
+    return self._mesh
+
+  @property
+  def volume(self):
+    """
+    Polyhedron volume in cubic meters
+    :return: float
+    """
+    if self._volume is None:
+      if not self._polyhedron_mesh.is_volume:
+        print('The geometry is not a closed volume')
+        self._volume = np.inf
+      else:
+        self._volume = self._polyhedron_mesh.volume
+    return self._volume
+
+  @property
+  def max_z(self):
+    """
+    Polyhedron maximal z value
+    :return: float
+    """
+    bounds = self._polyhedron_mesh.bounds
+    z_max = max(bounds[:, 2])
+    return z_max
+
+  @property
+  def centroid(self):
+    """
+    Polyhedron centroid
+    :return: [x,y,z]
+    """
+    return self._polyhedron_mesh.centroid
+
+  def export(self, full_path):
+    """
+    Export the polyhedron to stl given file
+    :param full_path: str
+    :return: None
+    """
+    self._polyhedron_mesh.export(full_path)
diff --git a/city_model_structure/attributes/schedule_value.py b/city_model_structure/attributes/schedule_value.py
new file mode 100644
index 00000000..c949bdaa
--- /dev/null
+++ b/city_model_structure/attributes/schedule_value.py
@@ -0,0 +1,34 @@
+"""
+Building module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Sanam Dabirian sanam.dabirian@mail.concordia.ca
+"""
+
+
+class ScheduleValue:
+  """
+  Schedule Values class
+  """
+
+  def __init__(self, hour, probability):
+    """
+    Constructor
+    """
+    self._hour = hour
+    self._probability = probability
+
+  @property
+  def hour(self):
+    """
+    Get hours
+    :return: hour of a day
+    """
+    return self._hour
+
+  @property
+  def probability(self):
+      """
+      Get probabilities of occupants' presence
+          :return: occupants' presence probabilities
+      """
+      return self._probability
\ No newline at end of file
diff --git a/city_model_structure/attributes/surface.py b/city_model_structure/attributes/surface.py
new file mode 100644
index 00000000..de206820
--- /dev/null
+++ b/city_model_structure/attributes/surface.py
@@ -0,0 +1,443 @@
+"""
+Surface module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from __future__ import annotations
+from typing import Union
+
+import numpy as np
+import pyny3d.geoms as pn
+import pandas as pd
+import helpers.constants as cte
+
+from helpers.geometry_helper import GeometryHelper
+
+
+class Surface:
+  """
+  Surface class
+  """
+  def __init__(self, coordinates, surface_type=None, name=None, swr='0.2', remove_last=True, is_projected=False):
+    self._coordinates = coordinates
+    self._type = surface_type
+    self._name = name
+    self._swr = swr
+    self._remove_last = remove_last
+    self._is_projected = is_projected
+    self._geometry_helper = GeometryHelper()
+    self._polygon = None
+    self._ground_polygon = None
+    self._area = None
+    self._points = None
+    self._ground_points = None
+    self._points_list = None
+    self._normal = None
+    self._azimuth = None
+    self._inclination = None
+    self._area_above_ground = None
+    self._area_below_ground = None
+    self._parent = None
+    self._shapely = None
+    self._projected_surface = None
+    self._min_x = None
+    self._min_y = None
+    self._min_z = None
+    self._shared_surfaces = []
+    self._global_irradiance = pd.DataFrame()
+    self._global_irradiance_hour = np.zeros(8760)
+    self._global_irradiance_month = np.zeros(12)
+    self._ground_coordinates = (self.min_x, self.min_y, self.min_z)
+
+  def parent(self, parent, surface_id):
+    """
+    Assign a city object as surface parent and a surface id
+    :param parent:  CityObject
+    :param surface_id: str
+    :return: None
+    """
+    self._parent = parent
+    self._name = str(surface_id)
+
+  @property
+  def name(self):
+    """
+    Surface name
+    :return: str
+    """
+    if self._name is None:
+      raise Exception('surface has no name')
+    return self._name
+
+  @property
+  def swr(self):
+    """
+    Get surface short wave reflectance
+    :return: float
+    """
+    return self._swr
+
+  @swr.setter
+  def swr(self, value):
+    """
+    Set surface short wave reflectance
+    :param value: float
+    :return: None
+    """
+    self._swr = value
+
+  @property
+  def points(self) -> np.ndarray:
+    """
+    Surface point matrix
+    :return: np.ndarray
+    """
+    if self._points is None:
+      self._points = np.fromstring(self._coordinates, dtype=float, sep=' ')
+      self._points = GeometryHelper.to_points_matrix(self._points, self._remove_last)
+    return self._points
+
+  def _min_coord(self, axis):
+    if axis == 'x':
+      axis = 0
+    elif axis == 'y':
+      axis = 1
+    else:
+      axis = 2
+    min_coordinate = ''
+    for point in self.points:
+      if min_coordinate == '':
+        min_coordinate = point[axis]
+      elif min_coordinate > point[axis]:
+        min_coordinate = point[axis]
+    return min_coordinate
+
+  @property
+  def min_x(self):
+    """
+    Surface minimal x value
+    :return: float
+    """
+    if self._min_x is None:
+      self._min_x = self._min_coord('x')
+    return self._min_x
+
+  @property
+  def min_y(self):
+    """
+    Surface minimal y value
+    :return: float
+    """
+    if self._min_y is None:
+      self._min_y = self._min_coord('y')
+    return self._min_y
+
+  @property
+  def min_z(self):
+    """
+    Surface minimal z value
+    :return: float
+    """
+    if self._min_z is None:
+      self._min_z = self._min_coord('z')
+    return self._min_z
+
+  @property
+  def ground_points(self) -> np.ndarray:
+    """
+    Surface grounded points matrix
+    :return: np.ndarray
+    """
+    if self._ground_points is None:
+      coordinates = ''
+      for point in self.points:
+        x = point[0] - self._ground_coordinates[0]
+        y = point[1] - self._ground_coordinates[1]
+        z = point[2] - self._ground_coordinates[2]
+        if coordinates != '':
+          coordinates = coordinates + ' '
+        coordinates = coordinates + str(x) + ' ' + str(y) + ' ' + str(z)
+      self._ground_points = np.fromstring(coordinates, dtype=float, sep=' ')
+      self._ground_points = GeometryHelper.to_points_matrix(self._ground_points, False)
+    return self._ground_points
+
+  @property
+  def points_list(self) -> np.ndarray:
+    """
+    Surface point list
+    :return: np.ndarray
+    """
+    if self._points_list is None:
+      s = self.points
+      self._points_list = np.reshape(s, len(s) * 3)
+    return self._points_list
+
+  @property
+  def polygon(self) -> Union[pn.Polygon, None]:
+    """
+    Surface polygon
+    :return: None or pyny3d.Polygon
+    """
+    if self._polygon is None:
+      try:
+        self._polygon = pn.Polygon(self.points)
+      except ValueError:
+        # is not really a polygon but a line so just return none
+        self._polygon = None
+    return self._polygon
+
+  @property
+  def ground_polygon(self) -> Union[pn.Polygon, None]:
+    """
+    Surface grounded polygon
+    :return: None or pyny3d.Polygon
+    """
+    if self._ground_polygon is None:
+      try:
+        self._ground_polygon = pn.Polygon(self.ground_points)
+      except ValueError:
+        # is not really a polygon but a line so just return none
+        self._ground_polygon = None
+    return self._ground_polygon
+
+  @property
+  def area(self):
+    """
+    Surface area in square meters
+    :return: float
+    """
+    if self._area is None:
+      self._area = self.polygon.get_area()
+    return self._area
+
+  def _is_almost_same_terrain(self, terrain_points, ground_points):
+    equal = 0
+    for terrain_point in terrain_points:
+      for ground_point in ground_points:
+        if self._geometry_helper.almost_equal(terrain_point, ground_point):
+          equal += 1
+    return equal == len(terrain_points)
+
+  @property
+  def _is_terrain(self):
+    for t_points in self._parent.terrains:
+      if len(t_points) == len(self.points) and self._is_almost_same_terrain(t_points, self.points):
+        return True
+    return False
+
+  @property
+  def area_above_ground(self):
+    """
+    Surface area above ground in square meters
+    :return: float
+    """
+    if self._area_above_ground is None:
+      self._area_above_ground = self.area - self.area_below_ground
+    return self._area_above_ground
+
+  @property
+  def area_below_ground(self):
+    """
+    Surface area below ground in square meters
+    :return: float
+    """
+    if self._area_below_ground is None:
+      self._area_below_ground = 0.0
+      if self._is_terrain:
+        self._area_below_ground = self.area
+    return self._area_below_ground
+
+  @property
+  def normal(self) -> np.ndarray:
+    """
+    Surface normal vector
+    :return: np.ndarray
+    """
+    if self._normal is None:
+      points = self.points
+      cross_product = np.cross(points[1] - points[0], points[2] - points[0])
+      self._normal = cross_product / np.linalg.norm(cross_product)
+    return self._normal
+
+  @property
+  def azimuth(self):
+    """
+    Surface azimuth in radians
+    :return: float
+    """
+    if self._azimuth is None:
+      normal = self.normal
+      self._azimuth = np.arctan2(normal[1], normal[0])
+    return self._azimuth
+
+  @property
+  def inclination(self):
+    """
+    Surface inclination in radians
+    :return: float
+    """
+    if self._inclination is None:
+      self._inclination = np.arccos(self.normal[2])
+    return self._inclination
+
+  @property
+  def type(self):
+    """
+    Surface type Ground, Wall or Roof
+    :return: str
+    """
+    if self._type is None:
+      grad = np.rad2deg(self.inclination)
+      if grad >= 170:
+        self._type = 'Ground'
+      elif 80 <= grad <= 100:
+        self._type = 'Wall'
+      else:
+        self._type = 'Roof'
+    return self._type
+
+  def add_shared(self, surface, intersection_area):
+    """
+    Add a given surface and shared area in percent to this surface.
+    :param surface:
+    :param intersection_area:
+    :return:
+    """
+    percent = intersection_area / self.area
+    self._shared_surfaces.append((percent, surface))
+
+  def shared(self, surface):
+    """
+    Check if given surface share some area with this surface
+    :param surface: Surface
+    :return: None
+    """
+    if self.type != 'Wall' or surface.type != 'Wall':
+      return
+    if self._geometry_helper.is_almost_same_surface(self, surface):
+      intersection_area = self.intersect(surface).area
+      self.add_shared(surface, intersection_area)
+      surface.add_shared(self, intersection_area)
+
+  @property
+  def global_irradiance_hour(self):
+    """
+    Get surface global irradiance hour in Wh/m2
+    :return: float
+    """
+    return self._global_irradiance_hour
+
+  @global_irradiance_hour.setter
+  def global_irradiance_hour(self, value):
+    """
+    Set surface global irradiance per hour in Wh/m2
+    :param value: float
+    :return: None
+    """
+    self._global_irradiance_hour = value
+
+  @property
+  def global_irradiance_month(self):
+    """
+    Get surface global irradiance per month in Wh/m2
+    :return: float
+    """
+    return self._global_irradiance_month
+
+  @global_irradiance_month.setter
+  def global_irradiance_month(self, value):
+    """
+    Set surface global irradiance per month in Wh/m2
+    :param value: float
+    :return: None
+    """
+    self._global_irradiance_month = value
+
+  def global_irradiance(self, time_scale):
+    """
+    Get surface global irradiance in Wh/m2 in a defined time_scale
+    :param time_scale: string.
+    :return: DataFrame(float)
+    """
+    if time_scale == cte.time_scale['hour']:
+      self._global_irradiance = self.global_irradiance_hour
+    elif time_scale == cte.time_scale['month']:
+      self._global_irradiance = self.global_irradiance_month
+    else:
+      raise NotImplementedError
+    return self._global_irradiance
+
+  @property
+  def shapely(self) -> Union[None, pn.Polygon]:
+    """
+    Surface shapely (Z projection)
+    :return: None or pyny3d.Polygon
+    """
+    if self.polygon is None:
+      return None
+    if self._shapely is None:
+      self._shapely = self.polygon.get_shapely()
+    return self._shapely
+
+  @staticmethod
+  def _polygon_to_surface(polygon) -> Surface:
+    coordinates = ''
+    for coordinate in polygon.exterior.coords:
+      if coordinates != '':
+        coordinates = coordinates + ' '
+      coordinates = coordinates + str(coordinate[0]) + ' ' + str(coordinate[1]) + ' 0.0'
+    return Surface(coordinates, remove_last=False)
+
+  @property
+  def projection(self) -> Surface:
+    """
+    Projected surface (Z projection)
+    :return: Surface
+    """
+    if self._is_projected:
+      return self
+    if self._projected_surface is None:
+      shapely = self.shapely
+      if shapely is not None:
+        self._projected_surface = self._polygon_to_surface(shapely)
+    return self._projected_surface
+
+  def intersect(self, surface) -> Union[Surface, None]:
+    """
+    Get the intersection surface, if any, between the given surface and this surface
+    :param surface: Surface
+    :return: None or Surface
+    """
+    min_x = min(self.min_x, surface.min_x)
+    min_y = min(self.min_y, surface.min_y)
+    min_z = min(self.min_z, surface.min_z)
+    self._ground_coordinates = (min_x, min_y, min_z)
+    surface._ground_coordinates = (min_x, min_y, min_z)
+    origin = (0, 0, 0)
+    azimuth = self.azimuth - (np.pi / 2)
+    while azimuth < 0:
+      azimuth += (np.pi / 2)
+    inclination = self.inclination - np.pi
+    while inclination < 0:
+      inclination += np.pi
+    polygon1 = self.ground_polygon.rotate(azimuth, 'z', origin).rotate(inclination, 'x', origin)
+    polygon2 = surface.ground_polygon.rotate(azimuth, 'z', origin).rotate(inclination, 'x', origin)
+    try:
+      coordinates = ''
+      intersection = pn.Surface([polygon1]).intersect_with(polygon2)
+      if len(intersection) == 0:
+        return None
+      for coordinate in pn.Surface([polygon1]).intersect_with(polygon2)[0]:
+        if coordinates != '':
+          coordinates = coordinates + ' '
+        coordinates = coordinates + str(coordinate[0]) + ' ' + str(coordinate[1]) + ' 0.0'
+      if coordinates == '':
+        return None
+      intersect_surface = Surface(coordinates, remove_last=False)
+      if intersect_surface.polygon is None:
+        return None
+
+      return Surface(coordinates, remove_last=False)
+    except Exception as err:
+      print('Error', err)
+      return None
diff --git a/city_model_structure/attributes/thermal_boundary.py b/city_model_structure/attributes/thermal_boundary.py
new file mode 100644
index 00000000..1d7d5dc8
--- /dev/null
+++ b/city_model_structure/attributes/thermal_boundary.py
@@ -0,0 +1,242 @@
+"""
+ThermalBoundary module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from typing import List
+
+from city_model_structure.attributes.layer import Layer
+from city_model_structure.attributes.thermal_opening import ThermalOpening
+from city_model_structure.attributes.thermal_zone import ThermalZone
+from helpers.configuration_helper import ConfigurationHelper
+
+
+class ThermalBoundary:
+  """
+  ThermalBoundary class
+  """
+  def __init__(self, surface, delimits):
+    self._surface = surface
+    self._delimits = delimits
+    # ToDo: up to at least LOD2 will be just one thermal opening per Thermal boundary, review for LOD3 and LOD4
+    self._thermal_openings = [ThermalOpening()]
+    self._layers = None
+    self._outside_solar_absorptance = ConfigurationHelper().outside_solar_absorptance
+    self._outside_thermal_absorptance = None
+    self._outside_visible_absorptance = None
+    self._window_ratio = None
+    self._u_value = None
+    self._window_area = None
+    self._shortwave_reflectance = 1 - self._outside_solar_absorptance
+
+  @property
+  def delimits(self) -> List[ThermalZone]:
+    """
+    Get the thermal zones delimited by the thermal boundary
+    :return: [ThermalZone]
+    """
+    return self._delimits
+
+  @property
+  def azimuth(self):
+    """
+    Thermal boundary azimuth in radians
+    :return: float
+    """
+    return self._surface.azimuth
+
+  @property
+  def inclination(self):
+    """
+    Thermal boundary inclination in radians
+    :return: float
+    """
+    return self._surface.inclination
+
+  @property
+  def area(self):
+    """
+    Thermal boundary area in square meters
+    :return: float
+    """
+    return self._surface.area
+
+  @property
+  def area_above_ground(self):
+    """
+    Thermal boundary area above ground in square meters
+    :return: float
+    """
+    return self._surface.area_above_ground
+
+  @property
+  def area_below_ground(self):
+    """
+    Thermal boundary area below ground in square meters
+    :return: float
+    """
+    return self._surface.area_below_ground
+
+  @property
+  def outside_solar_absorptance(self):
+    """
+    Get thermal boundary outside solar absorptance
+    :return: float
+    """
+    return self._outside_solar_absorptance
+
+  @outside_solar_absorptance.setter
+  def outside_solar_absorptance(self, value):
+    """
+    Set thermal boundary outside solar absorptance
+    :param value: float
+    :return: None
+    """
+    self._outside_solar_absorptance = value
+    self._shortwave_reflectance = 1.0 - float(value)
+
+  @property
+  def outside_thermal_absorptance(self):
+    """
+    Get thermal boundary outside thermal absorptance
+    :return: float
+    """
+    return self._outside_thermal_absorptance
+
+  @outside_thermal_absorptance.setter
+  def outside_thermal_absorptance(self, value):
+    """
+    Set thermal boundary outside thermal absorptance
+    :param value: float
+    :return: None
+    """
+    self._outside_thermal_absorptance = value
+
+  @property
+  def outside_visible_absorptance(self):
+    """
+    Get thermal boundary outside visible absorptance
+    :return: float
+    """
+    return self._outside_visible_absorptance
+
+  @outside_visible_absorptance.setter
+  def outside_visible_absorptance(self, value):
+    """
+    Set thermal boundary outside visible absorptance
+    :param value: float
+    :return: None
+    """
+    self._outside_visible_absorptance = value
+
+  @property
+  def thermal_openings(self) -> List[ThermalOpening]:
+    """
+    Get thermal boundary thermal openings
+    :return: [ThermalOpening]
+    """
+    return self._thermal_openings
+
+  @thermal_openings.setter
+  def thermal_openings(self, value):
+    """
+    Set thermal boundary thermal openings
+    :param value: [ThermalOpening]
+    :return: None
+    """
+    self._thermal_openings = value
+
+  @property
+  def layers(self) -> List[Layer]:
+    """
+    Get thermal boundary layers
+    :return: [Layers]
+    """
+    return self._layers
+
+  @layers.setter
+  def layers(self, value):
+    """
+    Set thermal boundary layers
+    :param value: [Layer]
+    :return: None
+    """
+    self._layers = value
+
+  @property
+  def type(self):
+    """
+    Thermal boundary surface type
+    :return: str
+    """
+    return self._surface.type
+
+  @property
+  def window_ratio(self):
+    """
+    Get thermal boundary window ratio
+    :return: float
+    """
+    return self._window_ratio
+
+  @window_ratio.setter
+  def window_ratio(self, value):
+    """
+    Set thermal boundary window ratio
+    :param value: float
+    :return: None
+    """
+    self._window_ratio = value
+
+  @property
+  def window_area(self):
+    """
+    Thermal boundary window area in square meters
+    :return: float
+    """
+    if self._window_area is None:
+      try:
+        self._window_area = float(self._surface.area) * float(self.window_ratio)
+      except TypeError:
+        raise Exception('Window ratio is not defined or invalid surface area')
+    return self._window_area
+
+  @property
+  def u_value(self):
+    """
+    Thermal boundary u value in W/m2K
+    internal and external convective coefficient in W/m2K values, can be configured at configuration.ini
+    :return: float
+    """
+    if self._u_value is None:
+      h_i = ConfigurationHelper().h_i
+      h_e = ConfigurationHelper().h_e
+      r_value = 1.0/h_i + 1.0/h_e
+      try:
+        for layer in self.layers:
+          if layer.material.no_mass:
+            r_value += float(layer.material.thermal_resistance)
+          else:
+            r_value = r_value + float(layer.material.conductivity) / float(layer.thickness)
+        self._u_value = 1.0/r_value
+      except TypeError:
+        raise Exception('Constructions layers are not initialized')
+    return self._u_value
+
+  @property
+  def shortwave_reflectance(self):
+    """
+    Get thermal boundary shortwave reflectance
+    :return: float
+    """
+    return self._shortwave_reflectance
+
+  @shortwave_reflectance.setter
+  def shortwave_reflectance(self, value):
+    """
+    Set thermal boundary shortwave reflectance
+    :param value: float
+    :return:
+    """
+    self._shortwave_reflectance = value
+    self._outside_solar_absorptance = 1.0 - float(value)
diff --git a/city_model_structure/attributes/thermal_opening.py b/city_model_structure/attributes/thermal_opening.py
new file mode 100644
index 00000000..3ed23816
--- /dev/null
+++ b/city_model_structure/attributes/thermal_opening.py
@@ -0,0 +1,171 @@
+"""
+ThermalOpening module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from helpers.configuration_helper import ConfigurationHelper
+
+
+class ThermalOpening:
+  """
+  ThermalOpening class
+  """
+  def __init__(self):
+    self._openable_ratio = None
+    self._conductivity = None
+    self._frame_ratio = ConfigurationHelper().frame_ratio
+    self._g_value = None
+    self._thickness = None
+    self._front_side_solar_transmittance_at_normal_incidence = None
+    self._back_side_solar_transmittance_at_normal_incidence = None
+    self._overall_u_value = None
+
+  @property
+  def openable_ratio(self):
+    """
+    Get thermal opening openable ratio, NOT IMPLEMENTED
+    :return: Exception
+    """
+    raise NotImplementedError()
+
+  @openable_ratio.setter
+  def openable_ratio(self, value):
+    """
+    Set thermal opening openable ratio, NOT IMPLEMENTED
+    :param value: Any
+    :return: Exception
+    """
+    raise NotImplementedError()
+
+  @property
+  def conductivity(self):
+    """
+    Get thermal opening conductivity in W/mK
+    :return: float
+    """
+    return self._conductivity
+
+  @conductivity.setter
+  def conductivity(self, value):
+    """
+    Get thermal opening conductivity in W/mK
+    :param value: float
+    :return: None
+    """
+    # The code to calculate overall_u_value is duplicated here and in thickness_m.
+    # This ensures a more robust code that returns the overall_u_value regardless the order the parameters are read.
+    self._conductivity = value
+    if self._overall_u_value is None and self.thickness is not None:
+      h_i = ConfigurationHelper().h_i
+      h_e = ConfigurationHelper().h_e
+      r_value = 1 / h_i + 1 / h_e + float(self.conductivity) / float(self.thickness)
+      self._overall_u_value = 1 / r_value
+
+  @property
+  def frame_ratio(self):
+    """
+    Get thermal opening frame ratio
+    :return: float
+    """
+    return self._frame_ratio
+
+  @frame_ratio.setter
+  def frame_ratio(self, value):
+    """
+    Set thermal opening frame ratio
+    :param value: float
+    :return: None
+    """
+    self._frame_ratio = value
+
+  @property
+  def g_value(self):
+    """
+    Get thermal opening g value
+    :return: float
+    """
+    return self._g_value
+
+  @g_value.setter
+  def g_value(self, value):
+    """
+    Set thermal opening g value
+    :param value:
+    :return:
+    """
+    self._g_value = value
+
+  @property
+  def thickness(self):
+    """
+    Get thermal opening thickness in meters
+    :return:
+    """
+    return self._thickness
+
+  @thickness.setter
+  def thickness(self, value):
+    """
+    Set thermal opening thickness in meters
+    :param value: float
+    :return: None
+    """
+    # The code to calculate overall_u_value is duplicated here and in conductivity.
+    # This ensures a more robust code that returns the overall_u_value regardless the order the parameters are read.
+    self._thickness = value
+    if self._overall_u_value is None and self.conductivity is not None:
+      h_i = ConfigurationHelper().h_i
+      h_e = ConfigurationHelper().h_e
+      r_value = 1 / h_i + 1 / h_e + float(self.conductivity) / float(self.thickness)
+      self._overall_u_value = 1 / r_value
+
+  @property
+  def front_side_solar_transmittance_at_normal_incidence(self):
+    """
+    Get thermal opening front side solar transmittance at normal incidence
+    :return: float
+    """
+    return self._front_side_solar_transmittance_at_normal_incidence
+
+  @front_side_solar_transmittance_at_normal_incidence.setter
+  def front_side_solar_transmittance_at_normal_incidence(self, value):
+    """
+    Set thermal opening front side solar transmittance at normal incidence
+    :param value: float
+    :return: None
+    """
+    self._front_side_solar_transmittance_at_normal_incidence = value
+
+  @property
+  def back_side_solar_transmittance_at_normal_incidence(self):
+    """
+    Get thermal opening back side solar transmittance at normal incidence
+    :return: float
+    """
+    return self._back_side_solar_transmittance_at_normal_incidence
+
+  @back_side_solar_transmittance_at_normal_incidence.setter
+  def back_side_solar_transmittance_at_normal_incidence(self, value):
+    """
+    Set thermal opening back side solar transmittance at normal incidence
+    :param value: float
+    :return: None
+    """
+    self._back_side_solar_transmittance_at_normal_incidence = value
+
+  @property
+  def overall_u_value(self):
+    """
+    Get thermal opening overall u value in W/m2K
+    :return: float
+    """
+    return self._overall_u_value
+
+  @overall_u_value.setter
+  def overall_u_value(self, value):
+    """
+    Get thermal opening overall u value in W/m2K
+    :param value: float
+    :return: None
+    """
+    self._overall_u_value = value
diff --git a/city_model_structure/attributes/thermal_zone.py b/city_model_structure/attributes/thermal_zone.py
new file mode 100644
index 00000000..f6eea62a
--- /dev/null
+++ b/city_model_structure/attributes/thermal_zone.py
@@ -0,0 +1,187 @@
+"""
+ThermalZone module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from typing import List, TypeVar
+
+from city_model_structure.attributes.surface import Surface
+from city_model_structure.attributes.usage_zone import UsageZone
+from helpers.configuration_helper import ConfigurationHelper
+
+ThermalBoundary = TypeVar('ThermalBoundary')
+
+
+class ThermalZone:
+  """
+  ThermalZone class
+  """
+  def __init__(self, surfaces):
+    self._surfaces = surfaces
+    self._floor_area = None
+    self._bounded = None
+    self._heated = ConfigurationHelper().heated
+    self._cooled = ConfigurationHelper().cooled
+    self._additional_thermal_bridge_u_value = ConfigurationHelper().additional_thermal_bridge_u_value
+    self._effective_thermal_capacity = None
+    self._indirectly_heated_area_ratio = ConfigurationHelper().indirectly_heated_area_ratio
+    self._infiltration_rate_system_on = ConfigurationHelper().infiltration_rate_system_on
+    self._infiltration_rate_system_off = None
+    self._usage_zones = None
+
+  @property
+  def heated(self):
+    """
+    Get thermal zone heated flag
+    :return: Boolean
+    """
+    return self._heated
+
+  @property
+  def cooled(self):
+    """
+    Get thermal zone cooled flag
+    :return: Boolean
+    """
+    return self._cooled
+
+  @property
+  def floor_area(self):
+    """
+    Get thermal zone floor area in square meters
+    :return: float
+    """
+    if self._floor_area is None:
+      self._floor_area = 0
+      for s in self._surfaces:
+        if s.type == 'Ground':
+          self._floor_area += s.area
+    return self._floor_area
+
+  @property
+  def bounded(self) -> List[ThermalBoundary]:
+    """
+    Get thermal boundaries bounding with the thermal zone
+    :return: [ThermalBoundary]
+    """
+    return self._bounded
+
+  @bounded.setter
+  def bounded(self, value):
+    """
+    Set thermal boundaries bounding with the thermal zone
+    :param value: [ThermalBoundary]
+    :return: None
+    """
+    self._bounded = value
+
+  @property
+  def surfaces(self) -> List[Surface]:
+    # todo: This property should be erased
+    """
+    Get thermal zone surfaces
+    :return: [Surface]
+    """
+    return self._surfaces
+
+  @property
+  def additional_thermal_bridge_u_value(self):
+    """
+    Get thermal zone additional thermal bridge u value W/m2K
+    :return: float
+    """
+    return self._additional_thermal_bridge_u_value
+
+  @additional_thermal_bridge_u_value.setter
+  def additional_thermal_bridge_u_value(self, value):
+    """
+    Set thermal zone additional thermal bridge u value W/m2K
+    :param value: float
+    :return: None
+    """
+    self._additional_thermal_bridge_u_value = value
+
+  @property
+  def effective_thermal_capacity(self):
+    """
+    Get thermal zone effective thermal capacity
+    :return: float
+    """
+    return self._effective_thermal_capacity
+
+  @effective_thermal_capacity.setter
+  def effective_thermal_capacity(self, value):
+    """
+    Set thermal zone effective thermal capacity
+    :param value: float
+    :return: None
+    """
+    self._effective_thermal_capacity = value
+
+  @property
+  def indirectly_heated_area_ratio(self):
+    """
+    Get thermal zone indirectly heated area ratio
+    :return: float
+    """
+    return self._indirectly_heated_area_ratio
+
+  @indirectly_heated_area_ratio.setter
+  def indirectly_heated_area_ratio(self, value):
+    """
+    Set thermal zone indirectly heated area ratio
+    :param value: float
+    :return: None
+    """
+    self._indirectly_heated_area_ratio = value
+
+  @property
+  def infiltration_rate_system_on(self):
+    """
+    Get thermal zone infiltration rate system on in air changes per hour
+    :return: float
+    """
+    return self._infiltration_rate_system_on
+
+  @infiltration_rate_system_on.setter
+  def infiltration_rate_system_on(self, value):
+    """
+    Set thermal zone infiltration rate system on in air changes per hour
+    :param value: float
+    :return: None
+    """
+    self._infiltration_rate_system_on = value
+
+  @property
+  def infiltration_rate_system_off(self):
+    """
+    Get thermal zone infiltration rate system off in air changes per hour
+    :return: float
+    """
+    return self._infiltration_rate_system_off
+
+  @infiltration_rate_system_off.setter
+  def infiltration_rate_system_off(self, value):
+    """
+    Set thermal zone infiltration rate system on in air changes per hour
+    :param value: float
+    :return: None
+    """
+    self._infiltration_rate_system_off = value
+
+  @property
+  def usage_zones(self) -> List[UsageZone]:
+    """
+    Get thermal zone usage zones
+    :return: [UsageZone]
+    """
+    return self._usage_zones
+
+  @usage_zones.setter
+  def usage_zones(self, values):
+    """
+    Set thermal zone usage zones
+    :param values: [UsageZone]
+    :return: None
+    """
+    self._usage_zones = values
diff --git a/city_model_structure/attributes/usage_zone.py b/city_model_structure/attributes/usage_zone.py
new file mode 100644
index 00000000..e82f9be0
--- /dev/null
+++ b/city_model_structure/attributes/usage_zone.py
@@ -0,0 +1,195 @@
+"""
+UsageZone module
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
+"""
+from typing import List
+
+from city_model_structure.attributes.internal_gains import InternalGains
+from helpers.configuration_helper import ConfigurationHelper
+
+
+class UsageZone:
+  """
+  UsageZone class
+  """
+  def __init__(self):
+    self._usage = None
+    self._internal_gains = None
+    self._heating_setpoint = None
+    self._heating_setback = None
+    self._cooling_setpoint = None
+    self._hours_day = None
+    self._days_year = None
+    # todo: this must come from library, talk to Rabeeh
+    self._mechanical_air_change = ConfigurationHelper().min_air_change
+    self._occupancy = None
+    self._schedules = None
+
+  @property
+  def internal_gains(self) -> List[InternalGains]:
+    """
+    Get usage zone internal gains
+    :return: [InternalGains]
+    """
+    return self._internal_gains
+
+  @internal_gains.setter
+  def internal_gains(self, value):
+    """
+    Set usage zone internal gains
+    :param value: [InternalGains]
+    :return: None
+    """
+    self._internal_gains = value
+
+  @property
+  def heating_setpoint(self):
+    """
+    Get usage zone heating set point in celsius grads
+    :return: float
+    """
+    return self._heating_setpoint
+
+  @heating_setpoint.setter
+  def heating_setpoint(self, value):
+    """
+    Set usage zone heating set point in celsius grads
+    :param value: float
+    :return: None
+    """
+    self._heating_setpoint = value
+
+  @property
+  def heating_setback(self):
+    """
+    Get usage zone heating setback in celsius grads
+    :return: float
+    """
+    return self._heating_setback
+
+  @heating_setback.setter
+  def heating_setback(self, value):
+    """
+    Set usage zone heating setback in celsius grads
+    :param value: float
+    :return: None
+    """
+    self._heating_setback = value
+
+  @property
+  def cooling_setpoint(self):
+    """
+    Get usage zone cooling setpoint in celsius grads
+    :return: float
+    """
+    return self._cooling_setpoint
+
+  @cooling_setpoint.setter
+  def cooling_setpoint(self, value):
+    """
+    Set usage zone cooling setpoint in celsius grads
+    :param value: float
+    :return: None
+    """
+    self._cooling_setpoint = value
+
+  @property
+  def hours_day(self):
+    """
+    Get usage zone usage hours per day
+    :return: float
+    """
+    return self._hours_day
+
+  @hours_day.setter
+  def hours_day(self, value):
+    """
+    Set usage zone usage hours per day
+    :param value: float
+    :return: float
+    """
+    self._hours_day = value
+
+  @property
+  def days_year(self):
+    """
+    Get usage zone usage days per year
+    :return: float
+    """
+    return self._days_year
+
+  @days_year.setter
+  def days_year(self, value):
+    """
+    Set usage zone usage days per year
+    :param value: float
+    :return: None
+    """
+    self._days_year = value
+
+  @property
+  def mechanical_air_change(self):
+    """
+    Set usage zone mechanical air change in air change per hour
+    :return: float
+    """
+    return self._mechanical_air_change
+
+  @mechanical_air_change.setter
+  def mechanical_air_change(self, value):
+    """
+    Get usage zone mechanical air change in air change per hour
+    :param value: float
+    :return: None
+    """
+    self._mechanical_air_change = value
+
+  @property
+  def usage(self):
+    """
+    Get usage zone usage
+    :return: str
+    """
+    return self._usage
+
+  @usage.setter
+  def usage(self, value):
+    """
+    Get usage zone usage
+    :param value: str
+    :return: None
+    """
+    self._usage = value
+
+  @property
+  def occupancy(self):
+    """
+    Get occupancy data
+    :return: [Occupancy]
+    """
+    return self._occupancy
+
+  @occupancy.setter
+  def occupancy(self, values):
+    """
+    Set occupancy
+    :param values: [Occupancy]
+    """
+    self._occupancy = values
+
+  @property
+  def schedules(self):
+    """
+    Get schedule of Sundays
+    :return: [Sundays Schedule_Values]
+    """
+    return self._schedules
+
+  @schedules.setter
+  def schedules(self, value):
+    """
+    occupancy schedules of Sundays
+    :param value: Sunday schedules
+    """
+    self._schedules = value
diff --git a/factories/weather/weather_factory.py b/factories/weather/weather_factory.py
new file mode 100644
index 00000000..2e89266d
--- /dev/null
+++ b/factories/weather/weather_factory.py
@@ -0,0 +1,37 @@
+"""
+WeatherFactory retrieve the specific weather module for the given source format
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Pilar Monsalvete pilar_monsalvete@yahoo.es
+"""
+
+from factories.weather.weather_feeders.cli_weather_parameters import CliWeatherParameters
+from factories.weather.weather_feeders.dat_weather_parameters import DatWeatherParameters
+
+
+class WeatherFactory:
+  """
+  WeatherFactory class
+  """
+
+  # todo: modify full_path_weather to make it depending on "city"
+  def __init__(self, handler, city, full_path_weather):
+    self._handler = '_' + handler.lower().replace(' ', '_')
+    self._city = city
+    self._full_path_weather = full_path_weather
+    self.factory()
+
+  def _cli(self):
+    CliWeatherParameters(self._full_path_weather)
+
+  def _dat(self):
+    DatWeatherParameters(self._full_path_weather)
+
+  def _tmy(self):
+    raise Exception('Not implemented')
+
+  def factory(self):
+    """
+    Enrich the city with the usage information
+    :return: None
+    """
+    getattr(self, self._handler, lambda: None)()
diff --git a/factories/weather/weather_feeders/cli_weather_parameters.py b/factories/weather/weather_feeders/cli_weather_parameters.py
new file mode 100644
index 00000000..aabfb4ab
--- /dev/null
+++ b/factories/weather/weather_feeders/cli_weather_parameters.py
@@ -0,0 +1,13 @@
+"""
+CliWeatherParameters class to extract weather parameters from a defined region in .cli format
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Pilar Monsalvete pilar_monsalvete@yahoo.es
+"""
+
+
+class CliWeatherParameters:
+  """
+  CliWeatherParameters class
+  """
+  def __init__(self, full_path_weather):
+    self._full_path_weather = full_path_weather
diff --git a/factories/weather/weather_feeders/dat_weather_parameters.py b/factories/weather/weather_feeders/dat_weather_parameters.py
new file mode 100644
index 00000000..5145f524
--- /dev/null
+++ b/factories/weather/weather_feeders/dat_weather_parameters.py
@@ -0,0 +1,24 @@
+"""
+CliWeatherParameters class to extract weather parameters from a defined region in .dat format
+SPDX - License - Identifier: LGPL - 3.0 - or -later
+Copyright © 2020 Project Author Pilar Monsalvete pilar_monsalvete@yahoo.es
+"""
+
+import pandas as pd
+
+
+class DatWeatherParameters:
+  """
+  DatWeatherParameters class
+  """
+  def __init__(self, full_path_weather):
+    self._full_path_weather = full_path_weather
+    self._weather_values = None
+
+  def weather_values(self):
+    if self._full_path_weather is not None:
+      # TODO: catch error if file does not exist
+      if self._weather_values is None:
+        self._weather_values = pd.read_csv(self._full_path_weather, sep='\s+', header=None,
+                                           names=['hour', 'global_horiz', 'temperature', 'diffuse', 'beam', 'empty'])
+    return self._weather_values
diff --git a/factories/weather/weather_feeders/helpers/weather.py b/factories/weather/weather_feeders/helpers/weather.py
new file mode 100644
index 00000000..b8cadb17
--- /dev/null
+++ b/factories/weather/weather_feeders/helpers/weather.py
@@ -0,0 +1,31 @@
+import math
+import pandas as pd
+import helpers.constants as cte
+from helpers import monthly_values as mv
+
+
+class Weather(object):
+  def __init__(self, weather_values):
+    self._weather_values = pd.concat([mv.MonthlyValues().month_hour, weather_values], axis=1)
+    self._temperatures_hourly = None
+
+  @property
+  def external_and_sky_temperatures(self):
+    if self._temperatures_hourly is None:
+      self._temperatures_hourly = self._weather_values[['month', 'temperature']]
+      sky_temperature = self.sky_temperature(self._temperatures_hourly)
+      self._temperatures_hourly = pd.concat([self._temperatures_hourly, sky_temperature], axis=1)
+    return self._temperatures_hourly
+
+  @staticmethod
+  def sky_temperature(ambient_temperature):
+    # Swinbank - Fuentes sky model approximation(1963) based on cloudiness statistics(32 %) in United States
+    # ambient temperatures( in °C)
+    # sky temperatures( in °C)
+    _ambient_temperature = ambient_temperature[['temperature']].to_numpy()
+    values = []
+    for temperature in _ambient_temperature:
+      value = 0.037536 * math.pow((temperature + cte.celsius_to_kelvin), 1.5) \
+              + 0.32 * (temperature + cte.celsius_to_kelvin) - cte.celsius_to_kelvin
+      values.append(value)
+    return pd.DataFrame(values, columns=['sky temperature'])