diff --git a/city_model_structure/attributes/polygon.py b/city_model_structure/attributes/polygon.py
index 7705a575..dcfa5dd7 100644
--- a/city_model_structure/attributes/polygon.py
+++ b/city_model_structure/attributes/polygon.py
@@ -19,42 +19,19 @@ class Polygon:
   Polygon class
   """
 
-#  def __init__(self, points):
   def __init__(self, coordinates):
 
     self._area = None
-#    self._points = points
     self._points = None
     self._points_list = None
     self._normal = None
     self._inverse = None
     self._edges = None
-#    self._coordinates = None
     self._coordinates = coordinates
     self._triangles = None
     self._vertices = None
     self._faces = None
 
-#  @property
-#  def points(self) -> List[Point]:
-#    """
-#    List of points belonging to the polygon [[x, y, z],...]
-#    :return: List[Point]
-#    """
-#    return self._points
-#
-#  @property
-#  def coordinates(self) -> List[np.ndarray]:
-#    """
-#    List of points in the shape of its coordinates belonging to the polygon [[x, y, z],...]
-#    :return: np.array
-#    """
-#    if self._coordinates is None:
-#      self._coordinates = []
-#      for point in self.points:
-#        self._coordinates.append(np.array(point.coordinates))
-#    return self._coordinates
-#
   @property
   def points(self) -> List[Point]:
     """
diff --git a/exports/formats/idf.py b/exports/formats/idf.py
index 335d453c..988905a3 100644
--- a/exports/formats/idf.py
+++ b/exports/formats/idf.py
@@ -127,6 +127,7 @@ class Idf:
     for construction in self._idf.idfobjects[self._CONSTRUCTION]:
       if construction.Name == thermal_boundary.construction_name:
         return
+
     if thermal_boundary.layers is None:
       for material in self._idf.idfobjects[self._MATERIAL]:
         if material.Name == "DefaultMaterial":
@@ -153,7 +154,7 @@ class Idf:
   def _add_thermostat(self, usage_zone):
     thermostat_name = f'Thermostat {usage_zone.usage}'
     for thermostat in self._idf.idfobjects[self._THERMOSTAT]:
-      if thermostat == thermostat_name:
+      if thermostat.Name == thermostat_name:
         return thermostat
     return self._idf.newidfobject(self._THERMOSTAT,
                                   Name=thermostat_name,
@@ -161,6 +162,9 @@ class Idf:
                                   Constant_Cooling_Setpoint=usage_zone.cooling_setpoint)
 
   def _add_heating_system(self, usage_zone):
+    for air_system in self._idf.idfobjects[self._IDEAL_LOAD_AIR_SYSTEM]:
+      if air_system.Zone_Name == usage_zone.id:
+        return
     thermostat = self._add_thermostat(usage_zone)
     # todo: doesn't the air system have name?
     self._idf.newidfobject(self._IDEAL_LOAD_AIR_SYSTEM,
@@ -248,6 +252,6 @@ class Idf:
           surface = self._idf.newidfobject(self._SURFACE, Name=f'{boundary.surface.name}',
                                            Surface_Type=idf_surface, Zone_Name=usage_zone.id,
                                            Construction_Name=boundary.construction_name)
-          coordinates = self._matrix_to_list(boundary.surface.coordinates)
+          coordinates = self._matrix_to_list(boundary.surface.solid_polygon.coordinates)
           surface.setcoords(coordinates)
           self._idf.intersect_match()
diff --git a/imports/construction/us_physics_parameters.py b/imports/construction/us_physics_parameters.py
index ea6d7bf8..2ef2d344 100644
--- a/imports/construction/us_physics_parameters.py
+++ b/imports/construction/us_physics_parameters.py
@@ -68,6 +68,7 @@ class UsPhysicsParameters(NrelPhysicsInterface):
         thermal_boundary.outside_visible_absorptance = thermal_boundary_archetype.outside_visible_absorptance
         thermal_boundary.construction_name = thermal_boundary_archetype.construction_name
         thermal_boundary.window_ratio = thermal_boundary_archetype.window_ratio
+        thermal_boundary.layers = []
         for layer_archetype in thermal_boundary_archetype.layers:
           layer = Layer()
           layer.thickness = layer_archetype.thickness
@@ -82,6 +83,7 @@ class UsPhysicsParameters(NrelPhysicsInterface):
           material.visible_absorptance = layer_archetype.visible_absorptance
           material.thermal_resistance = layer_archetype.thermal_resistance
           layer.material = material
+          thermal_boundary.layers.append(layer)
         for thermal_opening in thermal_boundary.thermal_openings:
           if thermal_boundary_archetype.thermal_opening is not None:
             thermal_opening_archetype = thermal_boundary_archetype.thermal_opening
diff --git a/imports/construction_factory.py b/imports/construction_factory.py
index 186710ad..e68dc4a9 100644
--- a/imports/construction_factory.py
+++ b/imports/construction_factory.py
@@ -38,4 +38,4 @@ class ConstructionFactory:
     Enrich the city with the construction information
     :return: None
     """
-    self._nrcan()
+    self._nrel()
diff --git a/imports/usage_factory.py b/imports/usage_factory.py
index 9b604ded..ce943098 100644
--- a/imports/usage_factory.py
+++ b/imports/usage_factory.py
@@ -7,6 +7,8 @@ from pathlib import Path
 from imports.usage.hft_usage_parameters import HftUsageParameters
 from imports.usage.ca_usage_parameters import CaUsageParameters
 
+# todo: handle missing lambda and rise error.
+
 
 class UsageFactory:
   """