diff --git a/hub/city_model_structure/building_demand/surface.py b/hub/city_model_structure/building_demand/surface.py
index 2cd42755..ab27ffe8 100644
--- a/hub/city_model_structure/building_demand/surface.py
+++ b/hub/city_model_structure/building_demand/surface.py
@@ -42,7 +42,7 @@ class Surface:
     self._short_wave_reflectance = None
     self._long_wave_emittance = None
     self._inverse = None
-    self._associated_thermal_boundaries = []
+    self._associated_thermal_boundaries = None
     self._vegetation = None
     self._percentage_shared = None
     self._solar_collectors_area_reduction_factor = None
diff --git a/hub/imports/construction_factory.py b/hub/imports/construction_factory.py
index 38019b66..dcf8b054 100644
--- a/hub/imports/construction_factory.py
+++ b/hub/imports/construction_factory.py
@@ -54,3 +54,5 @@ class ConstructionFactory:
     :return: None
     """
     getattr(self, self._handler, lambda: None)()
+    for building in self._city.buildings:
+      _ = building.thermal_zones_from_internal_zones  # ensure internal zones initialization
diff --git a/tests/test_exports.py b/tests/test_exports.py
index 8f5204a9..ab3943f7 100644
--- a/tests/test_exports.py
+++ b/tests/test_exports.py
@@ -144,6 +144,6 @@ class TestExports(TestCase):
     UsageFactory('nrcan', city).enrich()
     WeatherFactory('epw', city).enrich()
     try:
-      EnergyBuildingsExportsFactory('idf', city, self._output_path).export()
+      EnergyBuildingsExportsFactory('idf', city, self._output_path, target_buildings=[1]).export()
     except Exception:
       self.fail("Idf ExportsFactory raised ExceptionType unexpectedly!")
diff --git a/tests/test_geometry_factory.py b/tests/test_geometry_factory.py
index 3b5bd8f8..d436851c 100644
--- a/tests/test_geometry_factory.py
+++ b/tests/test_geometry_factory.py
@@ -93,7 +93,7 @@ class TestGeometryFactory(TestCase):
       self.assertIsNone(surface.short_wave_reflectance, 'surface short_wave_reflectance is not none')
       self.assertIsNone(surface.long_wave_emittance, 'surface long_wave_emittance is not none')
       self.assertIsNotNone(surface.inverse, 'surface inverse is none')
-      self.assertEqual(len(surface.associated_thermal_boundaries), 0, 'associated_thermal_boundaries are assigned')
+      self.assertIsNone(surface.associated_thermal_boundaries, 'associated_thermal_boundaries are assigned')
       self.assertIsNone(surface.vegetation, 'surface vegetation is not none')
 
   # citygml_classes