diff --git a/hub/exports/building_energy/trnsys.py b/hub/exports/building_energy/trnsys.py
index bd54972c..86aa66d9 100644
--- a/hub/exports/building_energy/trnsys.py
+++ b/hub/exports/building_energy/trnsys.py
@@ -168,7 +168,7 @@ class Trnsys:
           Trnsys._add_schedule(f, schedule, 'SCHEDULE LIGHTING ')
 
   @staticmethod
-  def _construction(f, building):
+  def _constructions(f, building):
     f.write('***************************************\n')
     f.write(f'* Construction\n')
     f.write('***************************************\n')
@@ -190,13 +190,116 @@ class Trnsys:
           constructions[thermal_boundary.construction_name]['thickness'] = f'{constructions[thermal_boundary.construction_name]["thickness"]} {layer.thickness} '
     for name, values in constructions.items():
       f.write(f'CONSTRUCTION {name.replace(" ", "_").upper()}\n')
-      f.write(f'LAYERS = {constructions[thermal_boundary.construction_name]["layers"]}\n')
-      f.write(f'THICKNESS = {constructions[thermal_boundary.construction_name]["thickness"]}\n')
-      f.write(f'ABS-FRONT = {constructions[thermal_boundary.construction_name]["absortance-front"]} : ABS-BACK = {constructions[thermal_boundary.construction_name]["absortance-back"]}\n')
-      f.write(f'EPS-FRONT = {constructions[thermal_boundary.construction_name]["resistance-front"]} : EPS-BACK = {constructions[thermal_boundary.construction_name]["resistance-back"]}\n')
-      f.write(f'HFRONT = {constructions[thermal_boundary.construction_name]["he"]} : HBACK = {constructions[thermal_boundary.construction_name]["hi"]}\n')
+      f.write(f'LAYERS = {values["layers"]}\n')
+      f.write(f'THICKNESS = {values["thickness"]}\n')
+      f.write(f'ABS-FRONT = {values["absortance-front"]} : ABS-BACK = {values["absortance-back"]}\n')
+      f.write(f'EPS-FRONT = {values["resistance-front"]} : EPS-BACK = {values["resistance-back"]}\n')
+      f.write(f'HFRONT = {values["he"]} : HBACK = {values["hi"]}\n')
       f.write('\n')
 
+  @staticmethod
+  def _windows(f, building):
+    f.write('***************************************\n')
+    f.write(f'* Windows\n')
+    f.write('***************************************\n')
+    windows = {}
+    for thermal_zone in building.thermal_zones_from_internal_zones:
+      for thermal_boundary in thermal_zone.thermal_boundaries:
+        polygon = thermal_boundary.parent_surface.solid_polygon
+        min_z = math.inf
+        max_z = -math.inf
+        Z = 2
+        for point in polygon.points:
+          min_z = min(min_z, point.coordinates[Z])
+          max_z = max(max_z, point.coordinates[Z])
+        height = max_z - min_z
+        if height == 0:
+          height = 1
+
+        for opening_id, thermal_opening in enumerate(thermal_boundary.thermal_openings):
+          absortance = 0.6
+          if thermal_opening.conductivity is not None:
+            absortance = 1 - thermal_opening.conductivity
+          windows[f'{thermal_opening.construction_name}'] = {
+            'window_id': opening_id,
+            'hi': thermal_opening.hi,
+            'he': thermal_opening.he,
+            'slope': -999,
+            'space_id': 3,
+            'width': thermal_opening.area / height,  # todo: this is just an estimation as the surfaces may not be squares.
+            'height':  height,
+            'frame_f': 0,
+            'frame_u': thermal_opening.overall_u_value,
+            'abs_frame': absortance,
+            'ri_shade': 0,
+            're_shade': 0,
+            're_fli_shade': 0.5,
+            're_flo_shade': 0.5,
+            'cci_shade': 0.5,
+            'eps_frame': 0.9,
+            'epsi_shade': 0.9,
+            'it_shade_close': 0,
+            'it_shade_open': 0,
+            'flow_to_air_node': 1,
+            'pert': 0,
+            'penrt': 0,
+            'rad_material': 'undefined',
+            'rad_material_shd1': 'undefined'
+          }
+    for name, values in windows.items():
+      f.write(f'WINDOW {name.replace(" ", "_").upper()}\n')
+      f.write(f' WINID={values["window_id"]} :')
+      f.write(f' HINSIDE={values["hi"]} :')
+      f.write(f' HOUTSIDE={values["he"]} :')
+      f.write(f' SLOPE={values["slope"]} :')
+      f.write(f' SPACID={values["space_id"]} :')
+      f.write(f' WWID={values["width"]} :')
+      f.write(f' WHEIG={values["height"]} :')
+      f.write(f' FFRAME={values["frame_f"]} :')
+      f.write(f' UFRAME={values["frame_u"]} :')
+      f.write(f' ABSFRAME={values["abs_frame"]} :')
+      f.write(f' RISHADE={values["ri_shade"]} :')
+      f.write(f' RESHADE={values["re_shade"]} :')
+      f.write(f' REFLISHADE={values["re_fli_shade"]} :')
+      f.write(f' REFLOSHADE={values["re_flo_shade"]} :')
+      f.write(f' CCISHADE={values["cci_shade"]} :')
+      f.write(f' EPSFRAME={values["eps_frame"]} :')
+      f.write(f' EPSIFRAME={values["epsi_shade"]} :')
+      f.write(f' ITSHADECLOSE={values["it_shade_close"]} :')
+      f.write(f' ITSHADEOPEN={values["it_shade_open"]} :')
+      f.write(f' FLOWTOAIRNODE={values["flow_to_air_node"]} :')
+      f.write(f' PERT={values["pert"]} :')
+      f.write(f' PENRT={values["penrt"]} :')
+      f.write(f' RADMATERIAL={values["rad_material"]} :')
+      f.write(f' RADMATERIAL_SHD1={values["rad_material_shd1"]}\n')
+
+  @staticmethod
+  def _empty_sections(f):
+    f.write('***************************************\n')
+    f.write(f'*  Gains / Losses\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Confort\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Infiltration\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Ventilation\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Cooling\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Heating\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Daylight control\n')
+    f.write('***************************************\n')
+    f.write('***************************************\n')
+    f.write(f'*  Confort\n')
+    f.write('***************************************\n')
+
   def export(self):
     for building in self._buildings:
       path = Path(self._path / f'{building.name}.b18')
@@ -207,6 +310,8 @@ class Trnsys:
         Trnsys._types(f, building)
         Trnsys._inputs(f)
         Trnsys._schedules(f, building)
-        Trnsys._construction(f, building)
+        Trnsys._constructions(f, building)
+        Trnsys._windows(f, building)
+        Trnsys._empty_sections(f)
 
 
diff --git a/tests/test_exports.py b/tests/test_exports.py
index c851bc67..b6228779 100644
--- a/tests/test_exports.py
+++ b/tests/test_exports.py
@@ -165,4 +165,4 @@ class TestExports(TestCase):
     ConstructionFactory('nrcan', city).enrich()
     UsageFactory('nrcan', city).enrich()
     WeatherFactory('epw', city).enrich()
-    EnergyBuildingsExportsFactory('trnsys', city, self._output_path).export()
\ No newline at end of file
+    EnergyBuildingsExportsFactory('trnsys', city, self._output_path).export()