diff --git a/main.py b/main.py
new file mode 100644
index 0000000..af831a7
--- /dev/null
+++ b/main.py
@@ -0,0 +1,102 @@
+from coefficients import THERMAL_CONDUCTIVITY_HIGH as thermals
+from coefficients import RSI_HORIZONTAL, RSI_DOWNWARD, RSE, RSI_UPWARD
+from interfaces import LayeredSurface, FixedUSurface, MaterialLayer
+from ventilation import Room, RoomKind
+from report import report
+import sys
+
+if len(sys.argv) < 2:
+    situation = "now"
+else:
+    situation = sys.argv[1]
+
+# FIXME: Values are a bit coarse, but should be reasonably close to reality
+protected_volume = 480
+exterior_wall_area = 110
+window_area = 43
+floor_area = 63
+roof_area = 73
+area = exterior_wall_area + window_area + floor_area + roof_area
+average_window_u = 1.19
+
+rooms = [
+    Room(RoomKind.OPEN_KITCHEN, 3.7 * 3),
+    Room(RoomKind.TOILET, 0.9 * 1.5),
+    Room(RoomKind.OTHER_WET, 1.8 * 3.0),  # washing/storage room
+    Room(RoomKind.OTHER_WET, 3.5 * 1.9),  # bathroom
+    Room(RoomKind.LIVING_ROOM, 9 * 3.75),
+    Room(RoomKind.OTHER_DRY, 9 * 3.75 / 2),  # big room 1
+    Room(RoomKind.OTHER_DRY, 9 * 3.75 / 2),  # big room 2
+    Room(RoomKind.OTHER_DRY, 3.3 * 3),  # small room
+]
+
+floor_layers = [
+    MaterialLayer(thermals["pur"], 0.12),
+    MaterialLayer(thermals["concrete"], 0.20),
+]
+
+roof_layers = [
+    MaterialLayer(thermals["particle_board"], 0.01),
+    MaterialLayer(thermals["mineral_wool"], 0.12),
+    MaterialLayer(thermals["pir"], 0.06),
+]
+
+if situation == "now":
+    wall_layers = [
+        MaterialLayer(thermals["brick"], 0.11),
+        MaterialLayer(thermals["mineral_wool"], 0.06),
+        MaterialLayer(thermals["brick"], 0.11),
+    ]
+    lump_sum_thermal_bridge = 0.20  # W/m^2K
+    situation_dict = {
+        "name": "now",
+        "ventilation_rooms": [],  # no active ventilation yet
+        "ventilation_eta": 1.0,
+        "ventilation_v50_area": area,
+        "ventilation_v50_value": 4.0,  # maybe 6.0
+        "transmission_interfaces": [
+            LayeredSurface(
+                "exterior wall", exterior_wall_area, wall_layers, RSI_HORIZONTAL, RSE
+            ),
+            LayeredSurface(
+                "floor", floor_area, floor_layers, RSI_DOWNWARD, RSI_DOWNWARD, b=0.8
+            ),
+            LayeredSurface("roof", roof_area, roof_layers, RSI_UPWARD, RSE),
+            FixedUSurface("windows/doors", window_area, average_window_u),
+            FixedUSurface("thermal bridge", area, lump_sum_thermal_bridge),
+        ],
+        "environment_delta_t_worst": 20 - -8,
+        "environment_delta_t_typical": 20 - 4,
+    }
+elif situation == "future":
+    wall_layers = [
+        MaterialLayer(thermals["brick"], 0.11),
+        MaterialLayer(thermals["mineral_wool"], 0.06),
+        MaterialLayer(thermals["brick"], 0.11),
+        MaterialLayer(thermals["pur"], 0.12),
+    ]
+    lump_sum_thermal_bridge = 0.10  # W/m^2K
+    situation_dict = {
+        "name": "future",
+        "ventilation_rooms": rooms,
+        "ventilation_eta": 0.85,
+        "ventilation_v50_area": area,
+        "ventilation_v50_value": 2.0,
+        "transmission_interfaces": [
+            LayeredSurface(
+                "exterior wall", exterior_wall_area, wall_layers, RSI_HORIZONTAL, RSE
+            ),
+            LayeredSurface(
+                "floor", floor_area, floor_layers, RSI_DOWNWARD, RSI_DOWNWARD, b=0.8
+            ),
+            LayeredSurface("roof", roof_area, roof_layers, RSI_UPWARD, RSE),
+            FixedUSurface("windows/doors", window_area, average_window_u),
+            FixedUSurface("thermal bridge", area, lump_sum_thermal_bridge),
+        ],
+        "environment_delta_t_worst": 20 - -8,
+        "environment_delta_t_typical": 20 - 4,
+    }
+else:
+    raise ValueError("wrong situation")
+
+report(situation_dict)