diff --git a/hub/city_model_structure/building.py b/hub/city_model_structure/building.py
index 754e7b60..9b085a2a 100644
--- a/hub/city_model_structure/building.py
+++ b/hub/city_model_structure/building.py
@@ -393,7 +393,7 @@ class Building(CityObject):
     """
     results = {}
     peak_lighting = 0
-    for thermal_zone in self.thermal_zones:
+    for thermal_zone in self.thermal_zones_from_internal_zones:
       lighting = thermal_zone.lighting
       for schedule in lighting.schedules:
         peak = max(schedule.values) * lighting.density * thermal_zone.total_floor_area
@@ -411,7 +411,7 @@ class Building(CityObject):
     """
     results = {}
     peak_appliances = 0
-    for thermal_zone in self.thermal_zones:
+    for thermal_zone in self.thermal_zones_from_internal_zones:
       appliances = thermal_zone.appliances
       for schedule in appliances.schedules:
         peak = max(schedule.values) * appliances.density * thermal_zone.total_floor_area