diff --git a/config.default.yaml b/config.default.yaml
index fa3eadab..247e7682 100644
--- a/config.default.yaml
+++ b/config.default.yaml
@@ -119,19 +119,25 @@ sector:
   'time_dep_hp_cop' : True #time dependent heat pump coefficient of performance
   'heat_pump_sink_T' : 55. # Celsius, based on DTU / large area radiators; used in build_cop_profiles.py
    # conservatively high to cover hot water and space heating in poorly-insulated buildings
-  'retrofitting' :
-    'retro_exogen': True # space heat demand savings exogenously
-    'dE': # reduction of space heat demand (applied before losses in DH)
-      2020 : 0.
-      2030 : 0.15
-      2040 : 0.3
-      2050 : 0.4
+  'vary_space_heat_exogenously': True  # reduces or increases space heat demand by a given factor (applied before losses in DH)
+  # this can represent e.g. increasing floor area, increased thermal comfort,
+  # population grow, climate change, building demolition, building  renovation
+  'vary_space_heat_exogenously_factor':
+  # the factor are determined by the LTS scenario from http://tool.european-calculator.eu/app/buildings/building-types-area/?levers=1ddd4444421213bdbbbddd44444ffffff11f411111221111211l212221
+          2020:    0.10  # this results in a space heat demand reduction of 10%
+          2025:    0.09  # first heat demand increases compared to 2020 because of larger floor area per capita
+          2030:    0.09
+          2035:    0.11
+          2040:    0.16
+          2045:    0.21
+          2050:    0.29
+  'retrofitting' :  # co-optimises building renovation to reduce space heat demand
     'retro_endogen': False  # co-optimise space heat savings
-    'cost_factor' : 1.0
+    'cost_factor' : 1.0   # weight costs for building renovation
     'interest_rate': 0.04  # for investment in building components
     'annualise_cost': True  # annualise the investment costs
     'tax_weighting': False   # weight costs depending on taxes in countries
-    'construction_index': True   # weight costs depending on labour/material costs per ct
+    'construction_index': True   # weight costs depending on labour/material costs per country
   'tes' : True
   'tes_tau' : 3.
   'boilers' : True
diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index f263626f..1553c4db 100644
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -1179,11 +1179,10 @@ def add_heat(network):
 
     urban_fraction = options['central_fraction']*pop_layout["urban"]/(pop_layout[["urban","rural"]].sum(axis=1))
 
-    # building retrofitting, exogenously reduce space heat demand
-    if options["retrofitting"]["retro_exogen"]:
-        dE = get_parameter(options["retrofitting"]["dE"])
-        print("retrofitting exogenously, assumed space heat reduction of ",
-              dE)
+    # exogenously reduce space heat demand
+    if options["vary_space_heat_exogenously"]:
+        dE = get_parameter(options["vary_space_heat_exogenously_factor"])
+        print("assumed space heat reduction of {} %".format(dE*100))
         for sector in sectors:
             heat_demand[sector + " space"] = (1-dE)*heat_demand[sector + " space"]
 
@@ -1914,7 +1913,7 @@ if __name__ == "__main__":
                         floor_area = "resources/floor_area_{network}_s{simpl}_{clusters}.csv"
             ),
             output=['results/version-cb48be3/prenetworks/{network}_s{simpl}_{clusters}_lv{lv}__{sector_opts}_{planning_horizons}.nc']
-    
+
         )
         import yaml
         with open('config.yaml', encoding='utf8') as f: