diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index fa72cfe5..0e5dc569 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -1560,6 +1560,7 @@ def _map_sap_heating(
         ],
         has_fixed_air_conditioning=ventilation.has_fixed_air_conditioning,
         secondary_fuel_type=secondary_fuel_type,
+        secondary_heating_type=heating.secondary_heating.secondary_system,
         shower_outlets=shower_outlets,
         cylinder_size=heating.water_heating.cylinder_size if heating.water_heating.cylinder_size != "No Cylinder" else None,
         cylinder_insulation_thickness_mm=heating.water_heating.insulation_thickness_mm,