diff --git a/backend/onboarders/epc_descriptions.py b/backend/onboarders/epc_descriptions.py
index 36e9a4f8..e9b770fd 100644
--- a/backend/onboarders/epc_descriptions.py
+++ b/backend/onboarders/epc_descriptions.py
@@ -368,7 +368,34 @@ def flat_limited_insulation_efficiency(age_band: EpcConstructionAgeBand) -> EpcE
     pass
 
 
-def flat_insulated_efficiency(age_band: EpcConstructionAgeBand) -> EpcEfficiency:
+def flat_insulated_efficiency_age_band(age_band: EpcConstructionAgeBand) -> EpcEfficiency:
+    """
+    before 1900, 1900-1929, 1930-1949, 1950-1966, 1967-1975  -> Pitched, no insulation, Very Poor
+    1976-1982 -> Pitched, limited insulation, Poor
+    1983-1990, to 1996-2002 Pitched, insulated, Average
+    2003 - 2006, 2012-2022 -> Pitched, insulated, Good
+    2023 onwards -> Pitched, insulated, Very Good
+    :param age_band: EpcConstructionAgeBand
+    :return: EpcEfficiency
+    """
+
+    start_year = age_band.start_year()
+    if start_year >= 2023:
+        return EpcEfficiency.VERY_GOOD
+
+    if start_year >= 2003:
+        return EpcEfficiency.GOOD
+
+    if start_year >= 1983:
+        return EpcEfficiency.AVERAGE
+
+    if start_year >= 1976:
+        return EpcEfficiency.POOR
+
+    return EpcEfficiency.VERY_POOR
+
+
+def flat_insulated_efficiency_thickness(insulation_thickness: int | None) -> EpcEfficiency:
     pass
 
 
@@ -453,4 +480,10 @@ ROOF_DESCRIPTION_EFFICIENCIES: Mapping[EpcRoofDescriptions, RoofEfficiencyRule]
     # function mappings
     EpcRoofDescriptions.pitched_insulated_assumed: loft_insulated_efficiency,
 
+    # Loft af rafters
+    EpcRoofDescriptions.loft_insulated_at_rafters: loft_insulated_at_rafters_efficiency,
+
+    # Another dwelling above
+    EpcRoofDescriptions.another_dwelling_above: EpcEfficiency.NA,
+
 }