diff --git a/backend/engine/engine.py b/backend/engine/engine.py
index 3014f2b3..65393e20 100644
--- a/backend/engine/engine.py
+++ b/backend/engine/engine.py
@@ -134,7 +134,7 @@ def extract_portfolio_aggregation_data(
             lower_bound_valuation_uplift, upper_bound_valuation_uplift = 0, 0
 
         agg_data.append({
-            "pre_retrofit_epc": p.data["current-energy-rating"],
+            "pre_retrofit_epc": p.epc_record.current_energy_rating,
             "post_retrofit_epc": new_epc_bands[p.id],
             "pre_retrofit_co2": pre_retrofit_co2,
             "post_retrofit_co2": post_retrofit_co2,
@@ -1145,7 +1145,7 @@ async def model_engine(body: PlanTriggerRequest):
                 optimiser.solve()
                 solution = optimiser.solution
                 gain = optimiser.solution_gain
-                post_sap = int(p.data["current-energy-efficiency"]) + gain
+                post_sap = p.epc_record.current_energy_efficiency + gain
 
                 pv_size = next(
                     (m["array_size"] for m in solution if m["type"] == "solar_pv"), 0
@@ -1242,7 +1242,7 @@ async def model_engine(body: PlanTriggerRequest):
 
             # This will include everything, including already installed
             total_sap_points = sum([r["sap_points"] for r in default_recommendations])
-            new_sap_points = float(p.data["current-energy-efficiency"]) + total_sap_points
+            new_sap_points = p.epc_record.current_energy_efficiency + total_sap_points
             new_epc = sap_to_epc(new_sap_points)
             # Already installed measures do not have a cost but we remove anyway
             total_cost = sum([r["total"] for r in default_recommendations if not r["already_installed"]])
diff --git a/backend/ml_models/Valuation.py b/backend/ml_models/Valuation.py
index 17db0dae..64935dca 100644
--- a/backend/ml_models/Valuation.py
+++ b/backend/ml_models/Valuation.py
@@ -216,7 +216,7 @@ class PropertyValuation:
             cls.UPRN_VALUE_LOOKUP.get(property_instance.uprn)
         )
 
-        current_epc = property_instance.data["current-energy-rating"]
+        current_epc = property_instance.epc_record.current_energy_rating
 
         if not current_value:
             # In this case, we return a % improvement rather than an absolute
diff --git a/etl/epc/Record.py b/etl/epc/Record.py
index 10968edc..ecbb89d2 100644
--- a/etl/epc/Record.py
+++ b/etl/epc/Record.py
@@ -186,7 +186,7 @@ class EPCRecord:
     heat_loss_corridor: Optional[str] = None
     unheated_corridor_length: Optional[float] = None
 
-    mains_gas_flag: Optional[str] = None
+    mains_gas_flag: Optional[bool] = None
 
     # ------------------------------------------------------------------
     # BUILDING FABRIC DESCRIPTIONS