diff --git a/backend/app/plan/schemas.py b/backend/app/plan/schemas.py
index 447e0da2..29a7d5e3 100644
--- a/backend/app/plan/schemas.py
+++ b/backend/app/plan/schemas.py
@@ -86,6 +86,9 @@ class PlanTriggerRequest(BaseModel):
     # exists in the portfolio, it will be ignored
     multi_plan: Optional[bool] = False
 
+    # if False, allows optimisation to be switched off
+    optimise: Optional[bool] = False
+
     _allowed_goals = {"Increasing EPC"}
 
     _allowed_housing_types = {"Social", "Private"}
diff --git a/recommendations/HeatingRecommender.py b/recommendations/HeatingRecommender.py
index 48063a8e..7c26fcb6 100644
--- a/recommendations/HeatingRecommender.py
+++ b/recommendations/HeatingRecommender.py
@@ -812,20 +812,37 @@ class HeatingRecommender:
             new_heating_description = self.DUAL_HEATING_DESCRIPTIONS[
                 self.property.main_heating["clean_description"]
             ]["hhr"]["mainheating_description"]
+            new_hot_water_description = self.property.hotwater["clean_description"]  # We keep the hot water system
         else:
             new_heating_description = "Electric storage heaters"
+            new_hot_water_description = "Electric immersion, off-peak"
 
         # Set up artefacts, suitable for the simulation and regardless of controls
         heating_ending_config = MainHeatAttributes(new_heating_description).process()
         heating_simulation_config = check_simulation_difference(
             new_config=heating_ending_config, old_config=self.property.main_heating
         )
+
+        hot_water_end_config = HotWaterAttributes(new_hot_water_description).process()
+        hot_water_simulation_config = check_simulation_difference(
+            new_config=hot_water_end_config, old_config=self.property.hotwater
+        )
+
+        heating_simulation_config = {
+            **heating_simulation_config,
+            **hot_water_simulation_config
+        }
         # This upgrade will only take the heating system to average energy efficiency
-        if self.property.data["mainheat-energy-eff"] in ["Very Poor", "Poor"]:
+        if self.property.data["mainheat-energy-eff"] in ["Very Poor", "Poor"] and not self.dual_heating:
             heating_simulation_config["mainheat_energy_eff_ending"] = "Average"
         else:
             heating_simulation_config["mainheat_energy_eff_ending"] = self.property.data["mainheat-energy-eff"]
 
+        if self.property.data["hot-water-energy-eff"] in ["Very Poor", "Poor"]:
+            heating_simulation_config["hot_water_energy_eff_ending"] = "Average"
+        else:
+            heating_simulation_config["hot_water_energy_eff_ending"] = self.property.data["hot-water-energy-eff"]
+
         # If the property is off-gas and has no heating system in place, the number of heated rooms will actually
         # be 0, so we use the number of rooms as the figure
         number_heated_rooms = (
@@ -863,6 +880,8 @@ class HeatingRecommender:
         heating_description_simulation = {
             "mainheat-description": new_heating_description,
             "mainheat-energy-eff": heating_simulation_config["mainheat_energy_eff_ending"],
+            "hotwater-description": new_hot_water_description,
+            "hot-water-energy-eff": heating_simulation_config["hot_water_energy_eff_ending"]
         }
 
         recommendations = self.combine_heating_and_controls(