diff --git a/domain/modelling/generators/heating_recommendation.py b/domain/modelling/generators/heating_recommendation.py
index 9eae0353e..d9564f069 100644
--- a/domain/modelling/generators/heating_recommendation.py
+++ b/domain/modelling/generators/heating_recommendation.py
@@ -714,14 +714,15 @@ def _hhr_storage_option(
 
 
 def _hhr_storage_eligible(epc: EpcPropertyData) -> bool:
-    """HHR storage suits an electrically-heated or off-gas dwelling, unless it is
-    already HHR or a heat pump (translated from legacy `HeatingRecommender.
-    is_high_heat_retention_valid`, which keyed on description strings)."""
+    """HHR storage suits a non-gas-fuel dwelling, unless it is already HHR or a
+    heat pump.  Eligibility keys on the heating *fuel* (main_fuel_type not in
+    _GAS_FUEL_CODES), not the gas-connection flag — a dwelling on a gas street
+    with electric or oil heating has gas_connection_available=True but still
+    qualifies."""
     main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
     if main.sap_main_heating_code == _HHR_STORAGE_SAP_CODE:
         return False
     if main.main_heating_category == _HEAT_PUMP_CATEGORY:
         return False
-    off_gas: bool = not epc.sap_energy_source.mains_gas
-    electric_main: bool = main.main_fuel_type == _ELECTRICITY_FUEL
-    return electric_main or off_gas
+    non_gas_fuel: bool = main.main_fuel_type not in _GAS_FUEL_CODES
+    return non_gas_fuel