diff --git a/tests/domain/modelling/test_heating_recommendation.py b/tests/domain/modelling/test_heating_recommendation.py
index 4f1a321a6..4a4687580 100644
--- a/tests/domain/modelling/test_heating_recommendation.py
+++ b/tests/domain/modelling/test_heating_recommendation.py
@@ -23,9 +23,11 @@ from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
     build_epc,
 )
 
-# Electricity main-fuel code (Elmhurst → SAP10) and the Table 4a SAP code an
-# existing (non-HHR) electric storage system lodges.
+# Electricity fuel codes and the Table 4a SAP code an existing (non-HHR)
+# electric storage system lodges.  30 is the SAP Table 12 code (used by
+# Elmhurst / cascade); 29 is the raw gov-API enum that some certs carry.
 _ELECTRICITY = 30
+_API_ELECTRICITY = 29
 _OLD_STORAGE_SAP_CODE = 402
 
 
@@ -138,6 +140,24 @@ def test_hhr_storage_bundle_carries_the_product_cost_and_contingency() -> None:
     assert abs(option.cost.contingency_rate - 0.26) <= 1e-9
 
 
+def test_on_gas_street_electric_dwelling_yields_hhr_storage_bundle() -> None:
+    # Arrange — electrically heated dwelling whose cert carries the raw API
+    # fuel code (29) instead of the SAP Table 12 code (30), AND has a mains-
+    # gas connection at the street (mains_gas=True, the default for 000490).
+    # Bug: off_gas = not True = False; electric_main = 29 == 30 = False →
+    # HHRSH incorrectly blocked.  Fix: key on main_fuel_type not in _GAS_FUEL_CODES.
+    baseline: EpcPropertyData = _electric_storage_baseline()
+    baseline.sap_heating.main_heating_details[0].main_fuel_type = _API_ELECTRICITY
+
+    # Act
+    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())
+
+    # Assert — dwelling heats electrically (not with gas) → HHRSH must be offered.
+    assert recommendation is not None
+    options = {o.measure_type.value: o for o in recommendation.options}
+    assert "high_heat_retention_storage_heaters" in options
+
+
 def _gas_boiler_house() -> EpcPropertyData:
     """A 000490 mains-gas combi dwelling, explicitly a House — ASHP-eligible."""
     epc: EpcPropertyData = build_epc()