diff --git a/domain/modelling/generators/heating_recommendation.py b/domain/modelling/generators/heating_recommendation.py
index 3ba716d6a..f0c0ccec9 100644
--- a/domain/modelling/generators/heating_recommendation.py
+++ b/domain/modelling/generators/heating_recommendation.py
@@ -225,8 +225,8 @@ _RADIATOR_ROOM_OFFSET = 3
 _RADIATOR_M2_PER_RADIATOR = 13.0
 # main_fuel_type codes (gov API enum and/or Table 12) by fuel. Classification
 # keys on the heating *fuel*, NOT the `mains_gas` flag — that flag means gas is
-# available at the property, which is True even for electrically-heated dwellings
-# on a gas street (every 001431 electric fixture lodges mains_gas=True).
+# available at the property, which is True for any dwelling on a gas street
+# regardless of its actual heating fuel (electric, oil, solid biomass, etc.).
 _GAS_FUEL_CODES = frozenset({26, 1})
 _OIL_FUEL_CODES = frozenset({28, 4, 71, 73, 75, 76})
 _LPG_FUEL_CODES = frozenset({27, 2, 3, 5, 9})