diff --git a/tests/domain/epc/test_main_heating_system_overlay.py b/tests/domain/epc/test_main_heating_system_overlay.py
index 266e14415..40998c7d7 100644
--- a/tests/domain/epc/test_main_heating_system_overlay.py
+++ b/tests/domain/epc/test_main_heating_system_overlay.py
@@ -108,6 +108,20 @@ def test_overlay_logs_when_it_cannot_complete_a_companion_set(
     assert "Air source heat pump" in caplog.text
 
 
+def test_complete_room_heater_overlay_does_not_log_a_companion_gap(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    # Electric room heaters now resolve a full companion set (category 10 +
+    # control 2601), so the overlay must NOT log an incomplete-companion gap —
+    # guarding that the fix keeps the set complete.
+    # Act
+    with caplog.at_level(logging.ERROR):
+        main_heating_overlay_for("Electric room heaters", 0)
+
+    # Assert
+    assert "incomplete companion set" not in caplog.text
+
+
 @pytest.mark.parametrize(
     ("main_heating_value", "code"),
     [