diff --git a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
index d6b61a64..dfb21f1e 100644
--- a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
+++ b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
@@ -650,6 +650,34 @@ def test_api_0380_heat_pump_no_secondary_heating_per_table_11() -> None:
     assert result.secondary_heating_fuel_kwh_per_yr == 0.0
 
 
+def test_api_0380_heat_pump_no_pumps_fans_kwh_per_table_4f() -> None:
+    # Arrange — SAP 10.2 Table 4f lists annual pumps + fans electricity
+    # consumption by main heating category. Gas-fired boilers (cat 2)
+    # use 160 kWh/yr (115 central heating pump + 45 flue fan). Heat
+    # pumps (cat 4) have NO additional pumps/fans contribution because
+    # the HP system's circulation pump and fans are already
+    # incorporated into the system COP.
+    #
+    # The cascade's `_PUMPS_FANS_KWH_BY_MAIN_CATEGORY` dict only had a
+    # cat-2 entry; cat-4 HP certs fell through to the DEFAULT 130
+    # kWh/yr (~£17 at 13.19 p/kWh) — the worksheet line (249) "Pumps,
+    # fans and electric keep-hot" shows 0.0000 kWh/yr for cert 0380.
+    doc = json.loads(_API_0380_JSON.read_text())
+    epc = EpcPropertyDataMapper.from_api_response(doc)
+
+    # Act
+    from domain.sap10_calculator.calculator import calculate_sap_from_inputs
+    from domain.sap10_calculator.rdsap.cert_to_inputs import (
+        cert_to_inputs, SAP_10_2_SPEC_PRICES,
+    )
+    result = calculate_sap_from_inputs(
+        cert_to_inputs(epc, prices=SAP_10_2_SPEC_PRICES)
+    )
+
+    # Assert
+    assert result.pumps_fans_kwh_per_yr == 0.0
+
+
 def test_api_9501_room_in_roof_surfaces_populated() -> None:
     # Arrange — cert 9501's API JSON lodges measured RR detail under
     # `sap_room_in_roof.room_in_roof_details`: two gable walls
diff --git a/domain/sap10_calculator/rdsap/cert_to_inputs.py b/domain/sap10_calculator/rdsap/cert_to_inputs.py
index e0910422..45aa4096 100644
--- a/domain/sap10_calculator/rdsap/cert_to_inputs.py
+++ b/domain/sap10_calculator/rdsap/cert_to_inputs.py
@@ -173,6 +173,11 @@ _DEFAULT_PUMPS_FANS_KWH_PER_YR: Final[float] = 130.0
 # (Table 4f spec lines 7905-8076) — deferred until a fixture exercises.
 _PUMPS_FANS_KWH_BY_MAIN_CATEGORY: Final[dict[int, float]] = {
     2: 160.0,   # Gas-fired boilers (115 pump + 45 flue fan)
+    4: 0.0,     # Heat pumps — circulation pump + fans already in COP
+                # per SAP 10.2 Table 4f. Worksheet line (249) shows
+                # 0 kWh on cert 0380 (HP ASHP). Without this explicit
+                # entry HP certs fell through to the 130 kWh/yr DEFAULT
+                # and over-billed £17/yr at electricity rate.
 }
 # SAP10.2 Table 6d note 1: "average or unknown" overshading is the
 # default for existing dwellings. RdSAP doesn't lodge a per-dwelling