Model/tests/domain/sap10_calculator
Jun-te Kim f5fbeb8e7e Fix HHRSH storage heaters priced at peak rate (engine 48 vs Elmhurst 71)
The high-heat-retention storage-heater (HHRSH) recommendation was computed
as LOWERING SAP and wrongly rejected by the Optimiser, leaving electric-
room-heater flats/maisonettes stuck at band E with no sensible plan.

Root cause: `_HHR_STORAGE_OVERLAY` sets `sap_main_heating_code=409` (HHR
storage) + `meter_type="Dual"` but left `main_heating_category` at the
pre-existing value (10 = electric room heaters). The SAP 10.2 Table 12a
space-heating high-rate-fraction resolver classifies by category, so it
misread the off-peak storage heating as direct-acting electric (1.00
high-rate) and priced 100% at the 7-hour peak rate (15.29p) instead of the
storage off-peak split (0.00, ~5.5p).

Verified against accredited Elmhurst RdSAP-10 on UPRN 100020942571
(8 Booth Close, SE28 8BW): engine HHRSH SAP 48 (peak-priced, cost £1087)
vs Elmhurst 71 (cost ~£611); with the fix the engine gives 73 / £576.

Two-part fix (defence in depth, so no future overlay/mapper can
reintroduce it):
- `_HHR_STORAGE_OVERLAY` now sets `main_heating_category=7`, keeping the
  overlaid EPC internally consistent.
- `_table_12a_system_for_main` now classifies electric storage heaters by
  their Table 4a SAP code (401-409) as well as `category==7`, checked
  before the room-heater branch, so a specific storage code is
  authoritative over a stale/inconsistent category.

Tests: new regression `test_storage_heater_classified_by_sap_code_over_stale_category`;
updated the HHRSH overlay pin. Full accuracy corpus still passes (no regressions).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 11:24:03 +00:00
..
climate Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
rdsap Fix HHRSH storage heaters priced at peak rate (engine 48 vs Elmhurst 71) 2026-07-02 11:24:03 +00:00
validation Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
worksheet test(worksheet): pin simulated case 50 — MVHR + dual-immersion all-electric 2026-06-24 09:07:16 +00:00
__init__.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_bre_worked_examples.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_calculator.py Thread the off-peak meter flag and high-rate fractions onto SapResult 🟩 2026-06-24 17:45:29 +00:00
test_pcdb_etl.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_pcdb_lookup.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_pcdb_table_322_lookup.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_pcdb_table_323_lookup.py feat(pcdb): parse Table 323 (Centralised MEV / MVHR) + Table 329 efficiency IUF 2026-06-23 19:29:17 +00:00
test_pcdb_table_329_lookup.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_pcdb_table_362_lookup.py test(pcdb): PSR-extension toward 100% above largest / below smallest 🟥 2026-06-29 15:08:15 +00:00
test_postcode_weather.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_real_cert_sap_accuracy.py Re-baseline pins for full-SAP PV + tariff mapper fixes 🟩 2026-06-30 09:18:39 +00:00
test_table_12.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_table_12a.py feat(tariff): complete §12 Unknown-meter clause — GSHP/WSHP main triggers off-peak (RdSAP 10 PDF p.62) 2026-06-23 10:09:59 +00:00
test_table_13.py fix(water-heating): 18-/24-hour immersion DHW bills 100% low-rate (Table 12a scope) 2026-06-10 22:01:35 +00:00
test_table_32.py Map fuel code 39 (electricity, any tariff) to standard electricity 2026-06-24 11:20:32 +00:00