Model/domain/modelling/generators
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
..
__init__.py refactor(modelling): group domain/modelling into generators/scoring/optimisation 2026-06-03 13:48:36 +00:00
floor_recommendation.py refactor(modelling): type measure_type fields as MeasureType 2026-06-08 20:13:31 +00:00
glazing_recommendation.py modelling: glazing overlay models draught-proofing + frame-factor re-lodge 2026-06-24 08:25:08 +00:00
heating_recommendation.py Fix HHRSH storage heaters priced at peak rate (engine 48 vs Elmhurst 71) 2026-07-02 11:24:03 +00:00
lighting_recommendation.py feat(modelling): MeasureType StrEnum as the canonical measure vocabulary 2026-06-08 19:54:04 +00:00
roof_recommendation.py refactor(modelling): type measure_type fields as MeasureType 2026-06-08 20:13:31 +00:00
secondary_heating_recommendation.py feat(modelling): secondary-heating-removal generator + MeasureType (ADR-0028) 2026-06-11 13:35:14 +00:00
solar_recommendation.py fix(pv): credit PV only when connected to the dwelling's meter 🟩 2026-06-29 13:40:51 +00:00
solid_wall_recommendation.py refactor(modelling): type measure_type fields as MeasureType 2026-06-08 20:13:31 +00:00
ventilation_recommendation.py feat(modelling): MeasureType StrEnum as the canonical measure vocabulary 2026-06-08 19:54:04 +00:00
wall_recommendation.py feat(modelling): MeasureType StrEnum as the canonical measure vocabulary 2026-06-08 19:54:04 +00:00