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141 commits

Author SHA1 Message Date
Khalim Conn-Kowlessar
48ce18dbb6 Fabric spend comes out of the shared budget before phase 2 🟩
Documents behaviour already delivered by the phase-2 structure: the leftover
budget is the envelope minus the committed fabric cost, so a heating system
the plain optimiser would buy can be priced out. Test passed on arrival.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-09 11:41:22 +00:00
Khalim Conn-Kowlessar
705c86d5e6 Phase-2 candidates are valued against the post-fabric dwelling 🟥
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-09 11:40:29 +00:00
Khalim Conn-Kowlessar
e880ae868c Fabric short of the target is topped up with non-fabric measures 🟥
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-09 11:36:43 +00:00
Khalim Conn-Kowlessar
fcf46263bc Fabric-first scenario stops at fabric when the target is met 🟥
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-09 11:36:02 +00:00
Khalim Conn-Kowlessar
5d0a7751e6 A small-roof house gets Sub-Ladder solar Options instead of nothing 🟩
End-to-end pin at the generator seam (recommend_solar) — passed on first
run since option construction is unchanged by design (ADR-0058).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:09:18 +00:00
Khalim Conn-Kowlessar
024a01b128 The Dwelling-Roof Cap bounds Sub-Ladder rungs too 🟩
Pins that the unchanged cap regime (min of 0.7×Google and the ADR-0038
budget) flows into ADR-0058 derivation — no red phase; the tracer
implementation passed the already-min'd cap through.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:08:28 +00:00
Khalim Conn-Kowlessar
1756976d7e A roof capped below two panels is still offered no PV 🟩
Pins the ADR-0058 install floor delivered with the tracer slice (rung_max
< 2 returns empty) — no red phase.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:07:39 +00:00
Khalim Conn-Kowlessar
5a382948d5 Sub-Ladder rungs never take from north planes 🟩
Pins behavior delivered with the tracer slice (derivation starts from the
north-dropped remainder) — no red phase; the mutation is discriminating
(a kept north panel would win fill-by-generation and shift the yields).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:07:18 +00:00
Khalim Conn-Kowlessar
0b33f7dc65 Sub-Ladder rungs fill from the highest-yield segment first 🟥
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:06:10 +00:00
Khalim Conn-Kowlessar
79d7743bb1 A small roof derives Sub-Ladder rungs below Google's smallest config 🟥
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 22:03:43 +00:00
Khalim Conn-Kowlessar
128981289a Floor insulation is withheld when it cannot lower the derived floor U 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 16:05:04 +00:00
Jun-te Kim
23ebd5e637
Merge pull request #1446 from Hestia-Homes/fix/ashp-size-to-dwelling-heat-loss
Size the ASHP to the dwelling's design heat loss (fix undersized fixed pump scoring below baseline)
2026-07-03 13:32:30 +01:00
Khalim Conn-Kowlessar
da4aec9840 Treatable old-band solid walls keep their EWI and IWI options under the gate 🟩
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 11:41:56 +00:00
Khalim Conn-Kowlessar
5f74c34f9a Cavity fill is withheld when it cannot lower the derived wall U 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 11:41:02 +00:00
Khalim Conn-Kowlessar
574e58a5c8 Solid-wall insulation is withheld when it cannot lower the derived wall U 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 11:39:32 +00:00
Khalim Conn-Kowlessar
bf240e3315 ASHP sizing targets the Appendix-N efficiency peak (realistic installed pump) 🟩
Sizing selects the aroTHERM plus rung nearest PSR ~0.8 (0.8 x design heat
loss) — the Appendix-N efficiency peak, reproducing the pump a real
installer fits — rather than the MCS PSR>=1.0 capacity target, which
oversizes. Validated against the relodged Elmhurst ASHP cert (delta 0
held at the 5 kW Vaillant); the two self-snapshot pins re-pin to their
correctly-sized larger pumps, and the orchestrator/harness thread the
calculator's design heat loss so production sizes to the dwelling. Manual
SapResult test stubs carry the new design_heat_loss_kw field.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 11:02:13 +00:00
Khalim Conn-Kowlessar
6f70e65bc4 ASHP cost sizes to the threaded design heat loss over the floor-area proxy 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 10:29:14 +00:00
Khalim Conn-Kowlessar
2dd637a657 The ASHP bundle sizes the heat pump to the dwelling's design heat loss 🟩
_ashp_option now selects the aroTHERM plus PCDB record matching the
threaded design heat loss (floor-area proxy fallback), so the overlay's
efficiency anchor is sized to the dwelling instead of a fixed 5 kW unit.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 10:28:08 +00:00
Khalim Conn-Kowlessar
df38dda7b0 The ASHP bundle sizes the heat pump to the dwelling's design heat loss 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 10:26:35 +00:00
Khalim Conn-Kowlessar
7707df3294 ASHP sizing caps at the largest pump for a high-heat-loss dwelling 🟩
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 10:14:10 +00:00
Khalim Conn-Kowlessar
b37be6327c ASHP sizing selects the smallest pump meeting the dwelling's design heat loss 🟥
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-03 10:13:19 +00:00
Jun-te Kim
4ca3491eb2
Merge pull request #1426 from Hestia-Homes/fix/hhrsh-storage-offpeak-pricing
Fix HHRSH storage heaters priced at peak rate (engine 48 vs accredited Elmhurst 71)
2026-07-02 12:50:32 +01:00
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
Khalim Conn-Kowlessar
0efae77fd2 An unlodged roof type with ND thickness gets no roof recommendation 🟥
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 11:18:55 +00:00
Khalim Conn-Kowlessar
989cd61574 ND loft roof on a pre-1950 dwelling gets loft insulation 🟥
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 11:04:40 +00:00
Khalim Conn-Kowlessar
b33735ef30 NI (insulation present) and measured depths keep a vaulted roof ineligible 🟩
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 11:03:38 +00:00
Khalim Conn-Kowlessar
1dd2d19f78 ND on a limited-insulation age band yields no roof recommendation 🟩
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 11:03:01 +00:00
Khalim Conn-Kowlessar
0d465346c9 Vaulted ND roof on a pre-1950 dwelling gets sloping-ceiling insulation 🟥
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-02 10:55:58 +00:00
Jun-te Kim
5b4a1b4966 Classify PCDB-index gas boilers with no SAP code for heating recs
Gov-API certs that lodge a gas boiler as main_heating_category=2 + a PCDB
main_heating_index_number but omit sap_main_heating_code were carried with
a null code, so the heating generators (which gated on sap_main_heating_code
alone) never evaluated them for a boiler upgrade or a system tune-up — they
silently got nothing (£0 works, plateau at D). The SAP calculator already
handles this shape (cert_to_inputs._is_wet_boiler_main), so the calculator
modelled these as wet boilers while the recommenders ignored them.

Mirror the calculator's classification in the generator:
- _is_wet_boiler / _is_electric_boiler fall back, when no SAP code is
  lodged, to a PCDB Table 105 boiler index or main_heating_category in
  {1,2} (heat pumps excluded); electric boilers stay excluded by the code
  range when lodged, else by an electricity main fuel.
- _already_condensing reads the boiler's declared PCDB winter efficiency
  when there is no Table 4b code, so a modern condensing boiler lodged this
  way still isn't offered a pointless like-for-like swap (gets a tune-up).

Verified read-only on portfolio 814 / scenario 1271: pids 742304, 742306,
742322, 742325, 742336 now get a gas_boiler_upgrade (two cross D->C on the
boiler alone) where they had £0 works; predicted properties whose heating
donor is a PCDB-shape boiler (e.g. 742095/742102/742105) also recover a
tune-up. Fixes the A#2 slice of #1388 (and unblocks 742302/742367).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-01 14:52:47 +00:00
Daniel Roth
576fc948a6 Gate community-heated dwellings from ASHP recommendation 🟥
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-01 14:17:41 +00:00
Daniel Roth
afe6638b36 Gate community-heated dwellings from HHRSH recommendation 🟥
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-01 14:13:57 +00:00
Daniel Roth
9b58bebfb8 Rename SapEnergySource.mains_gas to gas_connection_available 🟩
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-01 10:59:21 +00:00
Daniel Roth
a174301136 rename mains_gas to gas_connection_available 2026-07-01 10:50:58 +00:00
Daniel Roth
5d99956133 On-gas-street electric dwelling (API fuel code 29) is offered HHRSH 🟥
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-01 10:36:52 +00:00
Daniel Roth
266a276dae revert changes 2026-07-01 09:52:06 +00:00
Daniel Roth
0192dd8efd HHRSH not offered to solid-biomass dwelling with mains_gas=True despite off-gas heating fuel 🟥
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-01 09:41:09 +00:00
Khalim Conn-Kowlessar
8606cab5f0 fix(pv): credit PV only when connected to the dwelling's meter 🟩
Gate PV generation/credit in cert_to_inputs on gov-API pv_connection:
credit only when ==2 ('connected'); ==1 ('present but not connected to the
dwelling's meter') contributes zero to the dwelling's cost/CO2/PE per
RdSAP 10 §11.1 / SAP 10.2 Appendix M. Non-int (None / site-notes str) keeps
the credit-if-array behaviour, so the Elmhurst/Summary + synthetic paths are
unchanged (no regression).

Corpus: all 5 pv_connection=1 PV certs move inside ±0.5 (e.g. 100051118081
+6.5→+0.5); MAE 0.760→0.740, within-0.5 73.8→74.3%, no regression
(pv_connection=2 certs keep their credit).

Also corrects a now-load-bearing latent bug: the solar-recommendation
overlay tagged recommended arrays pv_connection=1 ('not connected') — which
the new gate would zero. A new install connects to the dwelling's meter, so
it must be 2; pinned by the overlay test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-29 13:40:51 +00:00
Khalim Conn-Kowlessar
0a2ed67e94 Harden Dwelling-Roof Cap on real data: positional segments, ground-floor basis 🟩
Three corrections found by re-running property 742003 end-to-end:
- roofSegmentStats are POSITIONAL — real responses omit the segmentIndex field
  the fixture happened to carry; key the centre/area lookup by array position.
- Base the cap on ground_floor_area (the footprint the roof covers), not the
  greatest per-storey area; roof_area is the fallback.
- Clamp the basis by total_floor_area: predicted EPCs borrow the structural
  template's geometry (742003: a 118.62 m² MAIN ground floor) decoupled from
  the predicted 55 m² (ADR-0029), so without the clamp the cap reads the
  template's larger footprint.

Result: 742003 plan A/92.4 (16 kWp) -> C/74.4 (6.4 kWp). 29 solar tests +
orchestration threading + products green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-26 12:24:52 +00:00
Khalim Conn-Kowlessar
904c205e3a Dwelling-Roof Cap bounds the PV array to the dwelling's own roof 🟥
select_conservative_configs must accept the dwelling's roof area and cap panels
to its usable roof (ADR-0038) — bounding a 55m² dwelling to ~16 panels under
Google footprint conflation, while staying a no-op on correctly-matched homes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-26 12:15:28 +00:00
Khalim Conn-Kowlessar
cf2780ed77 SolarPotential carries panel dims + per-segment centre/area 🟥
The Dwelling-Roof Cap (ADR-0038) sizes by usable roof area and ranks segments
by distance from the dwelling, so the projection must carry each panel's
footprint and each segment's centre + area (from roofSegmentStats).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-26 12:12:12 +00:00
Jun-te Kim
46fc8f338c
Merge pull request #1289 from Hestia-Homes/fix/solar-missing-max-array-panels
Treat solar block without array sizing as no-solar (fix KeyError maxArrayPanelsCount, 2 e2e failures)
2026-06-24 11:59:57 +01:00
Jun-te Kim
79f89d872e Treat solar block without array sizing as no-solar (fix KeyError)
2 modelling_e2e properties failed with KeyError: 'maxArrayPanelsCount'.

Google returns a `solarPotential` block with no array-level sizing fields
(`maxArrayPanelsCount` / `panelCapacityWatts`) for buildings with no usable
solar estimate. `SolarPotential.from_building_insights` hard-indexed those keys
and crashed the whole property.

Fix: the projection now returns Optional and yields None when those fields are
absent — the established "no solar potential" outcome (the orchestrator and
recommendation path already type it Optional and skip solar on None). Existing
callers (`_solar_potential_for`, harness) already assign to Optional.

Regression test + `assert is not None` narrowing on the valid-fixture tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-24 10:22:06 +00:00
Khalim Conn-Kowlessar
80d617aa5b modelling: glazing overlay models draught-proofing + frame-factor re-lodge
Fitting sealed glazing units changes two things beyond the pane's U/g
that the cascade reads, which the overlay didn't model — leaving the
double/secondary before→after pins ~0.7 SAP short (xfail):

1. Draught-proofing (RdSAP 10 §8.1). Sealed units draught-proof the panes
   they replace, re-lodging the dwelling-level `percent_draughtproofed`
   (cert 001431: 84 → 100). The §2 cascade reads that dwelling-level
   value, so the overlay now carries it. `_recompute_percent_draughtproofed`
   anchors on the lodged before-% — `after = round((round(before%/100 × N)
   + flips) / N × 100)`, N = openable windows (vertical + roof) + doors,
   flips = upgraded panes that were not draught-proofed — so it's robust
   to incomplete window extraction (unchanged openings are already in the
   aggregate). ~0.3 SAP.

2. Frame factor (§6 solar gains). A replacement unit re-lodges its own
   FF=0.70, overriding the pane it replaced — the two "single glazing,
   known data" panes lodge FF 1.00 / 0.50 (one is 6.6 m²), so leaving them
   unchanged understated solar gains by ~+150 kWh space heating. `WindowOverlay`
   now carries `frame_factor`, written flat onto the window. ~0.4 SAP.

Wiring: `EpcSimulation.percent_draughtproofed` + `WindowOverlay.frame_factor`
new fields; `apply_simulations` / `_fold_window` write them; the glazing
generator computes both from the upgraded set and cert 001431's after.

Un-xfails `test_{double,secondary}_glazing_overlay_reproduces_the_relodged_after`
— both now pin SAP/CO2/PE to the relodged after within tolerance. Updates
the two `test_glazing_recommendation` overlay expectations for the new
`frame_factor`. 96 modelling tests pass; zero new pyright errors.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-24 08:25:08 +00:00
Jun-te Kim
9956df07ff Land an override on the EPC's part at its position when the label is absent 🟩
A Landlord Override's building_part is a positional index (0=main, 1=extension
1…, ADR-0004), but the gov-API EPC can label that slot differently (e.g. lodge
the 2nd part as 'other', not 'extension_1'). The previous fix skipped such
orphaned overrides, silently discarding the landlord's correction. Now the
override falls back onto the EPC's part at that position (via _resolve_part), so
the correction lands; only a position the EPC models no part at is skipped
(no geometry to model a wholly-absent part). Replaces the skip-only behaviour.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 17:09:11 +00:00
Jun-te Kim
539f661430 Skip a landlord override that targets a building part the EPC lacks 🟥
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 15:35:19 +00:00
Jun-te Kim
a3e2566378 landlord override data added 2026-06-20 12:57:54 +00:00
Khalim Conn-Kowlessar
fc7c4d2d3b fix(climate): compute EPC CO2/PE on the postcode demand cascade (SAP 10.2 Appendix U p.124)
The SAP/EI rating is computed on UK-average weather (Appendix U Tables
U1-U3 region 0) so ratings are nationally comparable, but Appendix U
paragraph 1 (PDF p.124) requires that "other calculations (such as for
energy use and costs on EPCs) are done using local weather. Weather data
for each postcode district are taken from the PCDB". `Sap10Calculator.
calculate` ran ONE cascade (UK-average) and fed it to SAP, CO2 AND primary
energy, so every cert's EPC-displayed CO2/PE were computed on the wrong
climate. Because most of England is warmer than the UK-average, this
systematically OVER-counted heating demand on the emissions/PE outputs.

The two cascades (`cert_to_inputs` rating, `cert_to_demand_inputs`
postcode) already existed; this wires the demand cascade into the
production entry point and grafts its CO2/PE onto the rating result (SAP
unchanged). The corpus gauge's longstanding +5% CO2/PE over-estimate was
mostly this climate bug, NOT (as previously diagnosed) per-cert mapper
fidelity:
  CO2 MAE 0.26 -> 0.12 t/yr  (bias +0.18 -> +0.04)
  PE  MAE 13.6 -> 3.8 kWh/m2 (bias +9.0  -> +0.24)
  SAP within-0.5 = 69.7% (rating cascade, unchanged)

Worksheet-validated to 1e-4 on simulated case 45 (heat-pump ground-floor
flat, postcode W6): the P960 prints the current dwelling twice — Block 1
on UK-average weather (SAP 60.5318, CO2 692.13) and Block 2 on postcode
weather (CO2 626.78, PE 6581.59). Both reproduce exactly. Added a tracked
case-45 Summary fixture + two-cascade cascade pin as a permanent guard,
and ratcheted the corpus CO2/PE ceilings to 0.13 / 4.2. The e2e Elmhurst
suite (Block-1 line refs) now pins the rating cascade directly; the two
Vaillant overlay snapshots refreshed to demand-cascade CO2/PE.

pyright not installed in this codespace (strict gate not run locally);
change is type-trivial (dataclasses.replace over SapResult).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-18 14:15:34 +00:00
Khalim Conn-Kowlessar
3580d059ec feat(modelling): drive measure scoping from the Scenario's exclusions
The measures a run considers should come from the Scenario, not a CLI flag.
The live scenario table persists exclusions only (no inclusions column), as a
Postgres text-array of exact MeasureType values.

- Scenario gains `exclusions: frozenset[MeasureType]` + `considered_measures()`
  (all measures minus the excluded ones, or None when none are excluded).
- ScenarioModel.to_domain parses the `{a,b,c}` exclusions array into
  MeasureTypes, raising on a token that is not an exact MeasureType value
  (no high-level category expansion), per the strict-enum convention.
- ModellingOrchestrator._plan_for derives the allowlist from the Scenario's
  exclusions, combined (intersection) with any explicit considered_measures
  override via the new `combine_considered_measures`.
- run_modelling_e2e sources the allowlist from the Scenario; --measures /
  --exclude-measures become optional overlays (e.g. the technical
  secondary_heating_removal exclusion the catalogue cannot yet stock).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-16 15:26:25 +00:00
Khalim Conn-Kowlessar
53d9f21f73 fix(modelling): offer ASHP when the catalogue has no ASHP row
The ASHP bundle is priced from the rate sheet (ADR-0025); the catalogue
row is read only for its material id, which is nullable end-to-end. The
live `material` catalogue has no `air_source_heat_pump` row, so
`products.get` raised `ValueError: no active product` and aborted every
ASHP-eligible property.

Add `ProductNotFound(ValueError)` + a concrete `ProductRepository
.get_optional`, raise the typed error from both repos, and have
`_ashp_option` look the row up optionally — a missing row now yields an
ASHP Option with `material_id=None` rather than crashing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-16 14:55:41 +00:00
Khalim Conn-Kowlessar
c11eb46b8a fix(modelling): HHR overlay sets off-peak immersion type so HW Table 13 applies
The HHR-storage HeatingOverlay (ADR-0024) added an off-peak electric
immersion cylinder but never set `immersion_heating_type`, so the overlaid
cert left it None. The calculator then could not resolve `immersion_single`
for the SAP 10.2 Table 13 HW high-rate split and billed hot water 100% at
the off-peak low rate — £127.41 vs the relodged after-cert's £169.39,
overstating the overlay's SAP by +1.26 (CO2/PE matched, isolating it to the
HW cost path).

Add `immersion_heating_type` to HeatingOverlay, route it through
`_fold_heating` (it lives on `sap_heating`), and set it to 1 (single
off-peak immersion) on the HHR overlay to match the relodged reference.
Closes both `test_hhr_storage_overlay_reproduces_the_relodged_after_*`
cascade pins (electric-storage and no-system befores share the after).

Pre-existing failure (present before this branch's recent commits), outside
the handover regression gate. Full modelling suite 220 pass, pyright net-
zero.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-15 06:53:14 +00:00