The PV-array (ea7f4f43) and electricity-tariff (6ec09892) mapper fixes shifted
the observed output of five frozen gates that weren't updated alongside:
- has_pv component-accuracy floor 0.9798 -> 0.9697: carrying full-SAP lodged PV
now reads the true has_pv=True for full-SAP PV dwellings, so the leave-one-out
scorer's actual changes (ground-truth-method shift, ADR-0037 pattern).
- uprn_10093116528 80->... pin 82 -> 83: tariff=1 (standard) was wrongly read as
dual/Economy 7; translating to "single" re-prices the gas semi's electricity.
- uprn_10096028301 82 -> 84, uprn_10023444324 80 -> 82 (== lodged 82),
uprn_10023444320 81 -> 83: now credit the lodged sap_energy_source.pv_arrays
the schema previously dropped. Comments document the per-cert PV/Elmhurst
relationship (incl. the mid-floor sibling landing +2 over its lodged integer).
Pre-existing, unrelated failures untouched: the missing
sap_16_0_full_no_floor_dims.json fixture and the RdSAP-21 floor-area test (both
reproduce on origin/main).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Appendix N3.7 ("Thermal efficiency for water heating - heat pumps",
PDF p.109): "multiply the thermal efficiency for water heating by the in-use
factor in Table N8; subject to a minimum efficiency of 100%." Our
_heat_pump_apm_efficiencies applies the in-use factor but omits the floor.
Anchored to golden fixture case 56 (PCDB 100061, cert 100110101713): an
oversized HP (PSR 3.107) extends water,3 198.9% -> 128.55%, x 0.60 in-use =
77.13% < 100% -> the accredited Elmhurst worksheet (216) reads 100.0000, we
read 77.13%. In-range PSR keeps 0.60 x 198.9 = 119.34% (above the floor).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Appendix N2 (PDF p.101, footnote 44/45): for an air/ground/water
source heat pump whose plant size ratio exceeds the record's largest PSR,
the efficiency is reciprocal-interpolated between the largest-PSR value and
100% at twice the largest PSR (100% beyond that); below the smallest PSR the
efficiency is 100%. Our interpolator instead clamps to the top/bottom row.
Anchored to the accredited Elmhurst worksheet for cert 100110101713 (golden
fixture case 56, PCDB 100061): PSR 3.10665 over the record's largest 2.0
gives eta_space,1 = 147.011 -> (206) = 0.95 x 147.011 = 139.660, vs the
clamped 352.0 -> 334.4% that over-rates the dwelling by +18 SAP.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
RdSAP 10 §11.1 / SAP 10.2 Appendix M: PV is included in a dwelling's
assessment only if connected to the dwelling's own electricity meter. The
gov-API pv_connection enum encodes this — 0=no PV, 1=present-but-not-
connected, 2=connected. Corpus-validated (57 PV certs: pv_connection=1 MAE
4.48->1.22 without credit, 0/5 need it; pv_connection=2 needs it, MAE 0.98
vs 10.29) and Elmhurst-proven (connected SAP 87 vs not-connected 74).
cert_to_inputs currently credits a pv_connection=1 array; the test pins that
it must contribute zero generation. Adds pv_connection to make_minimal_sap10_epc.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A gov-API flat can lodge dwelling_type="Mid-floor flat" while carrying its
own exposed roof — a top-floor flat mislabelled mid-floor. _dwelling_exposure
keyed roof exposure on the dwelling_type label alone, dropping the roof
heat-loss term: space-heating demand under-read ~32%, SAP over-read +7.
Fix: when the main building part lodges a *determined* roof_insulation_location
(an RdSAP integer code, not the "ND" Not-Defined party-ceiling sentinel),
expose the roof regardless of a contradictory label. Structured field, not a
description string and not roof_construction (which the gov-API lodges
building-wide on every unit, so it is not a per-unit signal).
On the RdSAP-21.0.1 corpus roof_insulation_location separates the classes with
zero disagreement: all 190 party-ceiling flats lodge "ND"; the 4 mid/ground
flats this exposes all move toward lodged, 0 away. within-0.5 73.3% -> 73.6%,
MAE 0.774 -> 0.761 (ratchets tightened). Verified end-to-end on the same
block: 715363 (location 6, RHI 2694) 81 -> 74 = lodged; genuine mid-floor
sibling 715395 (location ND, RHI 1024) stays party at 83 = lodged.
The override is additive (only ever exposes a label-dropped roof) and reads
the main part, so multi-part flats with a party main ceiling stay party.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A gov-API cert can lodge dwelling_type="Mid-floor flat" while carrying a
real exposed roof element (roof_construction != 7 "dwelling above") over a
"(another dwelling below)" floor — i.e. a top-floor flat mislabelled
mid-floor. Property 715363 (uprn 6027561) + sibling 715395 (6027563) do
exactly this; the correctly-labelled top-floor sibling 715871 (6027574),
same block + same flat roof, already computes the lodged SAP 74.
_dwelling_exposure keys roof exposure on the dwelling_type label alone, so
it drops the roof heat-loss term, under-reading space-heating demand ~32%
(calc 1833 vs lodged RHI 2694) and over-reading SAP +7 (81 vs 74).
Pins the fix: a mid-floor label + lodged exposed roof must expose the roof
(floor stays party). Also corrects the existing mid-floor fixture to lodge
the party-ceiling code 7 (the default 4 is an exposed pitched roof).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Surface the hot-water (Table 13 / HP-DHW), secondary (direct-acting),
main-2 and ALL_OTHER_USES High-Rate Fractions on CalculatorInputs from
the same Table 12a helpers the SAP cost path uses, so Bill Derivation's
day/night split matches the rating's exactly.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
modelling_e2e properties with main fuel 39 failed at the price boundary
(UnpricedFuelCode since #44fff767; previously mis-rated as non-electric →
the ~14-SAP over-rating flagged in earlier review).
Code 39 is SAP Table 12 "electricity, any tariff" (epc_codes.csv main_fuel 39 =
"electricity, unspecified tariff"; spec footnote (j): defines an electric system,
cost/CO2/PE = standard electricity). It was absent from API_FUEL_TO_TABLE_32, so
to_table_32_code(39) was None → is_electric_fuel_code(39) False and pricing
raised.
Fix: map API_FUEL_TO_TABLE_32[39] = 30 (standard electricity) — the canonical
place Khalim's fuel work added codes. One line makes classification, pricing,
CO2/PE and the billing carrier all agree (39 → 30 → ELECTRICITY).
Tests: to_table_32_code(39)==30, is_electric_fuel_code(39) True, price == standard
electricity, and the billing carrier resolves to ELECTRICITY. 0 corpus impact
(no lodged corpus cert uses 39); accuracy + mapper-corpus gates green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds the mapper-driven e2e cascade pin for "simulated case 50" (000565 semi,
electric storage main SAP 402 + portable electric secondary + MVHR + whc-903
DUAL electric immersion + 160 L cylinder, Economy-7). Routes the Summary PDF
through extractor + mapper + calculator like the other 000565 fixtures.
Locks in two off-peak fixes this case ground-truthed:
- the Table 13 HW high/low split applied to CO2/PE (commit 39ae2cf0), and
- the Table 12a Grid 2 MVHR fan fraction 0.71/0.58 (commit cd5113ab).
All 11 SAP-result fields reconcile to the U985 worksheet EXACTLY, including
the (272) rating CO2 2397.1237 — SAP 38.8426 (=39), cost £1317.0116, water
1668.0788 kWh, fans 315.6384 kWh.
Summary mirrored to the tracked fixtures dir so the test doesn't depend on
the unstaged `sap worksheets/` workspace.
pyright strict gate not run locally (pyright not installed in this container).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Table 12d/12e: electric water heating on a 7-/10-hour tariff bills
CO2/PE at the high-rate code (32/34) and low-rate code (31/33), kWh-weighted
by the Table 13 high-rate fraction. The cost path already applied this split;
the CO2/PE factors did not — they used the flat annual Table 12 figure
(0.136 CO2 / 1.501 PE) for ALL dual-rate electric HW.
That flat-annual behaviour (slice S0380.163) was validated only against
HW-from-main "low-rate cost" certs (100% low, no high-rate split). It is NOT
how Elmhurst bills a whc-903 ELECTRIC IMMERSION: the hand-built case-50
worksheet (000565 + dual immersion, 7-hour) splits HW CO2/PE into "high rate
cost" (CO2 0.1475 / PE 1.5514) + "low rate cost" (CO2 0.1238 / PE 1.4429)
weighted by the Table 13 fraction 0.1009. So flat-0.136 for immersion HW was
a spec gap on our side, not an Elmhurst divergence.
Fix: `_electric_immersion_hw_high_rate_fraction` threads the Table 13 fraction
(scoped to whc-903, 7-/10-hour, cylinder data present) into the HW CO2 + PE
factor helpers, which then blend the Table 12d/12e high/low codes. The flat
rule is unchanged for HW-from-main and 18-/24-hour (no Table 12d split), so
the S0380.163 41-variant cases and the existing pin are untouched.
Case 50: rating CO2 2413.48 -> 2397.1237 = Elmhurst EXACT; demand CO2 2007.1384
EXACT; demand PE +111 -> +32.5 residual (within corpus PE noise). Corpus
unchanged 73.3% / MAE 0.774 / CO2 0.08 / PE 3.4 (62 whc-903 off-peak certs;
aggregate gauges hold). SAP unaffected (cost-based).
Pin: test_whc903_immersion_hw_co2_pe_factors_split_high_low_on_off_peak; doc
updated in SAP_CALCULATOR.md §8.1.
pyright strict gate not run locally (pyright not installed in this container).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds the mapper-driven e2e cascade pin for "simulated case 52" (000565
semi + regular non-combi mains-gas boiler SAP 102 + 160 L foam cylinder
heated from the main, no cylinder stat, uninsulated primary pipework,
standard tariff). Routes the Summary PDF through extractor + mapper +
calculator like the other 000565 / 001431_case* fixtures.
This closes the last untested branch of the cylinder/water chain: the
SAP 10.2 §4 cylinder storage loss (Table 2/2a/2b lines 51-55) + the
Table 3 PRIMARY circuit loss (59, uninsulated pipework + no stat) that
combi/immersion fixtures don't reach. All 11 SAP-result fields reconcile
to the U985 worksheet EXACTLY with no calculator change — SAP 57.2904
(=57), cost £911.1973, water 3929.7635 kWh — confirming the cylinder-loss
derivation is correct.
Summary mirrored to the tracked fixtures dir so the test doesn't depend
on the unstaged `sap worksheets/` workspace.
pyright strict gate not run locally (pyright not installed in this container).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Table 12a Grid 2 (PDF p.191) bills "Fans for mechanical ventilation
systems" at 0.71 (7-hour) / 0.58 (10-hour), distinct from "All other uses"
(0.90 / 0.80) which covers circulation pumps, flue fans and the solar HW pump.
The cost-split mech-vent kWh (`mev_kwh_for_cost_split`) only summed the
decentralised-MEV (230b) fans, not the (230a) MVHR fan electricity — even
though the total pumps/fans bucket adds both. So an MVHR dwelling on an
off-peak tariff billed its fan electricity at the 0.90/0.80 "all other uses"
rate instead of 0.71/0.58. The comment already said "MEV/MVHR-fan portion";
only the MEV term was wired when MVHR landed. Fixed to mirror both
mechanical-ventilation fan terms summed into the total.
Worksheet-proven on simulated case 50 (000565 semi + MVHR Vent Axia + dual
electric immersion, Unknown meter -> 7-hour via the §12 dual-immersion
trigger): the fan bucket (315.64 kWh, 100% MVHR per worksheet line 230a) was
billing at 14.311 p/kWh (0.90) vs Elmhurst's 12.451 p/kWh (0.71) — +£5.87/yr,
-0.23 SAP. After the fix our existing-dwelling rating reconciles to Elmhurst
EXACTLY: SAP value 38.8426 (=Elmhurst 38.8426 -> 39), total cost £1317.0116
(=Elmhurst £1317.0116 to the penny).
Same `mev_kwh_for_cost_split` feeds the CO2 + PE cascades, so all three split
consistently. 0 corpus impact (all 3 corpus MVHR certs are standard tariff);
gauge unchanged 73.3% / MAE 0.774 / CO2 0.08 / PE 3.4.
Pin: test_mvhr_fan_electricity_bills_at_grid2_fan_fraction_on_off_peak.
pyright strict gate not run locally (pyright not installed in this container).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Table 4a electric boilers (PDF p.170) split across three distinct
Table 12a Grid 1 SH rows (PDF p.191), not one "direct-acting" family as the
stale TODO in `_table_12a_system_for_main` implied:
- 191 Direct-acting electric boiler -> "Direct-acting electric boiler (a)"
row: 7-hour 0.90, 10-hour 0.50 (NOT the 1.00/0.50 "Other direct-acting
electric heating" room-heater row).
- 193/194/195/196 Electric dry core / water storage boiler -> "Electric dry
core or water storage boiler" row: 7-hour 0.00 (charged wholly off-peak =
100% low rate, identical to the None fallback).
- 192 Electric CPSU -> Appendix F; left falling through to None (off-peak
low) until the Appendix-F high-rate cascade is implemented.
The enum + fractions already existed in table_12a.py; only the code->enum
mapping was missing. Resolves the TODO and pins the spec-correct 0.00 for the
storage boilers so 195 can't be mis-"fixed" up to a direct-acting fraction.
Forward guard, 0 corpus impact: storage boilers already billed 100% low via
the None fallback, and all corpus 191 certs are on standard tariff (Table 12a
off-peak split never fires). Corpus gauge unchanged 73.3% / MAE 0.774.
Pin: test_electric_boilers_191_195_map_to_distinct_table_12a_grid1_rows.
pyright strict gate not run locally (pyright not installed in this container).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Table 3a (PDF p.160) additional combi loss (61)m. Two coupled
defects, both surfaced by simulated case 49 (000565 + gas combi, U985
"Combi keep hot type = None") sitting at SAP 71.43 vs the worksheet's 72:
1. The cascade defaulted EVERY non-PCDB combi to the flat keep-hot
time-clock row (600 × n/365). A combi WITHOUT a keep-hot facility uses
row 1 (600 × fu × n/365, fu = V_d/100 when daily HW < 100 L/day) —
over-counting (61)m for the no-keep-hot cohort. `water_heating_from_
cert` now defaults to the "without keep-hot" row.
2. `pcdb_combi_loss_override` returned None for keep_hot_facility=1/
timer=1, leaning on the OLD flat-600 default. So flipping the default
silently turned 190 corpus PCDB keep-hot-time-clock combis into
no-keep-hot. Fixed to return the flat keep-hot row EXPLICITLY.
Key insight (the Summary is the input echo; the U985 keep-hot line is a
computed OUTPUT, so it must be derivable): keep-hot rides on the PCDB
boiler record (Table 105 keep_hot_facility/timer), resolved by
`pcdb_combi_loss_override`. A generic SAP-code combi with no PCDB record
(case 49, PCDF ref 0) has no keep-hot by construction → row 1. So the
default is not a guess — it is the spec-correct value for non-PCDB combis.
Worksheet-proven: case 49 → cost £726.696, SAP 72 — matching the
accredited worksheet to the digit (continuous 71.6945 = the worksheet's
own 71.6945). 000516 (keep-hot None) also exact (£860.716, SAP 63);
000490 (PCDB 10328, keep_hot_facility=1/timer=1) keeps its flat-600 via
the PCDB path. Masked until now because every prior combi-loss worksheet
fixture was keep-hot (000490/000474/000480 time-clock) or had V_d >= 100
every month (001431, rows coincide); case 49 is the first no-keep-hot one.
Corpus within-0.5 72.7% -> 73.3%, MAE 0.781 -> 0.774, PE 3.5 -> 3.4;
ratcheted _MAX_SAP_MAE 0.785 -> 0.775, _MAX_PE_PER_M2_MAE 3.6 -> 3.5.
Note: pyright strict type gate not run locally (pyright not installed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
MVHR (24a) heat-recovery support, part 2: the mapper + cascade wiring.
Both source paths now resolve balanced whole-house MV with heat recovery
to the MVHR kind:
- gov-API: `_API_MECHANICAL_VENTILATION_TO_KIND` 4 → "MVHR" (was None /
treated as natural — under-stated ventilation heat loss, over-rating).
- Elmhurst Summary: `_ELMHURST_MV_TYPE_TO_KIND` "Mechanical ventilation
with heat recovery (MVHR)" → "MVHR" (was UnmappedElmhurstLabel, which
blocked the whole Summary for MVHR dwellings).
cert_to_inputs resolves the in-use heat-recovery efficiency + SFP for an
MVHR cert (`_mvhr_system_values`): pick the PCDB Table 323 data point by
the lodged wet-room count (SAP 10.2 §2.6.4), multiply the raw efficiency
by the Table 329 ducts-inside-envelope in-use factor (0.90) and the raw
SFP by the per-duct-type factor (rigid 1.4), and feed:
- the §2.6.6 eq (2) effective-air-change credit (23c) → (24a)/(25)m;
- the (230a) fan electricity (in-use SFP × 1.22 × V), costed but NOT
added to the Table 5a gains (its effect is in the efficiency).
An MVHR lodged with no PCDF index falls back to the SAP 10.2 Table 4g
default (raw efficiency 66% × 0.70, raw SFP 2.0 × 2.5).
Worksheet-proven on simulated case 49 (000565 semi + Vent Axia Sentinel
Kinetic B 500140 + gas combi → Elmhurst Current SAP 72): every MVHR line
matches Elmhurst exactly — (33) fabric heat loss 100.5923, (23c) in-use
efficiency 81.9% = 91 × 0.90, (25)m Jan 0.8571, (230a) fan electricity
415.9325, (231) total pumps/fans 501.9325. The residual SAP 71 vs 72 is
the known 000565-family space-heating-demand artifact (same -1/-2 seen on
cases 47/48), not the MVHR logic.
Corpus: within-0.5 72.6% -> 72.7%, MAE 0.788 -> 0.782, PE 3.6 -> 3.5.
The 3 gov-API MVHR certs: Flat 1 +6 -> 0 (Table 4g default path) and
12a Princes Gate +3 -> +1 (heat-recovery credit); Apartment 707 -4 -> -6
is a separate baseline under-rate (it under-rated as natural too — the
MVHR credit correctly adds ventilation loss per Elmhurst's method).
Ratcheted _MAX_SAP_MAE 0.79 -> 0.785, _MAX_PE_PER_M2_MAE 3.7 -> 3.6.
Note: pyright strict type gate not run locally (pyright not installed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
MVHR (24a) heat-recovery support, part 1: the PCDB data layer.
PCDB Table 323 (PCDF Spec Rev 6b §A.18, Format 426; pcdb10.dat carries
Format 431, header `$323,431,...`) holds the per-wet-room SFP + heat-
exchanger efficiency for centralised MEV / MVHR units. Added
`MvhrRecord` / `MvhrDataPoint`, `parse_centralised_mv_row` /
`parse_table_323`, the ETL step, the committed jsonl, and the
`mvhr_record(pcdb_id)` runtime lookup (mirrors Table 322).
SAP 10.2 §2.6.4/§2.6.6: "MVHR ... SFP is a single value depending on the
number of wet rooms" — each test group's leading field is the wet-room
count; callers select the group matching the dwelling lodgement.
Worksheet-proven on simulated case 49 (000565, 2 wet rooms, Vent Axia
Sentinel Kinetic B 500140 → flow 21.0, SFP 0.88, efficiency 91%).
Also decoded the MVHR heat-recovery efficiency in-use factor from Table
329 (Format 432): system_type 3 ducts-inside-envelope = 0.90 (case-49
(23c) = 91 × 0.90 = 81.9%), cross-checked against system_type 10 = 0.70
(= SAP 10.2 Table 4g default heat-recovery in-use factor). "Table 4h is
no longer used – data now stored in the PCDB" (SAP 10.2 p.176).
The outside-envelope efficiency columns + with-scheme SFP blocks are
preserved verbatim in `raw` (no fixture exercises them yet).
Note: pyright strict type gate not run locally (pyright not installed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Corpus validation of the modelling_e2e photovoltaic_supply-as-list fix. Cert
6102-6227-8000-0083-2292 (RdSAP-20.0.0 semi, gas combi + 2× 1.14 kW PV arrays)
crashed from_rdsap_schema_20_0_0 on the measured-array list; the fix routes it
through the dict-tolerant _map_schema_21_pv. PV correctly credited: engine 61
(no PV) → 66 (+5). Built in Elmhurst (evidence: epc.json + summary + worksheet,
fabric+heating; the PV "New Technologies" Panel-details grid deferred): worksheet
55 = engine-on-Elmhurst-inputs 55 exactly → calculator faithful. The +6 engine-vs-
Elmhurst base-dwelling residual is the documented RdSAP-default gap (band-C cavity-
uninsulated suspended-floor semi). Pinned engine 66.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Corpus validation of the modelling_e2e built_form fix. Cert 8742-6624-9300-2780-4926
(SAP-Schema-16.0, ground-floor electric-storage-heater flat) omits built_form; the
mapper now derives it from dwelling_type. built_form is ML-only so the fix is
SAP-neutral: engine 66 = lodged 66 exactly. Built in Elmhurst (evidence: epc.json +
summary + worksheet): worksheet 54, engine-on-Elmhurst-inputs 53 ≈ 54 → calculator
faithful. The +12 engine-vs-Elmhurst is a build/input gap (cert size-1 small cylinder
unrepresentable in Elmhurst's Normal/110L-minimum entry → higher HW + reduced-field
16.0 defaults). Pinned engine 66.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Chasing the space-heating demand gap on "simulated case 48" (main 691 + Unknown
meter + 903 dual immersion): our SAP 55 vs Elmhurst 57. Every §10a cost line
already matched to the penny; the residual was demand — our space-heating
energy 3849.8 kWh vs Elmhurst 3513.8 (+9.6%). Traced through the worksheet: our
ventilation heat loss (38) ran ~35.5 W/K vs Elmhurst 27.76 — we were adding 20
m3/h of intermittent extract fans (the Table 5 age-band default) on a dwelling
with a decentralised mechanical extract (dMEV) system that lodges 0 fans.
SAP 10.2 §2 (PDF p.13): a whole-house mechanical EXTRACT system provides
extraction via the (23a) 0.5 system air-change rate; the lodged intermittent
extract-fan count (7a) is then explicit — a lodged 0 means 0 (the dMEV is the
ventilation), NOT "unknown". The Table 5 default is an unknown-fallback for
NATURALLY ventilated dwellings only, so it must not be substituted here.
Fix: for EXTRACT_OR_PIV_OUTSIDE, take vc.intermittent_fans as-is (no age-band
default). Worksheet-proven on two dMEV builds of cert 000565: "case 48" lodges
(7a)=0 -> our SAP 55 -> 57 EXACT; the original 000565 fixture lodges (7a)=2 and
keeps 2 (its e2e pins are unchanged). An earlier draft that forced fans=0 broke
000565 (which legitimately has 2) — corrected to "lodged as-is".
within-0.5 72.5% -> 72.6%, MAE 0.789 -> 0.788; CO2/PE unchanged. The fix also
reduces a systematic under-rating bias in the 21-cert dMEV cohort (median dSAP
-0.22 -> -0.08). Scoped to EXTRACT_OR_PIV_OUTSIDE; balanced MVHR/MV kinds left
untouched pending their own worksheet. SAP-schema regression
test_18_0_0 pin 80 -> 81 (closer to its lodged 84, same cause). Spec-pinned in
test_cert_to_inputs (dMEV-lodged-0 vs natural-default). pyright not installed
in this container -- strict type gate not run locally.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Closes the follow-up from 22fe4f41. RdSAP 10 §12's third Unknown-meter
exception bullet — "main heating is ground source or water source heat pump" —
was unimplemented. Add `_GROUND_OR_WATER_SOURCE_HEAT_PUMP_CODES` (Table 4a,
SAP 10.2 PDF p.176-177: ground 211/215/221/225 + warm-air 521/525; water
213/216/223/226 + warm-air 523/526) to the Unknown-meter off-peak triggers;
once dual, Rules 1-4 (Rule 3) resolve it to 10-hour.
AIR-source heat pumps (214/217/224/227, 524/527) are deliberately EXCLUDED —
the spec names only ground/water source. Verified the only Unknown-meter heat
pumps in the corpus are "3/10 Bedford House" (main 214 = AIR source), which
correctly KEEP STANDARD. 0 corpus certs carry a GSHP/WSHP on an Unknown meter,
so this is a spec-completeness forward guard (gauge unchanged 72.5% / 0.789),
same family as the Scotland-J wall / rafters-M roof 0-impact spec fixes.
Coverage gap noted in-code: a database-index heat pump without a 211/213-style
SAP code can't have its source type read from the code alone (rare).
Spec-pinned (test_unknown_meter_ground_or_water_source_heat_pump_triggers_off_
peak). Gates green: corpus 72.5%/0.789, batch worksheet 0 raised/0 diverge,
suite 2989 passed (2 known pre-existing fails). pyright not installed locally.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Supersedes the previous "verified non-fix" doc (3548f1f3): the spec DOES make
this a fix — Khalim was right that the Unknown-meter branch is driven by the
heating/water system, not a blanket STANDARD.
RdSAP 10 §12 (PDF p.62): "If the electricity meter is unknown, treat as single
meter EXCEPT where main heating OR WATER HEATING are intended to run off an
off-peak tariff (per systems listed in the text box above) ... If that results
in a dual meter, assign tariff per rules 1 to 4." The text-box off-peak systems
include DUAL ELECTRIC IMMERSION. Our `rdsap_tariff_for_cert` only triggered the
Unknown→off-peak exception on a storage/CPSU MAIN — it ignored the
dual-electric-immersion WATER-heating trigger, so an Unknown-meter dwelling
with a non-storage main (e.g. room heaters) + dual immersion was billed
STANDARD (13.19p flat) when it should be dual → Rules 1-4 on the main.
Fix: thread `water_is_off_peak_dual_immersion` (whc 903 + immersion lodged dual
via `_immersion_is_single is False`) into the Unknown-meter branch; when any
text-box trigger is present, resolve via the same Rules 1-4 dispatch (room
heaters → Rule 3 → 10-hour). Single-immersion / instantaneous (whc 909) certs
correctly stay STANDARD (no text-box system).
Worksheet-validated on "simulated case 48" (main 691 + Unknown meter + 903 dual
immersion): Elmhurst 10-Hour Off Peak, SAP 57; ours 45 → 55 (7-hour gives 45,
confirming 10-hour). Flips exactly ONE corpus cert — Apartment 241 (the genuine
-5.38 under-rater, main 691 + dual immersion) -5.38 → -1.05; every other
Unknown+dual-immersion cert already has a storage main (Rule 2). Corpus
within-0.5 holds 72.5%, MAE 0.793 → 0.789 (improved). CO2/PE unchanged.
GSHP/WSHP-main trigger (the other §12 Unknown exception bullet) is a separate
follow-up. Gates green: corpus 72.5%/0.789, batch worksheet 0 raised/0 diverge,
000565 e2e 11/11, suite 2987 passed (2 known pre-existing fails). pyright not
installed in this container — strict type gate not run locally.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Two second-main fuel errors mis-cost a dual-main dwelling whose two main systems
burn different fuels (SAP 10.2 §10a worksheet (213) bills main 2 at its own fuel):
1. Off-peak/legacy scalar cost path (calculator.py + cert_to_inputs.py): main 2's
kWh was priced at main 1's `space_heating_fuel_cost_gbp_per_kwh` scalar. Split
main 1 vs main 2 and price main 2 at its OWN rate via the new
`_main_2_space_heating_fuel_cost_gbp_per_kwh` (+ CalculatorInputs field).
Scoped to a NON-electric second main (wood/oil/coal) — an electric second
main keeps main 1's scalar (its off-peak Table 12a split is the deferred §10a
slice; per-system splitting it regresses the off-peak electric cohort, certs
13 Parkers Hill / 34 Dunley Road). 0 corpus impact (no corpus cert has a
non-electric second main on an off-peak meter).
2. Elmhurst Summary mapper (mapper.py): when §14.1 omits the Fuel Type cell, a
fuel-fired second main (room-heater SAP code) inherited main 1's fuel. Derive
it from the SAP code's Table 4a category (solid 631-636 -> house coal, gas ->
mains gas, liquid -> oil) before the main-1 inherit, mirroring
`_elmhurst_secondary_fuel_from_sap_code` (same modal sub-fuel caveat). Boiler
codes (<601) still inherit main 1 (case 6 oil rads+UFH).
simulated case 47 (electric room heaters + solid room heaters 633): our SAP
37.81 -> 55.09 vs Elmhurst current 57 (residual is the wood-vs-coal sub-fuel the
Summary export does not carry). Corpus unchanged 72.5% / MAE 0.793; batch 0
raised / 0 diverge; 000565 e2e green. (mapper.py also carries an earlier,
behaviour-free roof-window doc comment.) Spec-cited unit pins added (AAA).
pyright not installed locally — strict type gate not run.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
`table_32.unit_price_p_per_kwh` silently returned the mains-gas default
(3.48 p/kWh) for any fuel code it could not resolve to a Table 32 price or a
translatable gov-API enum. An unhandled fuel billed at the gas rate mis-costs
the dwelling (same failure mode as the dual-main wood-vs-electric over-cost).
Raise `UnpricedFuelCode` (new, mirrors MissingMainFuelType / UnmappedSapCode)
so the gap surfaces at the price boundary. `None` (no fuel lodged) still
defaults — callers resolve "no system" upstream.
0 corpus impact: all 1000 certs compute (every lodged fuel resolves), so this
is a forward guard against future/unmapped fuels. Unit pin added; existing
None-default test docstring tightened. pyright not installed locally — strict
type gate not run.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Main heating system 2's space-heating fuel cost (worksheet (213)) was billed
at main system 1's Table 32 unit price (`main_2_high_rate_gbp_per_kwh` reused
`main_1_high_rate_gbp_per_kwh`). For a dual-FUEL pair this grossly mis-costs the
second main: cert 10032957680 "Copse Cottage" (main 1 electric room heaters
fuel 30, main 2 wood logs fuel 6) charged its 9481 kWh of wood at 13.19 p/kWh
instead of 4.23 p/kWh — +£850/yr → SAP 21.75 vs lodged 45.
Route main 2 through its own fuel code (`_main_fuel_code(details[1])`), mirroring
the existing secondary-fuel handling. Copse Cottage 21.75 -> 45.94. Corpus
within-0.5 holds 72.5%, SAP MAE 0.815 -> 0.793 (ratcheted ceiling 0.82 -> 0.80);
CO2/PE unchanged. Same-fuel dual mains (gas+gas) unaffected. Off-peak-tariff
dual-fuel mains still defer to the legacy scalar path (separate slice).
Spec-cited unit pin added (AAA). pyright not installed locally — strict type
gate not run.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Table 5 reads "Number of extract fans if known; if number is unknown:
[age-band default]" — the default is an UNKNOWN-fallback, NOT a floor. The
cascade applied `max(lodged, table_5_default)`, flooring a genuinely-lodged
count up to the age-band minimum: e.g. an age H-M dwelling lodging 2 extract
fans was billed at the 6-8-room default of 3, over-counting ventilation line
(8) and the heat-loss coefficient. Fixed to `lodged if lodged > 0 else
default` (a lodged 0 is the Elmhurst/RdSAP "unknown" form → default; any
positive count is taken literally).
Surfaced by Khalim's Elmhurst stress worksheet (simulated case 46): this was
its last ventilation residual — our Jan effective ACH 9.14 -> 9.0748 (exact
match to the accredited worksheet), SAP 29 -> 30 = Elmhurst, cost £1496 vs
£1493. Corpus IMPROVED: within-0.5 71.6% -> 72.5%, MAE 0.819 -> 0.815 (the
max-flooring over-counted ventilation on every cert lodging fans below its
age default). Floor ratcheted 0.71 -> 0.72. pyright not installed locally.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
When the main heating system does not heat every habitable room (heated rooms
< habitable rooms), SAP 10.2 Appendix A.2.2 assumes the unheated rooms are
served by a portable-electric secondary heater, so the Table 11 secondary
fraction (0.10 for a boiler main) must be costed at the electricity tariff —
even when the cert lodges no explicit secondary system.
`_secondary_fraction` previously returned 0 unless a secondary was lodged or
the main was a forced-secondary electric-storage code, dropping the assumed
secondary and billing 100% of space heat to the (cheaper) main fuel — an
over-rate. Added an `unheated_habitable_rooms` trigger plus
`_has_unheated_habitable_rooms(epc)`, which prefers the lodged
`any_unheated_rooms` flag and guards the gov-API `heated_rooms_count == 0`
"not provided" sentinel. The secondary fuel/efficiency cascade already
defaults to portable electric (code 693) when no secondary code is lodged.
Worksheet-validated on simulated case 46 (heated 4 < habitable 7, no lodged
secondary): the assumed 10% electric secondary (2289 kWh, ~£260) lifted our
SAP 39 -> 29.35 vs accredited Elmhurst 30 (cost £1502 vs £1493, within 0.6%).
Corpus UNCHANGED (71.6% / MAE 0.819): all 17 corpus certs with heated <
habitable already lodge an explicit secondary description, so the gov-API
path was already costing it; this only adds the assumed secondary where none
is lodged (Elmhurst / reduced-field path). pyright not installed locally.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The SAP rating is spec-floored at 1 ("if the result of the calculation is
less than 1, the rating is 1"). `sap_rating_integer` already clamps, but the
continuous `sap_score_continuous` did not — so a degenerate dwelling could
emit a physically impossible negative SAP. Apply the same max(1, …) floor to
the continuous value (the un-rounded part is for sensitivity near real
ratings, not for negative ratings).
Removes a -12.3 accuracy outlier on the committed corpus (cert 422000111926,
lodged at the floor of 1, was computing -11.3): within-0.5 70.2% -> 70.3%,
MAE 0.845 -> 0.833. Ratcheted the corpus MAE ceiling to 0.84. Unit-pinned in
test_calculator.
pyright not installed in this codespace (strict gate not run locally).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The gov-API lodges secondary fuel as an enum whose value can COLLIDE with a
different same-valued RdSAP 10 Table 32 / SAP 10.2 Table 12 fuel code:
- enum 9 = "dual fuel (mineral and wood)" vs Table code 9 = LPG SC11F
- enum 5 = "anthracite" vs Table code 5 = LPG (bulk)
The main-fuel boundary already canonicalises these (`_GOV_API_COLLISION_
FUELS`), but the SECONDARY-heating cost + CO2/PE paths never did — they took
the bare same-value lookup, so a dual-fuel room heater was priced as LPG
(3.48 vs dual-fuel 3.99 p/kWh) and emitted as LPG (CO2 0.241 vs 0.087),
and an anthracite secondary as bulk LPG (12.19 vs 3.64 p/kWh). The price
under-count over-rates SAP; the CO2 over-count inflates emissions.
Fix: add enum 9 to `_GOV_API_COLLISION_FUELS` (5 and 33 were already there)
and canonicalise the secondary fuel code on both the cost
(`_secondary_fuel_cost_gbp_per_kwh`) and factor (`_secondary_fuel_code`)
paths, mirroring the main-fuel boundary. canonical_fuel_code only touches
{5,9,33}, so genuinely Table-coded secondaries (House coal 11, wood logs 20,
community fuels 30-32) are left unchanged — confirmed by a full-map audit.
Corpus: within-0.5 69.7% -> 70.2% (MAE 0.854 -> 0.845; dual-fuel-secondary
cohort 42.9% -> 49.0%, signed +0.55 -> +0.41) and CO2 MAE 0.12 -> 0.08 t/yr
(bias +0.04 -> 0.00). Ratcheted the corpus floors (within 0.70, MAE 0.85,
CO2 0.09, PE 4.0). A prior session deferred enum 9 ("direction not
understood") while the EPC PE/CO2 lens was confounded by the climate-cascade
bug (fc7c4d2d); on the corrected lens the over-rate direction is clear.
pyright not installed in this codespace (strict gate not run locally).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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>
When a heat-pump cert lodges a PCDB Table 362 record, the APM override
set BOTH the space efficiency (N3.6) and the water efficiency (N3.7a)
from the heat pump unconditionally. But the PCDB η_water applies only
when the DHW is heated BY the heat pump (water-heating code "from main":
901/902/914). A separate electric immersion (WHC 903) heats the water at
100% regardless of the space system, so applying the HP's water SCOP
(187.5% × 0.6 in-use = 112.5%) under-counted the immersion's hot-water
fuel.
Gate the η_water override on the DHW-from-main codes; a separate immersion
keeps its own 100% efficiency. Space η_space still always uses the APM
value (the heat pump is the space main).
Worksheet-validated to 1e-4 on simulated case 45 (HP space + WHC-903
immersion): water fuel (62) 1893.57 -> 2130.2639, total cost (255)
619.7433, CO2 692.13 — all matching the P960 exactly; SAP 60.53 -> rounds
to the worksheet's 61. RdSAP-21.0.1 corpus unchanged (no HP+WHC903 certs
in it). Pinned in test_cert_to_inputs (immersion fuel is main-independent).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The flat floor-exposure heuristic keys on dwelling_type: a flat defaults
to has_exposed_floor=False (assuming a heated dwelling below). The
Elmhurst Summary path lodges a ground-floor flat's vertical position as a
"Ground floor" floor_type rather than the API floor_heat_loss=1 exposed
code, and the mapper can label such a flat "Top-floor flat" — so the
cascade dropped the ground floor entirely (a ground floor is in contact
with the ground and carries heat loss).
Treat a "ground floor" floor_type as a heat-loss floor, overriding the
dwelling-level suppression upward — mirroring the existing "another
dwelling below" party override downward.
Worksheet-validated to 1e-4 on simulated case 45 (a ground-floor flat
the mapper labelled "Top-floor flat"): floor (28a) 0 -> 25.38 W/K,
fabric (33) 75.63 -> 101.0104, HTC (39) 112.93 -> 145.3579, all matching
the P960 exactly; SAP 67.81 -> 62.52. RdSAP-21.0.1 corpus within-0.5
69.5% -> 69.7% (MAE 0.859 -> 0.854). Floors ratcheted. Pinned in
test_heat_transmission (ground-floor billed + party-floor suppressed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
