SAP 10.2 Table 3 (PDF p.160) row 1: primary circuit loss applies when
"hot water is heated by a heat generator (e.g. boiler) connected to a
hot water storage vessel via insulated or uninsulated pipes". The Table
4a hot-water-only codes (PDF p.166) 911 gas / 912 liquid / 913 solid
boiler-circulator + 921-931 range cooker with boiler are each a heat
generator feeding the cylinder through a primary loop.
`_primary_loss_applies` keyed only off the resolved DHW `main` — but for
these certs `_water_heating_main` returns the SPACE main (e.g. electric
storage heaters, SAP code 402, which has no primary loop), so every
boiler branch missed the gas water-boiler's primary circuit and (59)m
went to zero. New branch keys off `water_heating_code` ∈
`_WATER_HEATING_BOILER_CIRCULATOR_CODES`. 941 (electric HP for water
only) is excluded — HP DHW vessels follow the Table 3 integral-vessel
rules.
Simulated case 19 (electric storage main + WHS 911 + 210 L cylinder):
(62)m total HW demand 2493.30 → 3169.98 kWh/yr, matching the worksheet
(the missing 676.68 kWh/yr = the worksheet's (59) primary-loss annual
sum, h=5/p=0). The remaining (64)/(219) gap is the PV diverter (63b),
deferred to its own slice.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Reference the calculator-side wall_construction=6 disambiguation issue from the
strict-xfail tripwire and ADR-0019, so the blocker is traceable both ways.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Pin the resolution reached in the grill: planning status persists as a
per-UPRN write-through cache in the existing `property_details_spatial` table
(not FE-property columns), read back off the Property in Modelling; unknown
UPRN defaults to unrestricted, matching legacy `empty_spatial_df` (superseding
the earlier "conservative stance" note).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
System-built (precast/no-fines concrete) takes both solid-wall Options like
solid brick (ADR-0019), keyed on `wall_construction == 6` (WALL_SYSTEM_BUILT,
Elmhurst `SY`). A basement-suitability guard (`main_wall_is_basement`) is added
since a below-ground basement wall is never EWI/IWI-suitable.
This is currently inert: `B Basement wall` also maps to 6 (mapper.py:2100) and
`main_wall_is_basement` is derived as `wall_construction == 6`, so every code-6
wall reads as basement and is guarded out — the live cohort is unchanged. The
system-built EWI/IWI cascade pin is committed as a strict-xfail tripwire that
flips green the moment the calculator disambiguates system-built from basement
(MAIN wall_construction==6 with main_wall_is_basement False). `wall_construction
== 8` is Park home, not system-built — not keyed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Table 12a Grid 1 (PDF p.191): secondary heating is a direct-
acting electric room heater (RdSAP 10 §A.2.2 default), on the "Other
systems including direct-acting electric" row — 7-hour high-rate fraction
1.00, 10-hour 0.50. A room heater runs on demand, mostly at the high
rate; it does NOT earn the 100%-low-rate of overnight storage charging.
`_secondary_fuel_cost_gbp_per_kwh` previously returned the flat off-peak
LOW rate (5.50 p, £0.0550) for every off-peak electric secondary, under-
charging by 9.79 p/kWh. New `_secondary_off_peak_rate_gbp_per_kwh` mirrors
`_space_heating_fuel_cost_gbp_per_kwh`: it blends the Table 12a high-rate
fraction (OTHER_DIRECT_ACTING_ELECTRIC) against the Table 32 high/low
rates, with the 18-/24-hour fallback to the low rate.
Simulated case 19 (electric storage main + electric secondary, Dual/7-hour
meter) is the worksheet case (242): "Space heating - secondary
(1.00*15.29 + 0.00*5.50)" → 15.29 p/kWh = £0.1529. This was the primary
cat-7-cluster cost driver: total cost 1485.68 → 1835.53 (worksheet
1816.58), SAP cont 60.11 → 50.67 (worksheet ~51.22). Remaining +19 cost
is HW/space-heating kWh (next slices).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.6. The integrating proof through real Postgres: two solid-brick
uninsulated dwellings, identical but for the planning status Ingestion caches
per UPRN. Ingestion writes the spatial reference; Modelling reads it back off
the Property and gates the wall measures — the listed dwelling gets neither
EWI nor IWI, the unrestricted one gets a wall measure. Closes slice 3c
(ADR-0019/ADR-0020).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Table 2b note b (PDF p.159) applies the ×0.9 temperature-factor
reduction only when DHW is "separately timed" relative to space heating
on a SHARED heat generator ("boiler systems, warm air systems and heat
pump systems"). Per RdSAP 10 §10.5.1 (PDF p.55) a separate boiler/
circulator providing DHW only (water-heating code 911 = "Gas boiler/
circulator for water heating only") is NOT the main space-heating system
— so there is no shared timer to apply the ×0.9 against. `_separately_
timed_dhw` now returns False when water_heating_code is not "from main /
2nd-main system" ({901,902,914}), mirroring the existing WHC 903 electric-
immersion carve-out.
Simulated case 19 (electric storage main SAP 402 + WHS 911 + 210 L
loose-jacket cylinder) is the worksheet case. The single flag drives both:
- (53) Temperature factor: 0.54 → 0.6000 (worksheet base, no ×0.9)
- (55) storage loss/day: → 3.4531; (56)/(57)m Jan → 107.0456 (1e-4)
- (59)m primary loss: h=3 (43.31) → h=5 (Jan 64.5792), worksheet-exact
This also worksheet-pins S0380.224's loose-jacket storage loss magnitude
at 1e-4, previously only direction-validated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.5. `PropertyPostgresRepository` takes an injected `SpatialRepository`
and hydrates `Property.planning_restrictions` by UPRN (bulk in `get_many`,
single in `get`). A UPRN with no cached row — or a property with no UPRN —
defaults to unrestricted, matching legacy `empty_spatial_df` (ADR-0020). This
closes the loop: Ingestion caches the protections, Modelling reads them off the
Property to gate solid-wall EWI/IWI (ADR-0019).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.4. Ingestion now resolves the whole spatial reference in one lookup
(`spatial_for`) — the coordinates drive the Solar fetch as before, and the
reference (coordinates + planning protections) is persisted per-UPRN via
`uow.spatial` in the same write batch, so Modelling can read the protections
back off the Property (ADR-0020). `_Fetched` carries the UPRN and the reference
into the write phase.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.3. Ingestion writes the OS spatial reference cache through the same
unit it persists the EPC/solar enrichments with, so `UnitOfWork` declares a
`spatial` repo, `PostgresUnitOfWork` binds a `SpatialPostgresRepository` to the
session, and `FakeUnitOfWork` gains a `FakeSpatialRepo` (seedable for read
tests, recording writes for ingestion-side assertions).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.2. The OS Open-UPRN reference set is too large to host in Postgres, so
it lives in S3 and is cached per-UPRN in the existing `property_details_spatial`
table (ADR-0020). `PropertyDetailsSpatialRow` mirrors that table (uprn unique);
`SpatialRepository` / `SpatialPostgresRepository` upsert one shared row per UPRN
and read the planning protections back by UPRN (a null flag reads as
unrestricted; absent UPRNs are omitted so the caller defaults them).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Bump HEAD/next-slice/baseline, note the committed scripts toolkit, and add
the active "simulated case 19" section: the electric-storage-heater +
loose-jacket worksheet the user generated, what S0380.226 unblocked, and
the prioritised cluster bugs it exposed (cost (255) -334 = the +9 SAP
driver; Table 2b TF x0.9; WHS-911 storage-vs-combi routing; fabric +1.0).
Updated the "what to generate" ask to the two highest-value follow-ups
(electric room heaters; Sheltered/Adjacent RR gables).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3c.1. Ingestion will persist a UPRN's coordinates and planning
protections together as a write-through cache, so resolve them in a single
partition read rather than two. `SpatialReference` bundles the coordinates
(which drive the Solar fetch) and the `PlanningRestrictions` (which gate wall
insulation per ADR-0019/ADR-0020); `GeospatialRepository.spatial_for(uprn)`
returns it, and `coordinates_for`/`planning_restrictions_for` now delegate to
the one lookup.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The Summary-path mapper raised UnmappedElmhurstLabel for a §15.1
"Cylinder Insulation Type: Jacket" lodging — only "Foam" (→1, factory)
was mapped. SAP10 cylinder_insulation_type uses 2 for loose jacket
(matching the GOV.UK API codes), and SAP 10.2 Table 2 Note 1 gives it a
separate ~2× storage-loss factor that the cascade now handles
(S0380.224). Add "Jacket" → 2 for cross-mapper parity with the API path
and so the loose-jacket storage-loss branch fires on the Summary path.
Surfaced by simulated case 19 (a 210 L jacket cylinder + electric storage
heaters), which previously couldn't extract at all. §4 suite 2397 passed;
mapper.py pyright unchanged at 32.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Three reusable scripts (each with a purpose/usage docstring) for wide-scale
testing of the calculator's API front-end against the GOV.UK EPB register —
the toolkit behind the 1000-cert study (docs/HANDOVER_API_SAMPLE_ACCURACY.md):
fetch_2026_epc_sample.py — sample cert numbers across a date window
(random pages) + download full schema-21 JSON
to a cache; resumable, 429/5xx backoff.
eval_api_sap_accuracy.py — % within 0.5 SAP, error histogram, worst-40,
and the mapper/calculator raise breakdown.
analyse_api_sap_clusters.py — error grouped by property + heating type to
locate clusters (electric heating, flats, PV).
Cache dir defaults to /tmp/epc_2026_sample, overridable via EPC_SAMPLE_CACHE.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Captures the wide-scale 2026-register study (41.8% <0.5, heating-driven
cluster table), the 7 slices shipped (S0380.219-225), the prioritised
remaining work (electric-heating clusters + worksheet-backed raises), and
the single highest-ROI worksheet to generate: an electric-storage-heater
house with a loose-jacket cylinder + a room-in-roof with Sheltered/
Adjacent gables + an extension — one document that validates the #1
accuracy cluster, pins the S0380.224 loose-jacket fix at 1e-4, closes the
gable_wall_type Table 4 raise, and exercises multi-bp fabric.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3b+3d (ADR-0019/0020). Property gains a planning_restrictions attribute
(default unrestricted); the ModellingOrchestrator threads it from the Property
through _plan_for -> _scored_candidate_groups -> _candidate_recommendations into
recommend_solid_wall, replacing the unrestricted default. run_modelling exposes
a planning_restrictions param so the offline harness can inspect restricted
properties. Integration test: a listed solid-brick dwelling that gets IWI when
unrestricted now yields no wall insulation. 145 tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The §10.7 no-water-heating default cylinder raised UnmappedSapCode for
age bands A-F (2 certs in a 2026 sample, bands B + C) because Table 29's
"A to F: 12 mm loose jacket" row wasn't plumbed — the loose-jacket
storage-loss branch didn't exist. S0380.224 added it, so this slice
completes the Table 29 lookup.
Restructure _TABLE_29_DEFAULT_CYLINDER_INSULATION_BY_AGE to carry
(cylinder_insulation_type, thickness_mm) per band — A-F → (loose jacket,
12), G/H → (factory, 25), I-M → (factory, 38) per RdSAP 10 Table 29
(PDF p.56) — and have the default read both, setting the loose-jacket
type for A-F instead of hardcoding factory. The strict-raise is retained
only for an absent / out-of-A-M age band (no Table 29 row).
Validated: certs 2211 (band B, SAP 49.8 vs lodged 52) and 3420 (band C,
11.2 vs 11) now compute. §4 + golden suite 2395 passed — the corpus
"no system" cert (age G, 25 mm factory) is unchanged. cert_to_inputs.py
pyright unchanged at 32; new test suppresses reportPrivateUsage.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3a (ADR-0020). PlanningRestrictions relocated out of the solid-wall
generator into domain/geospatial/ as the shared, Property-level value object
(three distinct flags + measure-specific blocks_external/blocks_internal).
GeospatialRepository gains a non-abstract planning_restrictions_for defaulting
to None (sources without the flags need not implement it); GeospatialS3Repository
reads conservation_status/is_listed_building/is_heritage_building from the same
Open-UPRN partition as the coordinates (legacy column names — to confirm in the
S3 deep-dive). Shared _row_for helper dedups the partition lookup.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_cylinder_storage_loss_override` returned None for any cylinder whose
cylinder_insulation_type wasn't 1 (factory), so a loose-jacket cylinder
(code 2, RdSAP 10 field 7-11) fell to the cascade's zero-storage-loss
combi/instantaneous default — its real storage loss vanished. SAP 10.2
Table 2 Note 1 gives loose jacket a SEPARATE, ~2× higher loss factor
(L = 0.005 + 1.76/(t+12.8) vs factory 0.005 + 0.55/(t+4)); the
cylinder_storage_loss_factor_table_2 helper already implements it — only
the dispatch was missing.
Fix: a `_cylinder_storage_loss_insulation_label` resolver maps the lodged
code to the Table 2 branch (1 → factory_insulated, 2 → loose_jacket;
None/0/unknown → None, keeping the conservative no-loss default). The
override and the HW storage call now route through it instead of
hardcoding "factory_insulated".
Evidence + validation: a random 2026 register sample has 22 loose-jacket
certs that over-predicted SAP by +2.29 mean (18/22 too high, 1/22 within
0.5) — the exact signature of under-counted HW storage loss. After the
fix their mean error collapses to +0.45 and 11/22 land within 0.5, with
ZERO regression across the worksheet-validated cohort (§4 + golden suite
2394 passed — no validated cert lodges loose jacket, so none shifts).
Also unblocks the §10.7 A-F no-water-heating default (next slice) which
needs the loose-jacket branch. cert_to_inputs.py pyright unchanged at 32.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2e. recommend_solid_wall joins the orchestrator's fabric generator pool
(restrictions default unrestricted until slice 3 sources them); the harness
catalogue + contingencies (26%) gain external_wall_insulation /
internal_wall_insulation. run_modelling on an uninsulated solid-brick dwelling
(baseline SAP 36.6) now selects internal wall insulation into the optimised
package; the catalogue-completeness guard covers both new measure types.
Golden cohort 57/57 still error-free; IWI now fires on a real cohort cert.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2d. A flat can take IWI (its own unit) but not EWI (whole-block
coordination) — ADR-0019. _is_flat handles both ingestion representations:
the Elmhurst name form ('Flat') and the API stringified RdSAP code ('2' = Flat
per PROPERTY_TYPE_LOOKUP). Completes slice 2's eligibility surface.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2c. recommend_solid_wall takes a PlanningRestrictions value object
(defaults unrestricted): a conservation area removes the EWI Option (external
appearance), a listed or heritage building removes both EWI and IWI (protected
fabric) -> None when nothing survives (ADR-0019). Plus a guard that a cavity
wall yields no solid-wall Recommendation (it is handled by recommend_cavity
_wall). PlanningRestrictions will be sourced onto the Property from the
geospatial layer in slice 3 (ADR-0020).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Summary PDFs preprocessed from `pdftotext -layout` wrap the windows-table
header across several lines. The third header line's tail ("U value / g
value / Draught Proofed / Permanent Shutters") tokenises to "value value
Proofed Shutters" and lands directly above the FIRST window's data row.
Because the first window in a building part has `before_start = 0`, its
prefix block reaches back into that header remnant. The remnant is
neither an orientation nor a building-part fragment, so it survived the
pops in `_compose_window_descriptors` and leaked into glazing_type as
"value value Proofed Shutters Double between 2002 and 2021" (windows 2-3,
whose prefix starts after the previous window's manufacturer line, were
clean).
Fix: the glazing-type phrase always starts with a glazing-start word
(Single/Double/Triple/Secondary), so trim any prefix fragments preceding
that word before joining the glazing type. Orientation/bp pops still run
on the full prefix, so they are unaffected.
Reproduced from `sap worksheets/Recommendations Elmhurst Files/
cavity_wall_insulation - main wall/before/Summary_001431.pdf`. Added a
regression test driving the real `_extract_windows_from_layout` path with
the verbatim tokenised header+rows. 2306 passed (+4), pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adds the user-simulated 001431 case (the cert that drove S0380.189/.190)
as an Elmhurst-only e2e fixture: Summary PDF → extractor → mapper →
calculator, every Block-1 SapResult field pinned against the
P960-0001-001431 worksheet at abs=1e-4. All 11 pins pass with zero
residual — the case is clean, confirming the S0380.190 gas-combi fuel
derivation closes the Summary path natively.
Verified the handover's flagged "+0.0007 SAP" was a target artifact, not
a cascade gap: the worksheet displays ECF (257) rounded to 1.6047 and
integer SAP (258)=78; the cascade's continuous SAP is computed from the
UNROUNDED ECF = (255)*(256)/((4)+45) = 660.9750*0.4200/173.0, giving
77.6147 — which matches the worksheet's own unrounded value. Pinning the
continuous SAP from the display-rounded ECF (→ 77.6144) was the wrong
target. Block-1 line refs all match exactly: (211) 10699.7225, (219)
3327.1592, (231) 86.0, (232) 283.2229, (255) 660.9750, (272) 3000.1664,
Σ(98) 8987.7669.
Summary mirrored into the tracked fixtures dir as
Summary_001431_gas_combi.pdf (distinct name — the corpus reuses cert
001431 across every heating variant); source Summary + worksheet tracked
under sap worksheets/golden fixture debugging/ as the pin ground truth.
2302 passed (+11), 0 failed; pyright net-zero on new/changed files.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The newer Elmhurst Summary export lodges a gas combi as §14.0 "Fuel Type"
empty + "Main Heating SAP Code" 104 (EES "BGW"), with no fuel string. The
site-notes mapper left `main_fuel_type=''`, so `cert_to_inputs` raised
`MissingMainFuelType` — blocking the whole gas-combi Summary path
(reproduced on the simulated 001431 case).
SAP 10.2 Table 4b (PDF p.168) rows 101-119 are "Gas boilers (including
mains gas, LPG and biogas)": the code fixes the boiler type/efficiency but
NOT the carrier, so 104 alone can't distinguish mains gas from LPG. The
disambiguator is §15.0 "Water Heating Fuel Type" — a combi/boiler heats
space + water from one appliance — exactly mirroring the existing
liquid-fuel (codes 120-141) fallback. `_elmhurst_gas_boiler_main_fuel`
adopts the §15.0 carrier only when the SAP code is in 101-119 AND §15.0
resolves to a gas/LPG fuel, so a regular boiler + electric immersion
(§15.0 = "Electricity") still strict-raises rather than mis-billing gas
as electric.
2291 passed (+1), 0 failed; pyright net-zero on both files.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Point-in-time note for the next agent: what S0380.185-189 shipped (worksheet
PE/CO2 pins, the two D_PV electricity-vs-gain fixes, and the thermal-mass-
parameter Table 22 fix), the per-line diagnosis template, the two worksheet-
block / gains-vs-solar traps, and the ranked open slices (Summary-path fuel
derivation first, then pin the simulated 001431 case, then cert 6035).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The §7 mean-internal-temperature cascade hardcoded the thermal mass parameter
(TMP) to 250 kJ/m²K at all 5 call sites, ignoring construction. RdSAP 10
§5.16 Table 22 (PDF p.48) makes TMP construction-dependent:
100 kJ/m²K — timber frame, cob, park home (regardless of internal
insulation); OR masonry (stone/solid brick/cavity/system
built) WITH internal insulation.
250 kJ/m²K — masonry WITHOUT internal insulation.
A too-high TMP inflates the §7 time constant τ = Cm/(3.6·H) (e.g. 40 h vs
16 h), under-cuts the temperature reduction between heating periods, and
over-states mean internal temperature → over-states space heating.
`_thermal_mass_parameter_kj_per_m2_k(epc)` classifies the MAIN building's
wall via the RdSAP `wall_construction` codes (5/7/8 = timber/cob/park) and
`wall_insulation_type` codes (3/7 = internal); unknown/curtain fall back to
the masonry 250 (no regression on unlisted classes). 17-case parametrised
test covers every Table 22 branch.
Diagnosis (per-line walk vs the user-simulated 001431 worksheet, same
archetype as golden cert 6035): fabric (26-37), internal gains (73), climate
(96)m and HTC (39) all EXACT; the entire +8.78 PE / -1.76 SAP gap was §7 MIT
(92) +0.71 °C, traced to TMP 250 vs Table 22's 100 (solid brick WITH internal
insulation). Fix closes the simulated case to 1e-4 on PE and CO2.
Blast radius: only golden cert 6035 re-pins (solid brick + internal
insulation) — SAP resid -6 → -2, PE +46.42 → +19.16, CO2 +1.07 → +0.42. The
47 dr87 cohort, 6 U985 fixtures and 41-variant heating corpus are all
masonry-no-internal → TMP unchanged at 250, all still pass. 2290 pass
(+17 new), 0 fail; pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A single durable doc so agents can pick up the calculator without reading
historical handovers: (1) the accuracy bar for the two input paths
(site-notes 1e-4 vs worksheet; API 1e-4 when a worksheet exists, ±0.5
register fallback otherwise; cross-mapper parity); (2) the per-line-walk
debugging loop incl. comparing site-notes vs API; (3) the tools &
pipeline (Summary PDF → extractor → from_elmhurst_site_notes →
cert_to_inputs → calculate_sap_from_inputs → SapResult, plus the API
from_api_response front-end, section helpers, and where the test vectors
live). Pointer added from SAP_CALCULATOR.md; HANDOVER_* flagged as
point-in-time notes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Appendix M1 §3a (p.93) defines PV-eligible demand as
D_PV,m = E_L,m + E_A,m + E_cook,m + E_ES,m + (231)·n_m/365 + E_space,m + E_water,m
where E_L,m is the lighting ELECTRICITY (Appendix L eq L10, = line (232)).
The cascade fed `internal_gains_result.lighting_monthly_w` — the L12 internal
heat GAIN G_L,m = E_L,m × 0.85 ("assuming 15%" of lighting energy does not
become internal heat) — into D_PV, understating it by 15% of lighting on
every PV cert. That depressed the monthly β onsite/export split and
under-credited PV primary energy uniformly across the year.
Same gain-vs-electricity class as the cooking fix S0380.73 (L18 gain vs L20
electricity). Fix: scale the (shape-identical) lighting gain profile to the
annual E_L `lighting_kwh_per_yr` (= (232)), mirroring the (219)m hot-water
scale-to-annual. Magnitude-only, so the shape-weighted lighting CO2/PE
effective factor (Σkwh×f/Σkwh, magnitude-invariant) is unchanged; appliances
need no scaling (G_A = E_A, no 0.85). Diagnosis was empirical first (calc
lighting D_PV 95.1 vs worksheet (232) 111.88, ratio exactly 0.85) then
confirmed against the spec text (L9d/L10/L12, M1 §3a).
Impact (calc − full-precision dr87 worksheet): ALL 47 worksheet certs now
match at <1e-4 on BOTH PE (max |Δ| 0.0000 kWh/m²) and CO2 (max |Δ| 0.0000 kg)
— the convergence target, met cohort-wide. Combined with S0380.187 this
closes the entire gas+PV + ASHP PV residual. Re-pinned 47 worksheet residuals
to 0.0000 and 31 drifted lodged residuals (PV certs). SAP integers unchanged;
chain SAP 1e-4 intact (164 pass). 2273 pass, 0 regressions; pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The PV onsite/export β-split (SAP 10.2 Appendix M1 §3a, p.93) divides PV
generation by the monthly PV-eligible electricity demand D_PV,m. The cascade
included main and water electricity (when those fuels are electric) but had
no term for SECONDARY space heating. For the 10 cohort-2 gas-main +
electric-secondary + PV certs, the (215)m secondary electric fuel was dropped
from D_PV,m — understating demand in the heating months only, depressing the
monthly β, and under-crediting onsite PV primary energy.
Spec: Appendix M1 §3a counts E_space,m as the dwelling's TOTAL electric
space-heating demand; for a gas-main/electric-secondary dwelling that is the
secondary fuel. Diagnosis was decisive: E_PV (generation) matched the
worksheet exactly every month, the onsite (233a) split diverged ONLY in
heating months (Jun-Sep near-exact), and all 10 affected certs have PV while
all clean gas certs have none. Empirically adding (215)m to D_PV closed cert
3136 onsite 726.9 → 790.3 (worksheet 792.1).
Impact (calc − full-precision dr87 worksheet), the 10 certs:
PE +0.5..+1.5 → +0.02..+0.046 kWh/m²; CO2 −0.5..−1.1 → +0.002..+0.0095 kg.
The whole 47-cert cohort now matches at PE <0.05 / CO2 <0.025. SAP integers
unchanged; chain SAP 1e-4 pins intact (164 pass). The uniform ~0.03 PE remnant
on PV certs is the separate (233a)/(233b) summer-month D_PV discrepancy.
Re-pinned the 10 worksheet + 9 lodged golden residuals (improvements).
2273 pass, 0 regressions; pyright net-zero (file's 32 errors pre-existing).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The existing golden test compares calc PE/CO2 against the integer-rounded
lodged register values (energy_consumption_current / co2_emissions_current),
which conflates real calculator gaps with register rounding. This adds a
parallel pin against each cert's Elmhurst dr87 worksheet (286)/(272) at full
precision — a clean calculator-vs-Elmhurst signal for the 47 worksheet-backed
certs (9 ASHP + 38 cohort-2).
Findings at capture (calc − worksheet, on the worksheet's own decimal TFA):
- 37/47 exact on both PE (<0.05 kWh/m²) and CO2 (<0.02 kg).
- 10 higher-consumption gas certs carry PE +0.5..+1.5 kWh/m² AND
CO2 -0.5..-1.1 kg simultaneously. PE-over + CO2-under on the same
certs is the fingerprint of a small gas→electricity fuel-split
difference (elec PE 1.51 > gas 1.13, but elec CO2 0.136 < gas 0.21),
not a factor-value error — next slice candidate.
An earlier "41/47 PE gaps" reading was a JSON-integer-TFA division artifact;
comparing on the worksheet's decimal TFA (which the calculator also uses)
collapses it to the real 10. Worksheet values frozen as literals (the dr87
PDFs are untracked, so not parsed at test time) per the worksheet_unrounded_sap
convention. Also replaced a pre-existing pytest.approx with abs-diff to keep
the file at zero pyright errors (feedback_abs_diff_over_pytest_approx).
106 passed (was 59); pyright 0 errors.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CH6's P960 worksheet input lodges Distribution Loss = "Two adjoining
dwellings sharing a single heating system" → (306) DLF = 1.0000, vs CH4's
"Calculated" → 1.5 → (306) = 1.4500. That DLF choice swings SAP/cost/CO2/PE
materially, but it is NOT present in the Summary PDF that the corpus pipeline
consumes (Summary → ElmhurstSiteNotesExtractor → mapper → calculator).
Proven empirically with a user-supplied controlled pair (CH adjoined
dwellings/Summary_001431 (1) vs (2)): the two Summaries are byte-identical
across every RdSAP INPUT field, differing only in the derived header
(SAP 80 vs 75, bill £954 vs £1237, emissions 5.407 vs 7.394 t). A
case-insensitive scan of the CH6 Summary for "distribution"/"adjoin" returns
0 hits. Since CH4/CH6 Summaries are themselves identical bar fuel type, no
Summary-derivable rule can yield CH4=1.45 AND CH6=1.0.
Doc-only change (comment in _EXPECTATIONS); 20/20 community-heating corpus
tests pass. Closes the CH6 re-litigation: pin held.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 worksheet block 12b/13b (367)/(467) for a community heating
electric heat pump (Table 4a code 304 → Table 12 fuel 41 "heat from
electric heat pump"). The HP meters grid electricity, so per Table 12
note (s)/(t) + block 12b/13b footnote (a) its emission/PE factor is the
MONTHLY Table 12d/12e cascade (fuel 41 = standard-electricity profile),
weighted by the network heat profile, then × 1/heat-source-eff (1/COP):
(367)/(467) = [(307)+(310)] / COP × Σ((307+310)_m × factor_m)/Σ(...)
Per-line walk of CH3 (the displayed (367) 0.1535 / (467) 1.5717 are PDF
artifacts; the (373)/(473) totals reconcile only with):
CO2 factor = 0.15040 (monthly Table 12d wtd) vs cascade annual 0.136
PE factor = 1.55692 (monthly Table 12e wtd) vs cascade annual 1.501
Pre-slice the cascade routed code 304 through the non-electric branch
(`_co2_factor_kg_per_kwh(main) × 1/COP` = annual × scaling). New
`_is_heat_network_electric_main` (heat-network main whose fuel has a
Table 12d monthly set — i.e. fuel 41) routes all four factor helpers
(main + HW, CO2 + PE) through the monthly cascade × 1/COP. Non-electric
heat networks (gas 51 / oil 53 / coal 54) have no monthly set → annual
path unchanged (CH1, CH6 untouched).
Closure (CH3 was already SAP+cost EXACT):
CH3 (HP/Elec) CO2 −75.32→+0.0000 (= [(307+310)/3]×(0.1504−0.136)),
PE −249.32→−0.0000 (× (1.5569−1.501)) — FULLY EXACT
Corpus now 40/41 EXACT on all four metrics. Only CH6 remains: its
worksheet lodges a manual DLF=1.0 ("two adjoining dwellings") absent
from the Summary PDF (byte-identical to CH4 bar fuel type) — an
architectural limit, not a cascade gap. 2226 pass + 1 skip + 0 fail
(tolerances 1e-4 all metrics); pyright net-zero 43→43.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
