Ports the §6.1 conservatory split (declare the four glazed fields; exclude the
glazed BP from the fabric loop; carry it as sap_conservatory) to the remaining
gov mappers that lacked it. Fixes the modelling_e2e construction_age_band
NOT-NULL failures: 5 type-4 conservatory certs on RdSAP-Schema-20.0.0 (e.g.
property 725213) mapped the conservatory to a null-age fabric part that crashed
on persist. 17.0/17.1/18.0 ported preventively (no-op for non-conservatory
certs). 21.0.0 deferred — it never adopted the ADR-0027 all-Optional
SapBuildingPart, so a sparse conservatory part needs that broader change first.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A full-SAP cert (assessment_type=SAP, the as-designed LIG-* new-builds) lodged
under a SAP-Schema-16.x version failed to map with:
ValueError: RdSapSchema17_1: missing required field 'door_count'
— crashing the property's modelling_e2e subtask. 89 distinct properties in the
2026-06-24 run hit this; ~22 of every 30 sampled are this full-SAP shape.
Root cause: from_api_response dispatches on the schema_type STRING only, and the
SAP-Schema-16.x branch assumed a single shape — "reduced-field (RdSAP-shaped)" —
sending every 16.x cert through _normalize_sap_schema_16_x -> RdSapSchema17_1.
But the SAP-Schema-16.x name covers two structurally different certs:
* reduced RdSAP (assessment_type=RdSAP): top-level door_count / glazed_area
band / construction-code building parts.
* full SAP (assessment_type=SAP): measured shape — sap_opening_types +
structured sap_building_parts carrying measured U-values and door/window
OPENINGS, with NO top-level door_count (the door is an opening). These omit
the reduced-only count fields, so the reduced normaliser failed loud on the
first one it checks (door_count) — and 14 others behind it.
Force-fitting a full-SAP cert to the reduced RdSAP schema was the bug: the data
was never missing, it was being validated against the wrong schema.
Fix: discriminate on shape (_is_full_sap_cert: assessment_type=SAP AND
sap_opening_types present) and route full-SAP 16.x certs to the existing
full-SAP 17.1 mapper, which reads the real measured openings (the lodged
0.9x2.1m door -> door_count 1) — no reduced-field defaulting. The only field the
16.x full-SAP shape omits that SapSchema17_1 needs is `tenure` (register
metadata, no SAP effect), defaulted. Reduced 16.x certs (assessment_type=RdSAP,
no opening types) are untouched — all pinned reduced 16.x fixtures stay on the
RdSAP path.
Regression test pins a real full-SAP-16.0 cert (0293-...-8795, lodged 83) mapping
via the full-SAP path + the reduced 16.2 cert staying on the RdSAP path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Mirror the merged 21.0.1 fix (d501535c): declare the four glazed conservatory
fields on the 19.0 SapBuildingPart so from_dict stops dropping them, exclude the
glazed BP from the fabric loop, and carry it as EpcPropertyData.sap_conservatory
(§6.1). Fixes cert 718138 (conservatory_type=4) mis-scoring as a fabric part and
failing to persist on the NOT-NULL construction_age_band.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A SAP-Schema-17.0 full-SAP cohort cert (8265-7433-3220-9736-7902) omits the
top-level `has_hot_water_cylinder` and lodges it only under `sap_heating`. The
required top-level field on SapSchema17_1 made `from_dict` raise and skip the
cert.
Fix: make the top-level field Optional, and have the full-SAP mapper
(`from_sap_schema_17_1`, also used by 17.0/18.0.0 via delegation) fall back to
`sap_heating.has_hot_water_cylinder`. RdSAP mappers are unchanged (they keep the
top-level required field; their SapHeating has no such attribute).
Cert now maps + calculates (sap 76). Regression tests for the nested true/false
fallback.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Review follow-up (Khalim): the first pass made far more optional than needed —
notably the whole SapBuildingPart block — and a buggy 21.0.0↔21.0.1 diff also
MISSED open_chimneys_count / cfl_/led_fixed_lighting_bulbs_count / suggested_
improvements, so the original change actually mapped only 3 of the 33 skipped
certs (the rest still failed on open_chimneys_count).
Re-derived the exact set empirically from all 33 skipped cohort certs:
widen only fields that are (a) required in 21.0.0, (b) already optional in
21.0.1, AND (c) genuinely omitted by ≥1 of those certs. Result:
- KEEP optional: the 4 SapWindow refinements, the top-level vent/lighting/
door/pressure-test block (incl. the 3 previously-missed fields), 2
SapEnergySource fields, Addendum.addendum_numbers, PhotovoltaicSupply.
none_or_no_details, and exactly ONE building-part field
(SapBuildingPart.roof_insulation_thickness — omitted by 7 certs).
- REVERT to required: the other 12 SapBuildingPart fields (construction_age_
band, wall_construction, …), MainHeatingDetail.emitter_temperature,
PvBatteries.pv_battery, ShowerOutlets.shower_outlet — none of the 33 certs
omit these, so they stay strict.
Mapper: coalesce the count fields (wet_rooms_count, open_chimneys_count,
cfl_/led_fixed_lighting_bulbs_count) to 0 like every other mapper, so the now-
optional values can't reach a NOT-NULL column (also drops 4 pyright ignores).
Now maps 32/33 (up from 3); the last cert hits a pre-existing pv_batteries-
shape AttributeError and degrades via the ADR-0031 skip path. pyright net
unchanged (43, no new errors); regression test rewritten to the real omitted set.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The modelling_e2e cohort skipped ~35 real RdSAP-Schema-21.0.0 certs with
"SapWindow: missing required field 'frame_factor'" (and a cascade of
wet_rooms_count, the mechanical-vent duct block, wind_turbine_details, &c.).
These are complete certs — the `RdSapSchema21_0_0` dataclass was simply
modelled stricter than `RdSapSchema21_0_1`, which already treats every one of
these fields as optional. This aligns 21.0.0's optionality with 21.0.1 (the
proven path) so the certs map into the prediction donor pool instead of being
dropped:
- SapWindow: pvc_frame / glazing_gap / frame_factor / window_transmission_details
→ Optional (calc already falls back: Table 6c frame factor, SAP10 glazing
lookup, type-only U).
- 20 nested fields across Addendum / MainHeatingDetail / PhotovoltaicSupply /
PvBatteries / SapBuildingPart / SapEnergySource → Optional, mirroring 21.0.1
verbatim (classes made kw_only so defaults sit in place; parsed only via
from_dict, keyword construction).
- from_rdsap_schema_21_0_0: guard the window_transmission_details dereference
for None (mirrors the 21.0.1 `_api_sap_window` guard).
Existing 21.0.0 certs are unaffected (relaxing optionality does not change
parsing of certs that carry the fields); mapper-corpus + accuracy gates green.
Verified end-to-end against real cohort cert 2205-3036-3484-0400-5718:
maps + calculates (SAP 68). Regression test added.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The gov API lodges a NON-SEPARATED conservatory (conservatory_type=4) as a
glazed "building part" carrying only {floor_area, room_height,
double_glazed, glazed_perimeter} — no fabric, no floor dimensions. The
four fields were undeclared on the 21.0.1 SapBuildingPart, so `from_dict`
dropped them and the conservatory was silently lost: it billed no §6.1
window/rooflight/floor and added nothing to TFA (5 corpus certs over-rated
— too little heat loss → SAP too high).
Fix (21.0.1 schema + mapper):
- declare the four glazed fields on `SapBuildingPart`;
- `_api_sap_conservatory` builds `EpcPropertyData.sap_conservatory` from
the glazed BP (identified by a lodged `glazed_perimeter`; only type-4
conservatories lodge it — separated ones, §6.2, lodge nothing);
- exclude the glazed BP from the fabric building-part loop (it is billed
by the §6.1 cascade, not as a dwelling part);
- `_total_floor_area_from_building_parts` adds the conservatory floor area
to TFA (drives occupancy → §4/§5 demand).
Validation is cross-mapper parity, NOT a corpus back-solve: the API mapper
feeds the SAME worksheet-validated §6.1 cascade (`conservatory_geometry`,
pinned to 1e-4 against the case-44 Summary) as the Elmhurst path — so the
API conservatory fabric is correct by construction. `from_api_response`
on an injected type-4 cert reproduces the glazed wall (perimeter × ground-
floor room height = 22.05), glazed roof (floor/cos20 = 12.77) and Table 25
double U_eff (2.758 wall / 2.993 roof); a separated (type 2/3) cert lodges
no glazed BP → disregarded per §6.2.
Gauges: corpus within-0.5 67.9% → 68.6% (MAE 0.959 → 0.942; floor 0.67→0.68,
ceiling 0.97→0.95); /tmp eval mean|err| 0.822 → 0.817. Harness 47/47
0-raised; regression = the 3 pre-existing fails; pyright net-zero (65=65).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Some SAP-Schema-17.x/18.0.0 certs lodge sap_openings width/height in MILLIMETRES
mixed with metre rows in the same array (e.g. a 2025x2100 mm window beside a
3.06x1 m one). The 17.1 mapper read them all as metres → a 4.25M m2 window →
HTC in the millions → SAP clamped to 1.
Fix (TDD, datatypes/epc/domain/mapper.py): _sanitise_opening_dimension_m treats
any dimension > 50 m as mm and divides by 1000; _sap_opening_area_m2 applies it
to areas. Wired into the window, roof-window, and door-area-weighting paths.
The 3 broken certs (uprn_10093117227 / 10090317693 / 10091636031) now score
90 / 81 / 79 instead of 1.
3 RED->GREEN slices + refactor; new test class
TestFromSapSchema17_1OpeningUnitSanitisation + sap_17_1_mm_openings.json fixture;
0 new pyright errors; no regressions.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Schema coverage (datatypes/epc/domain/mapper.py):
- SAP-Schema-18.0.0: full-SAP shape ≡ 17.1 → from_sap_schema_17_1, no normalisation.
- SAP-Schema-16.0: same reduced-field 16.x path; default the omitted `tenure`
field in _normalize_sap_schema_16_x (metadata; SAP cascade never reads it).
Genuinely sparse 16.x certs (missing core fabric fields) still fail loud.
- Regression tests + sap_18_0_0.json / sap_16_0.json fixtures; 0 new pyright errors.
Autonomous triage of the worklist (scripts/hyde/autonomous_run_findings.md):
- Found + diagnosed 2 bugs (flagged, NOT fixed): (1) MAPPER — full-SAP openings
lodged in mm read as m → multi-million-m2 windows → SAP clamps to 1 (uprn_
10093117227 / 10090317693 / 10091636031); (2) CALCULATOR — database heat-pump
fuel code 39 mis-priced as gas, over-rates ~14 (uprn_10093114053).
- Most certs map within +/-4 of lodged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- SAP-Schema-16.3: same reduced-field RdSAP shape as 16.2 — generalise the
normaliser to _normalize_sap_schema_16_x and route both 16.2/16.3 through it.
uprn_44012843 maps → SAP 79 (lodged 81).
- SAP-Schema-17.0: structurally identical to the full-SAP 17.1 schema (measured
sap_opening_types), so it parses with the 17.1 dataclass and reuses
from_sap_schema_17_1 with no normalisation. uprn_10023444324 → 80, uprn_
10023444320 → 81.
- Regression tests (16.3 dispatch, 17.0 dispatch) + sap_16_3.json / sap_17_0.json
fixtures; 0 new pyright errors. All 7 e2e UPRNs now map.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP-Schema-16.2 (datatypes/epc/domain/mapper.py):
- 16.2 is structurally an RdSAP-17.1 cert under a different name; add
_normalize_sap_schema_16_2 (field renames + defaults) and dispatch to the
tested from_rdsap_schema_17_1 mapper. uprn_100020933699 maps → SAP 71.
- Honour a "Single glazed" windows description when multiple_glazing_type="ND"
(was defaulting to double) → RdSAP-21 code 5; eng 72→71 (lodged 70).
- 4 regression tests + sap_16_2.json fixture; 0 new pyright errors.
Flat party-wall fix (domain/sap10_calculator/worksheet/heat_transmission.py):
- Full-SAP flats carry flatness in dwelling_type, not property_type, so the
party-wall default fell through to the 0.25 house value instead of the RdSAP
Table-15 flat 0.0. Add _is_flat_or_maisonette_dwelling fallback + regression
test. uprn_10093116529 80→81 (matches the cert's lodged party u_value 0).
Accuracy corpus pins (tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py):
- uprn_10093116543 (SAP-17.1 gas-combi semi): engine 81 (Elmhurst 77; documented
full-SAP→RdSAP residual — measured wall/floor U + PCDB boiler vs RdSAP defaults).
- uprn_10093116529 (SAP-17.1 g/f flat): engine 81 (Elmhurst 78).
devcontainer: add poppler-utils (pdfinfo) for the documents-parser PDF fixtures.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The gov API lodges a §3.9.2 Simplified Type-2 RR (a room-in-roof bounded by
continuous common walls) under `room_in_roof_type_2` — gable + common-wall
lengths AND heights. The block was undeclared → `from_dict` dropped it →
neither the Type-1 nor Detailed path fired → the cascade's Simplified branch
billed the WHOLE A_RR shell (12.5√(floor/1.5)) at the Table-18-col-4 default
with no gable/common-wall deduction (over-count → under-rate; 7 corpus certs
at signed −5.02).
Fix: declare `RoomInRoofType2` on rdsap_schema_21_0_0/_21_0_1 + SapRoomInRoof,
and build `detailed_surfaces` by MIRRORING the worksheet-validated Summary
path (`_map_elmhurst_rir_surface`, is_simplified) rather than back-solving:
common wall → L × (0.25 + H) (billed at the main-wall U)
gable → L × (0.25 + H) − Σ (H − H_cw)²/2 (RdSAP 10 §3.9.2 + Table 4)
The gable correction sums all common walls (exposed/party/sheltered, incl.
the H=0 absent-gable negative-area case that deducts from the A_RR residual);
a Connected gable sums only the common walls it overtops. The
`gable_wall_type_*` code routes the kind (0/1/2/3 = Party/Exposed/Sheltered/
Connected). A raw-L×H prototype scattered; the §3.9.2 quadratic is the
missing piece.
Validation is cross-mapper parity, NOT a corpus back-solve: `_api_type_2_
surfaces` produces surfaces IDENTICAL to the Summary path on cohort cert
000565 (connected_wall 3.68, gable_wall_external 16.08/27.68, common walls,
and the −0.17 absent-gable quadratic), and 000565 is pinned to 1e-4 in the
harness — so the API RR fabric is now correct by construction. The remaining
type-2 cohort SAP scatter is unrelated per-cert causes (stone walls,
secondary fuel), not the RR.
Gauges: corpus within-0.5 67.6% → 67.9% (MAE 0.979 → 0.959); /tmp 71.7% →
71.8% (MAE 0.838 → 0.822). Harness 47/47 (000565 unchanged); regression =
the 3 pre-existing fails; pyright net-zero (65=65).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Follow-on to the slope/stud slice. A Detailed RR (RdSAP 10 §3.9.2) can also
lodge `common_wall_*` — the wall separating the room-in-roof from the rest of
the cold roof void. Those fields were undeclared → `from_dict` dropped them →
`_api_rir_detailed_surfaces` omitted the common walls → the RR undercounted
wall heat loss → over-rate.
Fix: declare `common_wall_length/height_1/2` on `RoomInRoofDetails`
(21_0_0 + 21_0_1) and build `kind="common_wall"` surfaces (raw L × H area to
2 d.p.). The cascade's Detailed-RR branch already bills common walls at the
storey-below main-wall U (Table 4 p.22 "Common wall") and deducts their area
from the §3.10.1 residual roof — no calculator change. No insulation thickness
is read: common walls take the main-wall U, not a Table 17 RR-element U.
6 /tmp certs carry detailed `common_wall_length_1`: cohort mean|err| 2.43 ->
1.25 (all were over-rating; e.g. 2877-3059 +4.55 -> +2.79). Gauges: corpus
within-0.5 67.5% -> 67.6% (MAE 0.987 -> 0.979); /tmp 71.6% -> 71.7%
(MAE 0.846 -> 0.838). Harness 47/47 0 raised; regression = the 3 pre-existing
fails; pyright net-zero (65=65).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The gov-EPC API lodges a Detailed RR (RdSAP 10 §3.9, Figure 4) with up to
two sloping ceilings (`slope_*`) and two vertical stud/knee walls
(`stud_wall_*`) in addition to the gable + flat-ceiling surfaces. Those
slope/stud fields were undeclared on the 21.0.x schema, so `from_dict`
silently dropped them and `_api_rir_detailed_surfaces` built ONLY the gable
+ flat-ceiling surfaces. The (large) sloping roof and the knee walls
contributed ZERO heat loss → undercounted RR fabric loss → a systematic
over-rate.
Fix: declare `slope_*`/`stud_wall_*` on `RoomInRoofDetails`
(rdsap_schema_21_0_0 + _21_0_1) and build `kind="slope"` / `kind="stud_wall"`
surfaces in the mapper. The cascade's Detailed-RR branch already routes both
to the roof aggregate via `u_rr_slope` (Table 17 col 1) and `u_rr_stud_wall`
(Table 17 col 3) — RdSAP 10 §5.11.3, p.43-44 — so no calculator change is
needed (Summary path worksheet-validated by the 000565 detailed-RR fixtures).
insulation_type is left None to defer to the Table 17 col-(a) mineral-wool
default, mirroring the existing flat_ceiling branch.
15 /tmp certs carry `slope_height_1`: cohort mean|err| 4.26 -> 2.05, signed
+4.09 -> centred (14/15 were over-rating; e.g. 0390-2538 +5.95 -> +3.56).
Gauges: corpus within-0.5 67.3% -> 67.5% (MAE 1.020 -> 0.987); /tmp 71.4% ->
71.6% (MAE 0.882 -> 0.846). Harness 47/47 0 raised; regression = the 3
pre-existing fails; pyright net-zero (65=65).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The gov API lodges a manufacturer's declared cylinder loss factor
(kWh/day) in `sap_heating.cylinder_heat_loss`, in which case it leaves
the cylinder volume / insulation type / thickness None. That field was
undeclared on the 21.0.x schemas, so `from_dict` dropped it — then
`_cylinder_storage_loss_override` hit its insulation-None / volume-None
guards and returned None, dropping the §4 storage loss ENTIRELY. The
dwelling over-rated (the declared loss is typically ~1.5 kWh/day ≈
550 kWh/yr).
SAP 10.2 §4 branch a) (PDF p.136): when the declared loss factor is
known, storage loss (50) = (48) declared loss × (49) Table-2b
temperature factor — replacing the Table 2 V×L×VF computation.
- declare `cylinder_heat_loss` on RdSapSchema21_0_0/21_0_1.SapHeating +
EpcPropertyData.SapHeating; thread through the 21.0.x mappers.
- `cylinder_storage_loss_monthly_kwh` gains `declared_loss_kwh_per_day`:
when set, combined_55 = declared × TF (volume/insulation unused).
- `_cylinder_storage_loss_override` resolves the declared loss BEFORE the
insulation/volume guards (the gov omits those when the loss is lodged).
12 /tmp certs carry it (mean |err| 3.00 -> 2.51; the clean ones close
hard, e.g. 2360 2.65 -> 0.30, 0245 2.25 -> 0.53). Corpus within-0.5
67.0% -> 67.3% (MAE 1.025 -> 1.020); /tmp 71.2% -> 71.4% (0.889 ->
0.882). Worksheet harness 47/47; regression = only the 3 pre-existing
fails; pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Roofs lodged insulated at rafters carry their thickness in a DEDICATED
gov-EPC API field, `rafter_insulation_thickness` (e.g. "225mm"), while
`roof_insulation_thickness` stays None (rafters aren't loft joists). That
field was undeclared on the 21.0.x schemas, so `from_dict` silently
dropped it — the rafter certs only *looked* redacted (roof EER 2-4 =
insulated, yet no thickness), and the cascade fell to the Table 18 col (2)
unknown default (2.30), badly under-rating them.
- declare `rafter_insulation_thickness` on RdSapSchema21_0_0/21_0_1 +
EpcPropertyData.SapBuildingPart (mirrors the existing
sloping_ceiling_/flat_roof_insulation_thickness dropped-field handling).
- thread it through `from_rdsap_schema_21_0_0/21_0_1` (older schemas get
None via getattr).
- `heat_transmission` prefers `rafter_insulation_thickness` over
`roof_insulation_thickness` when the part is at-rafters, so the measured
RdSAP 10 §5.11.2 Table 16 column (2) row applies (225 mm → 0.25).
Completes the rafters roof fix: with the real thickness read, the rafter
certs are recovered rather than over-stated — cert 3100-8675-0922-8628
(band E, rafters 225mm) +8.93 → +0.43 SAP. Corpus within-0.5 67.0%
(MAE 1.025) and /tmp 71.2% (MAE 0.889) — both NET ABOVE the pre-rafters
baseline (66.9% / 70.6%). Worksheet harness 47/47; regression = only the
3 pre-existing fails; pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_synthesise_20_0_0_sap_windows` passed `schema.multiple_glazing_type`
straight into `_api_cascade_glazing_type`, which raised UnmappedApiCode on
the "ND" (Not Defined) string that the 20.0.0 corpus lodges alongside the
1-8 integer codes — failing the mapper-coverage guard on every ND-glazed
20.0.0 cert. Mirror the existing 18.0/19.0/17.x seams: route integer codes
through the cascade, fall the "ND" string back to the DG-modal default
(cascade code 2 → daylight g_L 0.80). Also corrects the 20.0.0 schema
field type `int` → `Union[int, str]` to match the data (as 18.0 already
does), which keeps the isinstance guard pyright-clean.
Pre-existing failure (present before this branch's recent commits), not in
the handover regression gate. Fixes all 15 RdSAP-Schema-20.0.0 ND certs;
test_mapper_corpus 6002/6002 pass. pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Dispatch RdSAP-Schema-17.0 through from_api_response, parse-fix the schema
(data-driven required->optional, validated against the 1000-cert 17.0 corpus
per ADR-0028 — incl. SapHeating.cylinder_insulation_type and the
has_hot_water_cylinder / has_fixed_air_conditioning / has_heated_separate_
conservatory flags), and port the defensive mapper reads (dwelling_type
str/dict/number, photovoltaic_supply guard, sap_floor_dimensions guard). All
1000 corpus certs now parse and map.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Dispatch RdSAP-Schema-19.0 through from_api_response, parse-fix the schema
(data-driven required->optional, validated against the 1000-cert 19.0 corpus
per ADR-0028), and port 18.0's defensive mapper reads (dwelling_type str/dict/
number, photovoltaic_supply guard, sap_room_in_roof Measurement coercion).
All 1000 corpus certs now parse and map.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The gov-EPC API surfaces the assessor's RdSAP-assessed per-element U-values
as `roof_u_value` / `wall_u_value` / `floor_u_value` on each building part.
These were undeclared on the RdSAP 21.0.0/21.0.1 schemas, so `from_dict`
silently dropped them, and `heat_transmission` re-derived each U from the §5.6
/§5.7/§5.11 construction-default cascade. The gov OPEN data routinely redacts
the backing insulation thickness, so that re-derivation mis-bills an insulated
element as uninsulated.
RdSAP 10 §5.1: a known element U-value (documentary evidence / the lodged
RdSAP output) is used directly in place of the construction-default cascade.
Per [[project_per_cert_mapper_validation_state]] the gov API carries RdSAP
OUTPUT, so the lodged U reproduces the official's element heat loss exactly.
Worst case in the 2026 sample: cert 7921-0052-0940-5007-0663, an age-C
"Pitched, sloping ceiling" (rc=8) top-floor flat lodging roof_u_value=0.2 with
no thickness. The cascade returned the uninsulated 2.30 W/m²K → SAP 56.9 vs
lodged 80 (-23.09, the single largest error in the sample). The roof override
alone recovers ~15 SAP; the wall override (lodged 0.34 vs cascade) closes the
rest of this cohort.
Override applies to the MAIN wall only (alt-wall sub-areas keep their own
per-area U) and the part's floor=0. Fires only when the rare field is present
(9 of 909 computed certs), so the Summary path — which never lodges these
API fields — is untouched.
API gauge: 67.1% → 67.7% within-0.5, mean|err| 1.024 → 0.992.
Worksheet harness: 47/47, 0 divergers (unchanged).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_CYLINDER_SIZE_CODE_TO_LITRES` held only codes 2/3/4 (Normal/Medium/Large →
110/160/210 L); codes 5 (Inaccessible) and 6 (Exact) fell through to None,
so the Table-13 high-rate fraction AND the cylinder storage loss were skipped
for those certs (20 code-6 certs in the API sample).
Per RdSAP 10 Specification (10-06-2025) §10.5 Table 28 (PDF p.55):
- Code 6 "Exact": use the lodged measured volume. The gov API carries it in
`cylinder_size_measured` (e.g. 150 L) — now plumbed through the 21.0.0/21.0.1
schema → mapper → `SapHeating.cylinder_volume_measured_l`.
- Code 5 "Inaccessible": 210 L if off-peak electric dual immersion, 160 L from
a solid-fuel boiler, otherwise 110 L (n=0 in the current sample, but
spec-complete).
New `_cylinder_volume_l_from_code` centralises Table 28 resolution and replaces
the three raw-dict call sites (`_hot_water_cylinder_volume_l`, the cylinder
storage-loss path, and the PCDB performance check) so all three honour codes
5/6 identically. `_cylinder_inaccessible_volume_l` applies the code-5 context
rule via the existing immersion/off-peak-meter/solid-fuel-boiler detectors.
Worksheet harness UNAFFECTED (47/47, 0 divergers): the Summary path lodges
neither code 5/6 nor a measured volume. API gauge: within-0.5 64.4% -> 65.1%
(mean|err| 1.085 -> 1.075) — the 20 code-6 certs now size their cylinder from
the measured volume. 4 AAA tests (code 6 measured; code 5 solid-fuel/default/
off-peak-dual-immersion). pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
ADR-0027 Reduced-Field Synthesis: certs with no per-window array now get total
glazing = 0.148 x TFA x band-multiplier (median + quartile multipliers fit from
the 1000 real 21.0.1 certs), split 4-way across N/E/S/W with width=area/4,
height=1.0; glazing_type routed through the verified 21.0.1 cascade. Also guard
optional PhotovoltaicSupply.none_or_no_details (a parse straggler). Corpus maps
983/1000, up from 974.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Required->optional defaults (kw_only + data-driven from corpus presence) so
993/1000 certs that omit sap_windows parse, and honest Union[str, DescriptionV1]
typing for description/dwelling_type which the corpus lodges as localised dicts
in ~half the certs. The never-run 20.0.0 mapper path now produces EpcPropertyData;
974/1000 corpus certs map (xpass), up from 7.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Audit of the API-SAP error (53% within 0.5) localised the systematic
under-rate to ELECTRIC FLATS (houses sit at 60-66% within 0.5; electric
flats 13-19%). Decomposing the flat error showed it tracks space-heating
demand per m² — the worst certs reach 130-289 kWh/m² (accurate certs sit
at 14-110), i.e. a grossly over-stated fabric heat loss, amplified ~4x by
the electricity unit price and the steep low-band SAP log curve.
Root cause: the gov-EPC API lodges `sheltered_wall="Y"` on alternative
wall sub-areas (a sub-area adjacent to an unheated buffer — stair core,
adjoining structure), but the field was dropped by the schema + domain
dataclasses and the calculator billed the alt sub-area at its full
exposed U. RdSAP 10 Table 4 (PDF p.22) "Sheltered": such a wall carries
an added external surface resistance R=0.5 m²K/W → U_sheltered =
1/(1/U + 0.5) — the SAME adjustment the main wall already applies for
`gable_wall_type=2` (`gable_wall_sheltered`,
`_SHELTERED_GABLE_ADDED_RESISTANCE_M2K_W`). Cert 0340-2976 (band-A flat,
42 m² sheltered timber-frame alt) over-stated its wall channel by
~58 W/K → walls 128 -> 70 W/K.
Threads the field end-to-end: schema dataclasses (21.0.0/21.0.1) +
domain `SapAlternativeWall.is_sheltered` (default False — the Summary/
Elmhurst path leaves it False, sheltering rides through its lodged
U-value there, so goldens are untouched) + `from_api_response` mapping
`"Y"->True` + `_alt_wall_w_per_k` applying the 0.5 resistance on the
cascade path (lodged-U and basement alt-walls return before it).
140 certs (15% of the corpus) carry a sheltered alt-wall; they under-
rated at median -0.82 / mean signed -1.33 / 23% within 0.5. Eval: 102
improved, 38 regressed (offsetting-error cases — fix is spec-uniform per
[[feedback_software_no_special_handling]]); within-0.5 53.14% -> 54.24%,
within-1.0 67.99% -> 69.64%, within-2.0 81.85% -> 83.50%, mean|err|
1.312 -> 1.248, 909 computed / 0 raises. Goldens (6035, 000565) and full
calc/epc/parser regression green; pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A "Pitched, sloping ceiling" (roof_construction == 8) lodges its
insulation in the dedicated `sloping_ceiling_insulation_thickness` field,
not `roof_insulation_thickness` (which stays None — the loft-joist field
is meaningless for a slope-following ceiling). The schema dataclasses
dropped that field, so `from_dict` discarded it and the cascade treated
the slope as uninsulated; worse, the pre-1950 None-fallback forced 0 mm
(U=2.30), over-stating roof heat loss ~74%.
Surface the field on SapBuildingPart (schemas 21.0.0 / 21.0.1) and prefer
it in `_api_resolve_sloping_ceiling_thickness` when it carries a NUMERIC
thickness: "100mm" now reaches Table 17 column (1a) "Insulated slope –
sloping ceiling, mineral wool/EPS" (RdSAP 10 §5.11.3 p.44 — 100 mm →
U=0.40) instead of 2.30. Categorical lodgements ("AB" As Built / "NI")
are not measured thicknesses, so they fall through to the existing
as-built rule (Table 18 col (3) via is_pitched_sloping_ceiling).
Cert 9884-3059-9202-7506 (code 8, age B, sloping 100 mm): SAP −5.54 → +0.06.
Cert 8036-2925-6600-0202: −4.94 → +1.55. No regressions in the roof-8
cohort (the "AB" certs are unchanged). Eval headline 43.8% → 44.3% within
0.5; golden fixtures incl. 6035 green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
