100-cert probe, seed=7, sap_score window 5..99. MAE 4.29
(vs 8.41 on 2026-05-18 with the older 20..95 window — the
delta blends calculator improvements with sample-window
change, so this is logged as the post-P5 reference, not as
"P5 reduced MAE".)
P5 itself was pure trace exposure; the calculator's SAP
output should be numerically unchanged. The headline finding
from this run is primary-energy over-prediction: PE MAE
44.40 kWh/m², bias +39.66 — now the dominant signal with
SAP residuals halved. Each end-use PE contribution surfaces
on SapResult.intermediate per P5.12, so the next session
can localise the bias without re-instrumenting.
Closes the second half of P5 (HANDOVER_SYSTEMATIC_REVIEW §2.5):
- Adds test_bre_worked_examples.py — one comprehensive test that
locks every published SapResult.intermediate key against its
SAP 10.2 worksheet item number ((4) TFA, (33) fabric heat loss,
(39) HTC, (40) HLP, (73) gains, (93) mean internal temp, (98c)
space heating, (240e/247/250) costs, (252) PV credit, (256)
deflator, (257) ECF, (261-272) per-end-use CO2, (275-287)
primary energy per m²). All formulas derived independently from
the worksheet pages 131-148; passes against the synthetic
100 m² baseline.
- Explicit caveat in module docstring: BRE-published worked
examples don't exist in any of the three SAP-spec PDFs we have
(rdSAP10, SAP10.2, SAP10.3 — all greppped). The test is
spec-formula-derived, not BRE-validated. Structure stays if
BRE numbers surface later; only expected values change.
Also surfaces and documents an RdSAP10 spec drift in
PARITY_FINDINGS.md: Table 32 (page 95 of rdSAP10) gives
Energy Cost Deflator = 0.42, vs the code's 0.36 (SAP10.2 Table 12,
worksheet item (256)). Not changed in P5 — needs ADR-level
resolution on whether the calculator targets SAP10.2 (0.36) or
RdSAP10 (0.42) ratings.
P5 (SapResult.intermediate population + BRE worked-example
fixtures) is now complete on this branch.
Adds ADR-0010 superseding ADR-0009's spec-version target, PCDB
sequencing, and cert-calibration layer. Captures the conclusions
of a grill-with-docs session:
1. Active spec target is SAP 10.2 (14-03-2025), not SAP 10.3 — no
SAP-10.3-lodged certs exist in the corpus to validate against.
2. table_12_cert_calibration is deleted (not "re-derived at the
end"). It was pre-March-2025 spec prices fit against a mixture
distribution of two spec-version regimes, with downstream-
component bugs absorbed into the fit — not Elmhurst deviation.
3. Validation Cohort: filter the corpus to inspection_date ≥
2025-07-01 so every cert in the probe was lodged on SAP 10.2
(14-03-2025) prices. One spec, one signal.
4. PCDB integration is promoted from "Session C deferred" to
prerequisite P4 — dominates residual variance on heat pumps and
the 78% of gas-boiler certs lodging main_heating_data_source=1.
5. Trace mode (SapResult.intermediate) and BRE worked-example
fixtures replace the 7 cert-based golden fixtures, which
contained compensating errors.
6. Strict-type EpcPropertyData via codes.csv-derived canonical
enums (P6) — the in-source motivation lives at
dimensions.py:74-82 (Khalim's comment, included in this commit).
7. Worksheet-faithful structure is a sweep-time principle: each
worksheet module mirrors SAP 10.2 worksheet line numbering.
CONTEXT.md additions:
- Refined "Calculated SAP10 Performance" and "SAP10 Calculation"
to reference SAP 10.2 + ADR-0010.
- New term "SAP Spec Version" — domain-meaningful because the
same EpcPropertyData yields different sap_score under different
spec revisions.
- New term "Validation Cohort" — the version-locked sub-corpus.
HANDOVER_SYSTEMATIC_REVIEW.md is rewritten section-by-section to
reflect ADR-0010: §1 framing, §2 status pointer, new §2.5 with the
six prerequisites P1–P6 in dependency order, §3 diagnosis (cert-cal
was stale prices, not Elmhurst deviation), §4 scope (PCDB IN,
SAP 10.3 stays OUT), §5 approach (worksheet-faithful principle as
§5.5), §7 tension dissolved, §7b findings re-framed, §8 dead-ends
re-classified as conditional, §9 cohort filter, §10 fixture
strategy, §11 trace mode as prerequisite, §12 prereqs-first,
§13 Phase 0/Phase 1 workflow, §14 ADR-0010 reference, §15 final
note.
P2.1 (commit ac1aa56a) already lands the first ADR-0010 slice
(probe swap to spec prices).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
§7b "Outstanding findings to pick up during the systematic pass"
collects spec-correct fixes that were reverted because they regressed
SAP MAE against the corpus — but the spec basis is unambiguous and
they WILL be the right answer once cert-calibration is re-derived.
Treat as TODOs, not dead-ends. Documents:
Finding 1 — HW cylinder zero-loss for combi (PE MAE -6.64 measured)
Finding 2 — Standing charges Table 12 note (a)
Finding 3 — Cat=10 room-heater Table 12a fractional blending
Finding 4 — Lighting Appendix L proper (L1-L12 cascade)
Finding 5 — Internal-gains Table 5 water-heating + losses rows
Finding 6 — Storage-loss-factor table values 3× off spec
Finding 7 — Heat-pump fallback (needs PCDB)
Finding 8 — Smaller gaps carried forward
Each documents the spec section/page reference, the current code
bug, empirical impact where measured, and when to pick up during the
section-by-section sweep.
PCDB section strengthened from "deferred to Session C" to an explicit
roadmap: data source URL, lookup key (main_heating_index_number),
fields needed, recommended sequencing (after spec sweep so cert-cal
is re-derivable), and why-not-now (cert-cal currently masks PCDB gaps).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
The slice-by-slice "fix the biggest residual" approach has hit a
ceiling at SAP MAE ~4.6 because the cert-calibration prices absorb
multiple structural deviations from spec. Any spec-correct fix in one
component breaks the calibration for others. Three failed slices this
session (standing charges, cat=10 routing, combi zero-loss) made the
pattern unambiguous.
Pivot: systematic section-by-section spec verification. Read the
RdSAP 10 + SAP 10.2 spec in order, check each table / formula /
footnote against the corresponding code, fix gaps one at a time.
Build the spec-correct engine first; re-derive cert-cal calibration
once at the end as a thin Elmhurst-compatibility layer.
Handover doc covers:
- Critical framing (deterministic, not assessor judgement)
- Current state (SAP MAE 4.61, PE MAE 43.32 at f4a8d2a0)
- Why the slice-by-slice approach won't converge
- Scope decisions (RdSAP 10 + SAP 10.2 only; park full-SAP + PCDB)
- Section-to-code mapping
- Known dead-ends to skip
- Cert-calibration vs spec-correctness tension and how to resolve it
- The 7 golden fixtures and their compensating-error caveats
- Trace mode recommendation (ADR-0009's `intermediate` field)
- Specific §1-3 starting tasks
- Workflow recap
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Per user suggestion: the iteration history in this chat has likely
accreted blind spots that a long context window can't shed (e.g. I
spent slices comparing our delivered kWh to the cert's primary kWh
without noticing the apples-to-oranges error). A fresh agent reading
the SAP 10.2 + RdSAP 10 PDFs cold against the current calculator may
spot gaps faster.
HANDOVER_FRESH_REVIEW.md gives the fresh agent:
- Current state (MAE 5.34, primary-energy bias +51 kWh/m²)
- Repo layout pointer
- Priority-ordered dig list (PEUI mystery first)
- Validated truths
- Dead-end list (don't repeat S-B5 NI thickness switch etc.)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Per user suggestion (switch from probe-driven to worksheet-driven
iteration), enumerates the §§1-15 worksheet + Appendices A-U state in
the calculator with a status grade and a prioritised gap list. Becomes
the roadmap for Session B remaining slices.
Next slice from this list: Table 11 secondary heating allocation —
10% fraction on most boiler-main certs that we currently model as 0.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Verified against the SAP 10.2 spec (14-03-2025): Table 12 unit prices
are IDENTICAL to SAP 10.3 Table 12. Both specs mandate (§12.2): "Fuel
costs are calculated using the fuel prices given in Table 12. Other
prices must not be used for calculation of SAP ratings." The legacy
ML-pipeline prices in domain.ml.sap_efficiencies (3.48 gas, 13.19 elec,
5.50 E7-low) do NOT match either SAP 10.2 or 10.3 and appear to be a
pre-2022 holdover.
New module domain.sap.tables.table_12 carries the spec-correct
values:
mains gas: 3.64 (was 3.48 legacy)
standard electricity: 16.49 (was 13.19)
7h-low / Economy-7: 9.40 (was 5.50)
24h-heating: 14.04 (was 6.61)
Also corrects an S-B4 bug: SAP 10.2 Table 12a shows direct-acting
electric heating (codes 191-196) runs at 90% high-rate on 7h tariffs,
not 0% — only true storage heaters (401-409, 421-425) bill at the
low rate. _E7_SPACE_HEATING_CODES narrowed accordingly.
100-cert parity probe with spec-correct prices:
MAE 4.66 → 6.66 (regression vs legacy prices)
bias -0.70 → -4.66 (over-counting cost)
spec-correctness: SAP 10.2 verbatim
The MAE regression confirms the corpus's lodged ratings were NOT
calculated against the published SAP 10.2 Table 12 prices. The cert
ratings appear to use the legacy lower prices despite reporting
sap_version=10.2. Three paths forward documented in next commit's
discussion thread.
Also adds the SAP 10.2 spec PDF to docs/sap-spec/.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds services/ml_training_data/src/ml_training_data/sap_parity_probe.py
— samples N certs from the v18a corpus, streams them via BulkZipReader,
runs Sap10Calculator, prints MAE/RMSE/bias + worst-N residuals. Baseline
across 100 certs: MAE 8.41, RMSE 13.98, bias -2.65, 0 errors.
docs/sap-spec/PARITY_FINDINGS.md captures the dominant failure pattern
(flats + bungalows under-predicted, 10 of the worst-15 are flats whose
floor/roof are party with neighbouring dwellings) and the priority-
ordered Session B iteration backlog (S-B-flat-surfaces first).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Promotes ADR-0009 from Proposed to Accepted after the grill-with-docs
session resolved all seven open questions. Bundles the SAP 10.3 and
RdSAP 10 specifications under docs/sap-spec/ plus a calculator design
sketch (module layout, monthly-loop pseudo-code, status table).
CONTEXT.md adds three new domain terms parallel to existing performance
language:
- Calculated SAP10 Performance (parallel to Effective / Lodged)
- SAP10 Calculation (process; implemented by Sap10Calculator)
- Measure Application (process; implemented by MeasureApplicator)
ML pipeline is NOT retired — it stays as the residual head once the
calculator reaches parity in Session B. ADR-0009 §"Grill outcomes" carries
the seven binding scope decisions plus three Session-A-scope changes
discovered during the grill (RdSAP §19 EER formula, SAP 10.2 Appendix A
cross-reference, RdSAP Table 29 cascade defaults).
