Second sanctioned exception to "ratchets never loosen" — needs @KhalimCK's
call, since the prior note expected to re-tighten here. Exactly one cohort
property is WHC 950 (16 Bingley Close, +5.946 -> +6.818 = the whole +0.0043);
within-0.5 unchanged at 23.9%. Its pre_sap is verified correct but its ~+6
residual is a known extraction bug, and this hybrid gauge cannot adjudicate a
calculator fix (#1592 Problem 2). The gov-API corpus, which gauges the
calculator alone, improves.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Enumerates the 3 corpus certs that can move (all WHC 950) individually per
#1592 sub-task D: two improve (one crossing inside 0.5), one worsens and is
handed to sub-task C for an accredited oracle. No loosening required.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
pytest.approx is untyped under pyright strict, so the new assertions added
3 errors against the repo's zero-new-errors bar. Switches to the abs(...)
<= tol form already dominant in this file. No behaviour change.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 Table 3 ("For heat networks apply the formula above with p = 1.0
and h = 3 for all months") and §4.3's "insulated pipework" literal both
scope on the DHW source, so a water-only network gets the same row as a
network space main. Was falling back to the RdSAP §3 age-band default —
band E → p=0, h=5 — billing 64.58 kWh in January against the spec's 23.26.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 §4.3 (p.24) scopes itself to "where hot water is provided by a
heat network" and requires the Table 3 primary loss, so the gate keys on
the DHW source. Checked off the WHC before the main-keyed branches so a
non-boiler space main (cert 9093's warm air) can't zero it out.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
950 boilers / 951 CHP / 952 community heat pump differ only in plant
efficiency, which SAP 10.2 §4.3 puts in the Table 12 heat price — so the
dwelling's delivered-heat demand must not vary with it. Passes on the
previous commit's expression; verified RED against the prior impl, where
951 leaked 0.80/0.75 and 952 under-billed its DHW fuel by 3.15×.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
SAP 10.2 §4.3 (p.24) puts the water-heating efficiency in the Table 12
heat price, and C4 (p.53) scopes the plant efficiency to CO2/PE only, so
worksheet (310) = (64) × (305a) × (306) carries no efficiency term. The
dwelling-side divisor was applying it a second time.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Read stored lodged EPCs whatever refetch_epc says, so a stored assessment
can win the ADR-0001 Recency Tie-Break against the gov register.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Backs out the WHC-950/951/952 primary-loss (d3c0b9e4) and flat-rate-charging
(fecf4f62) changes to cert_to_inputs.py: they fire on ANY cert with those
water-heating codes, regressing the gov-API RdSAP corpus
(test_api_path_sap_accuracy_on_rdsap_21_0_1_corpus MAE 0.627 -> 0.630), and an
Opus audit found the water-only branch has a pre-existing plant-efficiency
double count they flow more kWh through. The calculator work + the correct
fix (water_eff = 1.0/(DLF*1.05)) + an Elmhurst-worksheet regression are
tracked in #1592, isolated from the extractor accuracy PR. The cylinder-
insulation MAPPER fix (f5e4814b) is retained.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Khalim-authorised MAE loosening: coding window orientation exposes the known
SAP-10.2-vs-lodged offset the zeroed solar gains were masking; within-0.5 is
the north-star metric and jumps 20.0% -> 23.9%.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
