The sizing ladder (Vaillant aroTHERM plus 3.5-12 kW PCDB records) picks
the smallest rung whose rated output meets the design heat loss, so SAP
10.2 Appendix N reads the heat-pump efficiency near its PSR peak instead
of collapsing on an undersized fixed unit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
PropertyAudit gained three required cylinder fields; the pre-existing
divergence/goal-shortfall tests construct it via _make_audit, which
wasn't updated.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Portfolio 814 / scenario 1271 audit (2026-07-03): all 26 properties lodging
has_hot_water_cylinder with insulation type 0 (none) or NULL over-rate their
effective baseline by up to +18 SAP (avg +12.7) because
_cylinder_storage_loss_override returns None for any insulation label it
can't resolve and the worksheet keeps the zero-storage-loss combi default.
Same-lodged neighbours split by 19 effective points (WD5 0DP pids
742215/742216, both lodged 54, effective 50 vs 69) and the inflated members
distorted neighbour-divergence cohort medians (E17 6EB pid 742355 Δ+18).
New HIGH check cylinder-storage-loss-dropped fires on the deterministic
input pattern (cylinder present, insulation type ∉ {factory, loose jacket}
or thickness missing) — 28/338 on the motivating portfolio (the 26 above
plus 2 same-pattern rows with no lodged score). The calculator fix
(uninsulated Table 2 loss, or RdSAP Table 29 age-band default) is separate
follow-up work.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
`_category_for` mapped room heaters / heat pumps / heat networks but
returned None for electric-storage-heater codes (401-409), so a storage
system override emitted `sap_main_heating_code=409` +
`main_heating_category=None` while `_control_for` right beside it correctly
set the storage charge control — an asymmetry. Map storage codes to
category 7 so the overlaid cert is internally consistent (code 401-409 <->
category 7), matching the control/fuel/meter companions the overlay drags.
Consistency follow-up to the modelling HHRSH off-peak-pricing fix (#1426):
that PR's Table 12a resolver already prices any storage-coded system
off-peak regardless of category, so this is NOT a live mispricing — it
removes a latent code<->category inconsistency that other category-keyed
logic (responsiveness, pumps/fans) could trip on.
Tests: storage/HHRSH overlay tests now also assert `main_heating_category==7`.
tests/domain/epc (347) + prediction/override/reclassify (118) green; source
pyright-clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Pins the engine's baseline SAP (54) for this electric-room-heater +
gas-multipoint end-terrace ground-floor maisonette (portfolio 814 pid
742121) against accredited Elmhurst RdSAP-10 (worksheet SAP 53, within
1 point), with the Elmhurst Input Summary + SAP Worksheet PDFs saved as
evidence alongside the cert's epc.json.
Companion to the HHRSH storage-heater off-peak-pricing fix PR: this
baseline pin confirms the calculator is faithful on the as-lodged
dwelling; that PR fixes the HHRSH recommendation overlay (engine 48->73
vs Elmhurst 71).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
