Model/domain
Khalim Conn-Kowlessar fc7c4d2d3b fix(climate): compute EPC CO2/PE on the postcode demand cascade (SAP 10.2 Appendix U p.124)
The SAP/EI rating is computed on UK-average weather (Appendix U Tables
U1-U3 region 0) so ratings are nationally comparable, but Appendix U
paragraph 1 (PDF p.124) requires that "other calculations (such as for
energy use and costs on EPCs) are done using local weather. Weather data
for each postcode district are taken from the PCDB". `Sap10Calculator.
calculate` ran ONE cascade (UK-average) and fed it to SAP, CO2 AND primary
energy, so every cert's EPC-displayed CO2/PE were computed on the wrong
climate. Because most of England is warmer than the UK-average, this
systematically OVER-counted heating demand on the emissions/PE outputs.

The two cascades (`cert_to_inputs` rating, `cert_to_demand_inputs`
postcode) already existed; this wires the demand cascade into the
production entry point and grafts its CO2/PE onto the rating result (SAP
unchanged). The corpus gauge's longstanding +5% CO2/PE over-estimate was
mostly this climate bug, NOT (as previously diagnosed) per-cert mapper
fidelity:
  CO2 MAE 0.26 -> 0.12 t/yr  (bias +0.18 -> +0.04)
  PE  MAE 13.6 -> 3.8 kWh/m2 (bias +9.0  -> +0.24)
  SAP within-0.5 = 69.7% (rating cascade, unchanged)

Worksheet-validated to 1e-4 on simulated case 45 (heat-pump ground-floor
flat, postcode W6): the P960 prints the current dwelling twice — Block 1
on UK-average weather (SAP 60.5318, CO2 692.13) and Block 2 on postcode
weather (CO2 626.78, PE 6581.59). Both reproduce exactly. Added a tracked
case-45 Summary fixture + two-cascade cascade pin as a permanent guard,
and ratcheted the corpus CO2/PE ceilings to 0.13 / 4.2. The e2e Elmhurst
suite (Block-1 line refs) now pins the rating cascade directly; the two
Vaillant overlay snapshots refreshed to demand-cascade CO2/PE.

pyright not installed in this codespace (strict gate not run locally);
change is type-trivial (dataclasses.replace over SapResult).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-18 14:15:34 +00:00
..
addresses standardist Address 2026-05-22 10:13:32 +00:00
billing feat(modelling): attribute per-measure bill savings via a telescoping cascade 2026-06-03 18:01:11 +00:00
data_transformation moved classifier data transformation to an easy one 2026-06-01 14:53:34 +00:00
epc Remove EPC and asset_list changes unrelated to SAL handler 2026-06-01 16:39:09 +00:00
epc_prediction refactor(epc-prediction): PR review — rename ComparableProperty, relocate PredictionTarget 2026-06-16 13:34:44 +00:00
fuel_rates feat(fuel-rates): FuelRates snapshot + repository foundation (ADR-0014) 2026-06-02 09:29:07 +00:00
geospatial feat(geospatial): one-read spatial reference (coords + restrictions) 2026-06-04 17:13:39 +00:00
magicplan add todo comment for named ranges 2026-06-10 13:32:11 +00:00
modelling feat(modelling): drive measure scoping from the Scenario's exclusions 2026-06-16 15:26:25 +00:00
property feat(epc-prediction): slice-5a predicted source path on Property 2026-06-16 03:33:47 +00:00
property_baseline feat(baseline): sap_code_to_fuel normalizes via the calculator's own helper 2026-06-05 18:59:25 +00:00
sap10_calculator fix(climate): compute EPC CO2/PE on the postcode demand cascade (SAP 10.2 Appendix U p.124) 2026-06-18 14:15:34 +00:00
sap10_ml fix(uvalues): apply §5.8 insulation R to stone walls (RdSAP 10 p.41-42) 2026-06-17 00:26:25 +00:00
tasks added postcode splitter rewrite to ddd 2026-05-19 16:35:09 +00:00
building_geometry.py feat(modelling): floor Recommendation Generator + ground-floor-area geometry 2026-06-03 09:12:29 +00:00
postcode.py get rid of comments 2026-05-20 13:21:11 +00:00