Third Playwright-entry error found via input reconciliation: my build left
draught-proofed doors at 0 (Elmhurst computed 33% draught proofing), but the
cert lodges percent_draughtproofed=100. Our calculator correctly uses 100% ->
infiltration 42.66 W/K; the ~19 W/K ventilation gap to Elmhurst was purely my
build error. On matched inputs our fabric+TB (109.38) equals Elmhurst's total
fabric (37) EXACTLY, confirming the calculator is RdSAP-faithful. Committed for
build-faithfulness record; the engine's +1.24 vs lodged 76 is not a bug.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Input reconciliation (Elmhurst summary vs EpcPropertyData vs raw cert) exposed
two Playwright-entry errors: lighting entered as 6 incandescent (cert has 5 LED,
100% low-energy) and wall thickness left at Elmhurst's 260mm default (cert lodges
400mm). Fixing both moved Elmhurst 67->69. Confirmed the MAPPER is faithful
(every fabric/heating/lighting field matches the raw cert) and the engine uses
the correct PCDB 18908 efficiency (88.7%). The remaining Elmhurst gap to lodged
76 is the un-enterable PCDB boiler (automation falls back to generic BGW 84% +
keep-hot); the engine (77) is faithful. Not a mapping error.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2-storey semi, solid brick 400mm with EXTERNAL insulation, 300mm loft,
suspended uninsulated ground floor, gas combi, double glazing (glazed_type 13).
Built in accredited Elmhurst RdSAP10: roof (U 0.14, 5.459 W/K) and windows
(15.32 x eff U 1.3258 = 20.311 W/K) match the engine EXACTLY; the
externally-insulated wall is engine U 0.29 vs Elmhurst 0.30, validating the
slice-5 external-insulation default (100mm added over solid brick); suspended
ground floor engine 0.68 vs Elmhurst 0.70. Elmhurst's overall SAP 67 is not
comparable (reused-assessment Standard-Combi keep-hot loss, a build artifact).
Engine 77 vs lodged 76 (within 1.24). Pinned to the observed 77.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
