Model/datatypes/epc/domain
Khalim Conn-Kowlessar 48b36d3d7e fix(elmhurst-mapper): carry §7 alternative-wall "Sheltered Wall" flag
The Elmhurst Summary §7 lodges "Alternative Wall N Sheltered Wall: Yes" for
a sub-area adjacent to an unheated buffer (e.g. a flat's corridor wall),
but the extractor dropped it and _map_elmhurst_alternative_wall never set
SapAlternativeWall.is_sheltered — so the cascade billed the sub-area at its
full exposed U instead of the RdSAP 10 Table 4 (p.22) sheltered U =
1/(1/U + 0.5).

The calculator already applies is_sheltered (_alt_wall_w_per_k) and the
gov-API path already wires sheltered_wall=="Y"; this brings the Elmhurst
front-end to parity. Three-part change: AlternativeWall.sheltered field +
_alternative_walls_from_lines parse ("Alternative Wall N Sheltered Wall") +
_map_elmhurst_alternative_wall is_sheltered=a.sheltered.

Surfaced by simulated case 34 (cert 001431 electric-storage flat): the
6.02 m² corridor wall billed at full U=1.50 (9.03 W/K) instead of the
sheltered 0.86 (5.18 W/K) — +3.85 W/K, -1.61 SAP. Post-fix the alt wall
matches the worksheet's (29a) 5.177 and case 34 closes from -1.61 to -0.30
(remaining residual is a separate window/wall area-allocation thread).

Elmhurst-mapper only: API SAP gauge unchanged (57.6% within 0.5); worksheet
harness 47/47 unaffected; regression gate green (3 pre-existing fails
unrelated); pyright net-zero.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-11 07:35:46 +00:00
..
tests fix(glazing): remap divergent RdSAP-21 glazing codes 4/5 to cascade g slots 2026-06-09 10:42:16 +00:00
__init__.py fix broken imports and rename mapper class 2026-04-13 16:36:13 +00:00
epc.py added ucl corrected peui 2026-05-16 14:39:24 +00:00
epc_codes.csv slice 8a: window physics and orientation aggregates 2026-05-16 15:32:45 +00:00
epc_property_data.py fix(wall-U): apply RdSAP Table 4 "Sheltered" R=0.5 to alternative walls 2026-06-08 22:49:42 +00:00
field_mappings.py insulation thickness can be string 🟥 2026-04-15 14:26:09 +00:00
historic_epc.py demo generated for use in address2uprn 2026-05-08 14:48:15 +00:00
historic_epc_matching.py rank address similiarity 2026-05-12 16:02:01 +00:00
mapper.py fix(elmhurst-mapper): carry §7 alternative-wall "Sheltered Wall" flag 2026-06-11 07:35:46 +00:00