Model/tests/domain/sap10_calculator/worksheet
Khalim Conn-Kowlessar 3e05c95e65 fix(wall-U): apply RdSAP Table 4 "Sheltered" R=0.5 to alternative walls
Audit of the API-SAP error (53% within 0.5) localised the systematic
under-rate to ELECTRIC FLATS (houses sit at 60-66% within 0.5; electric
flats 13-19%). Decomposing the flat error showed it tracks space-heating
demand per m² — the worst certs reach 130-289 kWh/m² (accurate certs sit
at 14-110), i.e. a grossly over-stated fabric heat loss, amplified ~4x by
the electricity unit price and the steep low-band SAP log curve.

Root cause: the gov-EPC API lodges `sheltered_wall="Y"` on alternative
wall sub-areas (a sub-area adjacent to an unheated buffer — stair core,
adjoining structure), but the field was dropped by the schema + domain
dataclasses and the calculator billed the alt sub-area at its full
exposed U. RdSAP 10 Table 4 (PDF p.22) "Sheltered": such a wall carries
an added external surface resistance R=0.5 m²K/W → U_sheltered =
1/(1/U + 0.5) — the SAME adjustment the main wall already applies for
`gable_wall_type=2` (`gable_wall_sheltered`,
`_SHELTERED_GABLE_ADDED_RESISTANCE_M2K_W`). Cert 0340-2976 (band-A flat,
42 m² sheltered timber-frame alt) over-stated its wall channel by
~58 W/K → walls 128 -> 70 W/K.

Threads the field end-to-end: schema dataclasses (21.0.0/21.0.1) +
domain `SapAlternativeWall.is_sheltered` (default False — the Summary/
Elmhurst path leaves it False, sheltering rides through its lodged
U-value there, so goldens are untouched) + `from_api_response` mapping
`"Y"->True` + `_alt_wall_w_per_k` applying the 0.5 resistance on the
cascade path (lodged-U and basement alt-walls return before it).

140 certs (15% of the corpus) carry a sheltered alt-wall; they under-
rated at median -0.82 / mean signed -1.33 / 23% within 0.5. Eval: 102
improved, 38 regressed (offsetting-error cases — fix is spec-uniform per
[[feedback_software_no_special_handling]]); within-0.5 53.14% -> 54.24%,
within-1.0 67.99% -> 69.64%, within-2.0 81.85% -> 83.50%, mean|err|
1.312 -> 1.248, 909 computed / 0 raises. Goldens (6035, 000565) and full
calc/epc/parser regression green; pyright net-zero.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-08 22:49:42 +00:00
..
fixtures Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
__init__.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
_elmhurst_fixtures.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
_elmhurst_worksheet_000474.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000477.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000480.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000487.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000490.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000516.py mapper: Elmhurst path populates roof_construction (int) for cross-mapper parity 2026-06-04 21:16:20 +00:00
_elmhurst_worksheet_000565.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
_elmhurst_worksheet_001431.py S0380.191: pin simulated 001431 gas-combi end-to-end at 1e-4 (e2e harness) 2026-06-02 22:44:32 +00:00
_elmhurst_worksheet_001431_6035.py S0380.195: pin sim case 4 (6035 floor geometry) e2e at 1e-4 — 6035 +19 PE is lodged divergence 2026-06-03 09:56:39 +00:00
_elmhurst_worksheet_001431_case5.py S0380.197: simulated case 5 e2e fixture — detached sandstone RR validates S0380.196 (RdSAP 10 §3.9.1 + Table 4 p.22) 2026-06-03 11:41:16 +00:00
_elmhurst_worksheet_001431_case6.py S0380.207: promote simulated case 6 to a full SapResult e2e fixture 2026-06-03 16:14:48 +00:00
_elmhurst_worksheet_001431_case7.py S0380.208: case 7 combi e2e fixture — condensing-oil-combi path validated exact 2026-06-03 17:57:22 +00:00
_elmhurst_worksheet_001431_case20.py feat(test): case-20 cascade fixture + close its CO2 via E7 per-end-use codes 2026-06-06 11:23:10 +00:00
_elmhurst_worksheet_001431_case21.py fix(u-value): solid brick as-built U by thickness — §5.7 Table 13 2026-06-06 14:40:06 +00:00
_elmhurst_worksheet_001431_rr.py S0380.193: suspended-floor (12) sealed rule fires only on a SUPPLIED U-value 2026-06-03 09:16:25 +00:00
_elmhurst_worksheet_001431_rr8.py S0380.194: pin sim case 3 (near-exact 6035 replica) e2e at 1e-4 2026-06-03 09:46:56 +00:00
_xlsx_loader.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_appendix_h_solar.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_dimensions.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_e2e_elmhurst_sap_score.py feat(test): case-20 cascade fixture + close its CO2 via E7 per-end-use codes 2026-06-06 11:23:10 +00:00
test_energy_requirements.py S0380.200: SAP 10.2 §9a two-main-heating split (203)/(205)/(207)/(213) 2026-06-03 13:09:43 +00:00
test_fabric_energy_efficiency.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_fuel_cost.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_heat_transmission.py fix(wall-U): apply RdSAP Table 4 "Sheltered" R=0.5 to alternative walls 2026-06-08 22:49:42 +00:00
test_internal_gains.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_mean_internal_temperature.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_mev.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_photovoltaic.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_rating.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_section_cascade_pins.py fix(u-value): solid brick as-built U by thickness — §5.7 Table 13 2026-06-06 14:40:06 +00:00
test_solar_gains.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_space_cooling.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_space_heating.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_utilisation_factor.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_ventilation.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00
test_water_heating.py Move sap10_calculator tests to tests/domain/sap10_calculator/ for CI 2026-06-02 16:58:00 +00:00