§6 slice 7: delete legacy _solar_gains_w + WindowInput + _window_inputs

Removes:
  - calculator.WindowInput dataclass
  - calculator.CalculatorInputs.windows field
  - calculator._solar_gains_w function
  - cert_to_inputs._window_inputs / _g_perpendicular / _frame_factor
  - cert_to_inputs._G_PERPENDICULAR_BY_GLAZING_TYPE / _FRAME_FACTOR_BY_MATERIAL
    / _ORIENTATION_BY_CODE lookup tables (duplicated, spec-correct versions
    live in solar_gains.py)
  - 3 obsolete tests in test_cert_to_inputs.py that probed deleted internals;
    one asserted the spec-incorrect Metal frame factor 0.83 (Table 6c spec
    value is 0.8).

Test fixtures in test_calculator.py + test_bre_worked_examples.py pin the
prior synthetic solar 12-tuple verbatim so heat-balance numerics stay
identical pre/post §6 wiring.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packages/domain/src/domain/sap/calculator.py

@@ -50,11 +50,6 @@ from domain.sap.worksheet.rating import (
     sap_rating,
     sap_rating_integer,
 )
-from domain.sap.worksheet.solar_gains import (
-    Orientation,
-    surface_solar_flux_w_per_m2,
-    window_solar_gain_w,
-)
 from domain.sap.worksheet.space_heating import monthly_heat_requirement_kwh
 from domain.sap.worksheet.utilisation_factor import utilisation_factor
 
@@ -65,22 +60,6 @@ _TIME_CONSTANT_DIVISOR_KJ_TO_WH: Final[float] = 3.6
 _ETA_ITERATIONS: Final[int] = 2
 
 
-@dataclass(frozen=True)
-class WindowInput:
-    """One glazed opening contributing solar gain. Orientation maps to a
-    Table U5 column and to Table U4 latitude via `surface_solar_flux_w_per_m2`.
-    `g_perpendicular`, `frame_factor`, `overshading_factor` come from
-    Tables 6b/6c/6d — supplied by the caller so this module remains
-    physics-only."""
-
-    area_m2: float
-    orientation: Orientation
-    pitch_deg: float
-    g_perpendicular: float
-    frame_factor: float
-    overshading_factor: float
-
-
 @dataclass(frozen=True)
 class CalculatorInputs:
     """Synthetic SAP 10.3 calculator inputs. The cert→inputs mapper
@@ -110,7 +89,6 @@ class CalculatorInputs:
     # only indexes into it per month, no recomputation here.
     solar_gains_monthly_w: tuple[float, ...]
     region: int
-    windows: tuple[WindowInput, ...]
     control_type: int
     responsiveness: float
     living_area_fraction: float
@@ -185,27 +163,6 @@ class SapResult:
     intermediate: dict[str, float]
 
 
-def _solar_gains_w(
-    *, windows: tuple[WindowInput, ...], region: int, month: int
-) -> float:
-    total = 0.0
-    for w in windows:
-        s = surface_solar_flux_w_per_m2(
-            orientation=w.orientation,
-            pitch_deg=w.pitch_deg,
-            region=region,
-            month=month,
-        )
-        total += window_solar_gain_w(
-            area_m2=w.area_m2,
-            surface_flux_w_per_m2=s,
-            g_perpendicular=w.g_perpendicular,
-            frame_factor=w.frame_factor,
-            overshading_factor=w.overshading_factor,
-        )
-    return total
-
-
 def _time_constant_h(*, tmp_kj_per_m2_k: float, tfa_m2: float, hlc_w_per_k: float) -> float:
     if hlc_w_per_k <= 0:
         return float("inf")

packages/domain/src/domain/sap/rdsap/cert_to_inputs.py

@@ -52,7 +52,7 @@ from domain.ml.sap_efficiencies import (
     seasonal_efficiency,
     water_heating_efficiency as _legacy_water_heating_efficiency,
 )
-from domain.sap.calculator import CalculatorInputs, WindowInput
+from domain.sap.calculator import CalculatorInputs
 from domain.sap.tables.table_12 import (
     co2_factor_kg_per_kwh,
     primary_energy_factor,
@@ -67,7 +67,7 @@ from domain.sap.worksheet.heat_transmission import (
     DwellingExposure,
     heat_transmission_from_cert,
 )
-from domain.sap.worksheet.solar_gains import Orientation, solar_gains_from_cert
+from domain.sap.worksheet.solar_gains import solar_gains_from_cert
 from domain.sap.worksheet.ventilation import (
     MechanicalVentilationKind,
     ventilation_from_inputs,
@@ -88,56 +88,6 @@ _LIVING_AREA_FRACTION_DEFAULT: Final[float] = 0.21
 _LIVING_AREA_FRACTION_MIN: Final[float] = 0.13
 
 
-# SAP10 octant code → solar_gains.Orientation. Codes 1-8 only; anything
-# else (0, "NR", arbitrary string) is treated as un-mapped and the window
-# contributes no solar gain.
-_ORIENTATION_BY_CODE: Final[dict[int, Orientation]] = {
-    1: Orientation.N,
-    2: Orientation.NE,
-    3: Orientation.E,
-    4: Orientation.SE,
-    5: Orientation.S,
-    6: Orientation.SW,
-    7: Orientation.W,
-    8: Orientation.NW,
-}
-
-
-# SAP 10.3 Table 6b — g_perpendicular (solar transmittance at normal
-# incidence) by SAP10 glazing_type code. Default 0.72 (modern double
-# glazing, no low-E) when the cert's glazing_type is missing or
-# unrecognised — the modal RdSAP case.
-_G_PERPENDICULAR_BY_GLAZING_TYPE: Final[dict[int, float]] = {
-    1: 0.85,  # single
-    2: 0.72,  # double 2002-2022 (no low-E)
-    3: 0.72,  # double pre-2002
-    4: 0.63,  # double low-E soft coat
-    5: 0.76,  # secondary glazing
-    6: 0.68,  # triple
-}
-_G_PERPENDICULAR_DEFAULT: Final[float] = 0.72
-
-
-# SAP 10.3 Table 6c — frame factor (proportion of window area that is
-# glazed, not frame) by frame material. The cert lodges this as a free-
-# text string ("PVC", "Wood", "Metal", "Aluminium"); matching is case-
-# insensitive and substring-based because site-notes capitalisation
-# drifts.
-_FRAME_FACTOR_BY_MATERIAL: Final[tuple[tuple[str, float], ...]] = (
-    ("metal with thermal break", 0.80),
-    ("metal", 0.83),
-    ("aluminium with thermal break", 0.80),
-    ("aluminium", 0.83),
-    ("steel", 0.83),
-    ("wood", 0.70),
-    ("timber", 0.70),
-    ("pvc", 0.70),
-    ("upvc", 0.70),
-    ("composite", 0.70),
-)
-_FRAME_FACTOR_DEFAULT: Final[float] = 0.70
-
-
 _PENCE_TO_GBP: Final[float] = 0.01
 _DEFAULT_THERMAL_MASS_PARAMETER_KJ_PER_M2_K: Final[float] = 250.0
 _DEFAULT_PUMPS_FANS_KWH_PER_YR: Final[float] = 130.0
@@ -363,59 +313,6 @@ def _living_area_fraction(habitable_rooms_count: Optional[int]) -> float:
     return _LIVING_AREA_FRACTION_MIN
 
 
-def _g_perpendicular(w: SapWindow) -> float:
-    """Solar transmittance at normal incidence per SAP 10.3 Table 6b.
-    Prefer the cert's measured value (`window_transmission_details`);
-    otherwise look up by `glazing_type`."""
-    if w.window_transmission_details is not None:
-        return float(w.window_transmission_details.solar_transmittance)
-    if isinstance(w.glazing_type, int) and w.glazing_type in _G_PERPENDICULAR_BY_GLAZING_TYPE:
-        return _G_PERPENDICULAR_BY_GLAZING_TYPE[w.glazing_type]
-    return _G_PERPENDICULAR_DEFAULT
-
-
-def _frame_factor(w: SapWindow) -> float:
-    """SAP 10.3 Table 6c frame factor. Prefer the cert's measured value
-    (`SapWindow.frame_factor`); otherwise look up by `frame_material`."""
-    if w.frame_factor is not None:
-        return float(w.frame_factor)
-    material = (w.frame_material or "").lower()
-    for needle, ff in _FRAME_FACTOR_BY_MATERIAL:
-        if needle in material:
-            return ff
-    return _FRAME_FACTOR_DEFAULT
-
-
-def _window_inputs(windows: list[SapWindow]) -> tuple[WindowInput, ...]:
-    """Map each cert window with a known SAP octant to a `WindowInput`.
-
-    `g_perpendicular` follows SAP 10.3 Table 6b (by glazing_type when no
-    measured transmission details), `frame_factor` follows Table 6c (by
-    frame_material when no measured value). Overshading factor stays at
-    SAP's "average" default 0.77 because the cert doesn't lodge a per-
-    window overshading code in RdSAP 10. Pitch = 90° (vertical windows).
-    Windows whose orientation isn't in 1-8 are dropped, matching the
-    live ML feature-builder convention.
-    """
-    out: list[WindowInput] = []
-    for w in windows:
-        orientation_code = w.orientation if isinstance(w.orientation, int) else None
-        if orientation_code is None or orientation_code not in _ORIENTATION_BY_CODE:
-            continue
-        area = float(w.window_width) * float(w.window_height)
-        out.append(
-            WindowInput(
-                area_m2=area,
-                orientation=_ORIENTATION_BY_CODE[orientation_code],
-                pitch_deg=90.0,
-                g_perpendicular=_g_perpendicular(w),
-                frame_factor=_frame_factor(w),
-                overshading_factor=0.77,
-            )
-        )
-    return tuple(out)
-
-
 def _window_total_area_and_avg_u(windows: list[SapWindow]) -> tuple[float, Optional[float]]:
     """Area-weighted total + U-value for the conduction worksheet."""
     if not windows:
@@ -1009,7 +906,6 @@ def cert_to_inputs(
             overshading=_INTERNAL_GAINS_DEFAULT_OVERSHADING,
         ).total_solar_gains_monthly_w,
         region=_region_index(epc.region_code),
-        windows=_window_inputs(epc.sap_windows),
         control_type=_control_type(main),
         responsiveness=_responsiveness(main),
         living_area_fraction=_living_area_fraction(epc.habitable_rooms_count),

packages/domain/src/domain/sap/rdsap/tests/test_cert_to_inputs.py

@@ -29,7 +29,6 @@ from domain.ml.tests._fixtures import (
 )
 from domain.sap.calculator import Sap10Calculator, SapResult
 from domain.sap.rdsap.cert_to_inputs import cert_to_inputs
-from domain.sap.worksheet.solar_gains import Orientation
 
 
 def _gas_boiler_detail(sap_main_heating_code: int = 102) -> MainHeatingDetail:
@@ -319,22 +318,6 @@ def test_calculator_always_uses_uk_average_weather_for_rating() -> None:
     assert inputs_default.region == 0
 
 
-def test_window_orientation_codes_map_to_solar_gains_orientation_enum() -> None:
-    # Arrange — SAP10 octant codes 1-8 (1=N, 5=S) must surface in the
-    # mapped WindowInput list as the matching `Orientation` enum members.
-    base = _typical_semi_detached_epc()
-
-    # Act
-    inputs = cert_to_inputs(base)
-
-    # Assert — south + north window from the fixture both land.
-    orientations = {w.orientation for w in inputs.windows}
-    assert orientations == {Orientation.S, Orientation.N}
-    south = next(w for w in inputs.windows if w.orientation == Orientation.S)
-    assert south.area_m2 == 2.0 * 1.2  # width × height from fixture
-    assert south.pitch_deg == 90.0
-
-
 def test_open_chimneys_raise_infiltration_ach() -> None:
     # Arrange — Direction check: chimneys add Table 2.1 volume to the
     # infiltration calc, so an otherwise identical dwelling with 2 open
@@ -464,42 +447,6 @@ def test_main_heating_control_code_maps_to_sap_control_type() -> None:
     assert type_3.control_type == 3
 
 
-def test_window_g_perpendicular_uses_table_6b_by_glazing_type() -> None:
-    # Arrange — SAP 10.3 Table 6b: g⊥ depends on the glazing type when
-    # transmission details aren't measured. Single (code 1) → 0.85;
-    # double low-E soft coat (code 4) → 0.63; triple (code 6) → 0.68.
-    single = make_window(orientation=5, glazing_type=1, frame_material="PVC")
-    triple = make_window(orientation=5, glazing_type=6, frame_material="PVC")
-    low_e_double = make_window(orientation=5, glazing_type=4, frame_material="PVC")
-    base = _typical_semi_detached_epc()
-    base.sap_windows = [single, triple, low_e_double]
-
-    # Act
-    inputs = cert_to_inputs(base)
-
-    # Assert — same orientation, three different glazing types.
-    g_values = sorted(w.g_perpendicular for w in inputs.windows)
-    assert g_values == [0.63, 0.68, 0.85]
-
-
-def test_window_frame_factor_uses_table_6c_by_frame_material() -> None:
-    # Arrange — Table 6c: PVC/Wood = 0.70; aluminium / steel = 0.83
-    # (no thermal break). Metal-with-thermal-break would be 0.80 but
-    # not tested here since cert strings rarely carry that distinction.
-    pvc = make_window(orientation=5, frame_material="PVC")
-    wood = make_window(orientation=5, frame_material="Wood")
-    aluminium = make_window(orientation=5, frame_material="Aluminium")
-    base = _typical_semi_detached_epc()
-    base.sap_windows = [pvc, wood, aluminium]
-
-    # Act
-    inputs = cert_to_inputs(base)
-
-    # Assert
-    ff_values = sorted(w.frame_factor for w in inputs.windows)
-    assert ff_values == [0.70, 0.70, 0.83]
-
-
 def test_off_peak_meter_routes_electric_costs_to_low_rate() -> None:
     # Arrange — RdSAP rule (per S-B15): we trust the cert's lodged
     # meter_type as the tariff source of truth. SAP10 code 2 = off-peak

packages/domain/src/domain/sap/tests/test_bre_worked_examples.py

@@ -25,13 +25,10 @@ import pytest
 
 from domain.sap.calculator import (
     CalculatorInputs,
-    WindowInput,
-    _solar_gains_w,
     calculate_sap_from_inputs,
 )
 from domain.sap.worksheet.dimensions import Dimensions
 from domain.sap.worksheet.heat_transmission import HeatTransmission
-from domain.sap.worksheet.solar_gains import Orientation
 
 
 def _baseline_dwelling() -> CalculatorInputs:
@@ -63,34 +60,19 @@ def _baseline_dwelling() -> CalculatorInputs:
         total_external_element_area_m2=200.0,  # synthetic placeholder
         total_w_per_k=150.0,
     )
-    windows = (
-        WindowInput(
-            area_m2=4.0,
-            orientation=Orientation.S,
-            pitch_deg=90.0,
-            g_perpendicular=0.63,
-            frame_factor=0.7,
-            overshading_factor=0.77,
-        ),
-        WindowInput(
-            area_m2=4.0,
-            orientation=Orientation.N,
-            pitch_deg=90.0,
-            g_perpendicular=0.63,
-            frame_factor=0.7,
-            overshading_factor=0.77,
-        ),
-    )
     return CalculatorInputs(
         dimensions=dim,
         heat_transmission=ht,
         monthly_infiltration_ach=(0.7,) * 12,
         internal_gains_monthly_w=(450.0,) * 12,
-        solar_gains_monthly_w=tuple(
+        # Hand-computed solar (S + N 4 m² panes, g⊥=0.63 FF=0.7 Z=0.77,
-            _solar_gains_w(windows=windows, region=0, month=m) for m in range(1, 13)
+        # UK-avg region 0, vertical) — captured at HEAD so the trace fixture
+        # matches the pre-§6-wiring numerical baseline.
+        solar_gains_monthly_w=(
+             70.1510, 118.4419, 161.4420, 202.5589, 231.7608, 232.9177,
+            223.3279, 200.6543, 175.3023, 130.5274,  83.7805,  60.2212,
         ),
         region=0,
-        windows=windows,
         control_type=2,
         responsiveness=1.0,
         living_area_fraction=0.30,

packages/domain/src/domain/sap/tests/test_calculator.py

@@ -23,13 +23,10 @@ import pytest
 from domain.sap.calculator import (
     CalculatorInputs,
     SapResult,
-    WindowInput,
-    _solar_gains_w,
     calculate_sap_from_inputs,
 )
 from domain.sap.worksheet.dimensions import Dimensions
 from domain.sap.worksheet.heat_transmission import HeatTransmission
-from domain.sap.worksheet.solar_gains import Orientation
 
 
 def _baseline_inputs() -> CalculatorInputs:
@@ -59,24 +56,6 @@ def _baseline_inputs() -> CalculatorInputs:
         total_external_element_area_m2=200.0,  # synthetic placeholder
         total_w_per_k=150.0,
     )
-    windows = (
-        WindowInput(
-            area_m2=4.0,
-            orientation=Orientation.S,
-            pitch_deg=90.0,
-            g_perpendicular=0.63,
-            frame_factor=0.7,
-            overshading_factor=0.77,
-        ),
-        WindowInput(
-            area_m2=4.0,
-            orientation=Orientation.N,
-            pitch_deg=90.0,
-            g_perpendicular=0.63,
-            frame_factor=0.7,
-            overshading_factor=0.77,
-        ),
-    )
     return CalculatorInputs(
         dimensions=dim,
         heat_transmission=ht,
@@ -85,11 +64,15 @@ def _baseline_inputs() -> CalculatorInputs:
         # per-month variation lives in §5 orchestrator output; tracer
         # tests don't need the modulation to verify the SAP loop.
         internal_gains_monthly_w=(450.0,) * 12,
-        solar_gains_monthly_w=tuple(
+        # Hand-computed solar (S + N 4 m² panes, g⊥=0.63 FF=0.7 Z=0.77,
-            _solar_gains_w(windows=windows, region=0, month=m) for m in range(1, 13)
+        # UK-avg region 0, vertical) — captured from §6 leaves at HEAD
+        # so this synthetic baseline keeps the same heat-balance gains
+        # as before the §6 wiring slice.
+        solar_gains_monthly_w=(
+             70.1510, 118.4419, 161.4420, 202.5589, 231.7608, 232.9177,
+            223.3279, 200.6543, 175.3023, 130.5274,  83.7805,  60.2212,
         ),
         region=0,
-        windows=windows,
         control_type=2,
         responsiveness=1.0,
         living_area_fraction=0.30,