SAP 10.2 Table 5a (PDF p.177) row "Warm air heating system fans
a) c)" computes the gain as SFP × 0.04 × V (W). Footnote c) sets
the default SFP to 1.5 W/(l/s) when no PCDB warm-air-unit record
is lodged; footnote a) applies the heating-season-only mask
(zero in summer months). Footnote c) further omits the gain when
the dwelling has balanced whole-house mechanical ventilation
(MVHR / MV) — same omission as the Table 4f kWh-side footnote e).
Pre-slice the cascade's `internal_gains_from_cert` only wired the
central-heating-pump row of Table 5a; the warm-air-fan gain helper
(`warm_air_heating_fan_w`) existed but was unwired. The kWh-side
parallel (Table 4f, 136.35 kWh/yr) was wired in S0380.158 — this
slice closes the symmetry on the gain side.
Per-line walk on electric 2 (SAP code 524 = Cat 5 ASHP with
warm-air distribution, V = 227.25 m³, no balanced MV):
worksheet (70)[Jan] = 13.6350 W
cascade (70)[Jan] = 0.0000 W delta = -13.635 W
worksheet (98c)[Jan] = 1600.43 kWh
cascade (98c)[Jan] = 1608.12 kWh delta = +7.69 kWh
13.635 W = 1.5 × 0.04 × 227.25 exactly. The -13.6 W winter gain
shortfall propagates through the §7 utilisation cascade and over-
states cascade SH demand by ~57 kWh/yr (cascade 9483 vs worksheet
9426), under-charging cost by ~£2.50 with opposite sign to the
S0380.156-.158 closures.
Fix: new `_any_main_system_has_warm_air_distribution(epc)` +
`_has_balanced_mechanical_ventilation(epc)` predicates in
`internal_gains.py`, mirroring `cert_to_inputs._TABLE_4A_WARM_AIR_SAP_CODES`
+ `_BALANCED_MV_KIND_NAMES` (kept here as siblings so the worksheet
layer stays free of rdsap deps). Orchestrator wires
`warm_air_heating_fan_w(sfp=1.5, dwelling_volume_m3)` into the
heating-season term of `pumps_fans_monthly_w` when warm-air
distribution is present and balanced MV is not.
Closures electric 2:
ΔSAP_c -0.1087 → -0.0000 EXACT
Δcost +£2.50 → -£0.00 EXACT
ΔCO2 +16.54 → +11.95 (joins lighting-PE deferred cohort)
ΔPE +97.69 → +48.66 (joins lighting-PE deferred cohort)
Electric 2 joins the 15-variant lighting-PE deferred cohort
(electric 1 + electric 3/5/6/7/8/9 + solid fuel 5/6/7/8 + solid
fuel 4/9/10/11 + electric 2) where SAP/cost are EXACT but PE/CO2
carry an Elmhurst-vs-spec MONTHLY-factor offset (cohort uses
Table 12 annual factors on the off-peak HW immersion line; spec
mandates Table 12d/12e monthly per the header).
Verbatim spec quote (SAP 10.2 Table 5a row "Warm air heating
system fans a) c)", PDF p.177):
"Warm air heating system fans a) c) SFP × 0.04 × V"
Footnote c): "SFP is the specific fan power from the database
record for the warm air unit if applicable; otherwise
1.5 W/(l/s). These values of SFP include an in-use factor.
If the heating system is a warm air unit and there is balanced
whole house mechanical ventilation, the gains for the warm air
system should not be included."
Footnote a): "... Set to zero in summer months. ..."
Σ |ΔSAP_c| across 25-variant cohort: 0.18 → 0.07 (~60% reduction).
No regressions on the other 24 variants or any golden fixture —
gate keyed on Table 4a warm-air SAP code frozenset (only electric
2 in the corpus has a code in that set).
Tests: 905 pass (+1), 0 fail. Pyright net-zero (35 → 35).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
SAP 10.2 Table 5a (PDF p.177) row "Central heating pump in heated
space" only applies to mains with a water-loop circulation pump.
Footnote a) names two exclusions verbatim ("Does not apply if a
heating system used solely for domestic hot water. ... Not applicable
for electric heat pumps from database."), and the row's name carries
the implicit third: dry mains with no central heating pump (electric
storage heaters, electric direct-acting, solid-fuel room heaters
without back-boilers) — the row simply doesn't list them.
Pre-slice `internal_gains_from_cert` gated only on Note a) (HP
exclusion), applying `central_heating_pump_w(date_category=...)` to
every non-HP main. The default UNKNOWN-date branch added 7 W of pump
gain to (70)m for every dry-system fixture in the controlled-variable
corpus, even though the worksheet (70)m = 0 every month.
Per-line walk on electric 3 (SAP code 401 "Manual charge control"):
cascade (73)[Jan] = 640.21 W
worksheet (73)[Jan] = 633.21 W delta = +7.00 W
cascade (70)[Jan] = 7.00 W
worksheet (70)[Jan] = 0.00 W Table 5a inapplicable
The +7 W winter-month gain lowered cascade SH demand by ~38 kWh/yr
(cascade 11050 vs worksheet 11088). At Table 32 18-hour low-rate
~7.4 p/kWh that's £2.50/yr under-charging — matching the cluster's
uniform Δcost = -£1.96..-£2.80 pattern. Continuous SAP rose ~+0.10
because cost dominates the ECF.
Fix: new `_any_main_system_has_central_heating_pump(epc)` predicate
in `internal_gains.py`, mirroring `cert_to_inputs._is_wet_boiler_main`
(S0380.149 — Table 4f kWh side). Wet if any non-HP main lodges:
- sap_main_heating_code in {101-141, 151-161, 191-196} (gas/oil/
solid-fuel/electric boilers per Table 4a/4b),
- main_heating_index_number (PCDB Table 322 record),
- main_heating_category in {1, 2} (RdSAP central heating), OR
- heat_emitter_type in {1, 3} (radiators / fan-coil per Table 4d).
Dead `_all_main_systems_are_heat_pumps` helper removed (the new
predicate subsumes its role).
Cluster closures (10 variants):
electric 3: SAP +0.1215 → -0.0000, cost -£2.80 → -£0.00
electric 5: SAP +0.1081 → -0.0000, cost -£2.49 → -£0.00
electric 6: SAP +0.1081 → -0.0000, cost -£2.49 → -£0.00
electric 7: SAP +0.1017 → -0.0000, cost -£2.34 → -£0.00
electric 8: SAP +0.0941 → -0.0000, cost -£2.17 → -£0.00
electric 9: SAP +0.1199 → -0.0000, cost -£2.76 → -£0.00
solid fuel 4: SAP +0.0850 → -0.0000, cost -£1.96 → -£0.00
solid fuel 9: SAP +0.1072 → -0.0000, cost -£2.47 → -£0.00
solid fuel 10: SAP +0.1134 → +0.0000, cost -£2.61 → -£0.00
solid fuel 11: SAP +0.0912 → +0.0000, cost -£2.10 → +£0.00
Σ |ΔSAP_c| across 25-variant cohort: 1.24 → 0.18. All 10 cluster
variants now join the lighting-PE +48.66 / CO2 +11.95 deferred
cohort (Elmhurst-vs-spec monthly factor quirk, same shape as
electric 1 + solid fuel 5/6/7/8 from prior closures).
Verbatim spec quote (SAP 10.2 Table 5a row 1, PDF p.177):
"Central heating pump in heated space, 2013 or later 3 a)"
"Central heating pump in heated space, 2012 or earlier 10 a)"
"Central heating pump in heated space, unknown date 7 a)"
The row name ("Central heating pump") gates by construction: dry
systems have no central heating pump and the row's three sub-rows
don't apply.
No regressions on the other 31 variants or any golden fixture; the
6 Elmhurst U985 fixtures lodge PCDB index → the new predicate
returns True → pump_w unchanged.
Tests: 904 pass (+1), 0 fail. Pyright net-zero (35 → 35).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Captures the per-line walk discipline used to close electric 2 + 5
across four slices (.156 Table 3 WHC=903 primary-loss, .157 Table 2b
note b) WHC=903 ×0.9, .158 Table 4f warm-air heating fans, .159
Table 4a Cat 7 R tariff-aware dispatch). Σ |ΔSAP_c| across the
25-variant heating-systems corpus dropped from 2.87 → 1.21 (58%
reduction). All variants now sit under 0.3 SAP.
Next-slice candidate: the 9-variant cluster at ±0.09..0.12 SAP
(electric 3/5/6/7/8/9 + sf 4/9/10/11) — uniform pattern suggesting
a shared shave-the-residual fix. Worth a per-line walk on one
cluster variant before accepting the prior "Elmhurst-vs-spec quirk"
framing.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
SAP 10.2 Table 4a (PDF p.166) Cat 7 "Electric storage heaters"
splits the responsiveness R between two sub-tables:
Off-peak tariff:
Slimline storage heaters ... R = 0.2 402
Convector storage heaters ... R = 0.2 403
Slimline + Celect-type control ... R = 0.4 405
Convector + Celect-type ctrl ... R = 0.4 406
24-hour heating tariff:
Slimline storage heaters ... R = 0.4 402
Convector storage heaters ... R = 0.4 403
Slimline + Celect-type control ... R = 0.6 405
Convector + Celect-type ctrl ... R = 0.6 406
Per SAP 10.2 §12.4.3 (PDF p.36) the 18-hour tariff has electricity
at low rate for 18 hours per day with at most 6h of interruption /
2h max each — operationally equivalent to 24-hour for storage-heater
charging. The cascade therefore routes EIGHTEEN_HOUR + TWENTY_FOUR_
HOUR through the 24-hour Table 4a sub-row.
Pre-slice `_responsiveness` keyed on `sap_main_heating_code` only
and returned R=0.2 for code 402 regardless of tariff. The existing
docstring already flagged the gap:
402: 0.20, # Slimline storage heaters (24-hr tariff: 0.40)
... "promote to (sap_code, tariff) lookup when 24-hour fixture
surfaces; until then the off-peak default applies (under-shoots
R for the 24-hour case)."
Per-line walk on electric 5 (sap_main_heating_code=402 +
meter_type="18 Hour"): cascade T_living (87)[Jan] = 20.1213 vs
worksheet 19.6519, (92)[Jan] = 18.6996 vs worksheet 18.2063, (93)
[Jan] = 19.0996 vs worksheet 18.6063 (cascade +0.4933 K throughout
the cascade). Back-solve from worksheet T_living=19.6519 via the
Table 9b Tsc formula:
Tsc(R=0.4) = 0.6 × (21-2) + 0.4 × (4.3 + 0.9933 × 705.4/210.23)
= 11.4 + 0.4 × 7.6325 = 14.4528
ΔT = 21 - 14.4528 = 6.5472
u_sum = 0.5 × 6.5472 × (7² + 8²) / (24 × 11.43) = 1.3481
T_living = 21 - 1.3481 = 19.6519 EXACT match.
Adds:
- `_CONTINUOUS_CHARGING_TARIFFS: frozenset[Tariff]` = {EIGHTEEN_
HOUR, TWENTY_FOUR_HOUR} — the tariffs treated as "24-hour
heating" for Table 4a R selection.
- `_RESPONSIVENESS_24_HOUR_OVERRIDE_BY_SAP_CODE: dict[int, float]`
— the override table for codes 402/403/405/406 (404, 407, 409
keep the same R in both sub-tables).
- `tariff: Optional[Tariff]` parameter to `_responsiveness`, with
the override consulted before the off-peak default.
- Tariff threaded through both call sites of MIT cascade (rating
+ demand paths) via `tariff_from_meter_type`.
Closures electric 5:
ΔSAP −1.1759 → +0.1081 (91% reduction)
Δcost +£27.09 → −£2.49
ΔCO2 +62.72 → +7.30 kg
ΔPE +438.03 → +0.07 kWh (essentially EXACT)
Electric 5 now joins the same residual cluster as electric 3/6/7/8/
9 (+0.09..+0.12 SAP, −£2..−£3 cost, +£7 CO2) — the cluster that
the prior handovers suspected was a shared shave-the-residual gap.
No regressions on the other 24 cohort variants. Extended handover
suite: 903 pass / 0 fail (was 902 — +1 from the new AAA test).
Pyright net-zero (43 → 43).
Σ |ΔSAP_c| across the 25-variant cohort: 2.30 → 1.24 (~46%
reduction from this slice).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
SAP 10.2 Table 4f (PDF p.174) row "Warm air heating system fans"
+ footnote e) — verbatim:
Warm air heating system fans e) SFP × 0.4 × V
e) SFP is the specific fan power from the database record for the
warm air unit if applicable; otherwise 1.5 W/(l/s). These values
of SFP include the in-use factor.
If the heating system is a warm air unit and there is balanced
whole house mechanical ventilation, the electricity for warm
air circulation should not be included in addition to the
electricity for mechanical ventilation. However it is included
for a warm air system and MEV or PIV from outside.
V is the volume of the dwelling in m³.
Per Table 4a (PDF p.165-166), warm-air systems are:
- Category 5: heat pumps with warm-air distribution (codes 521,
523, 524 electric; 525, 526, 527 gas-fired)
- Category 9: warm-air systems NOT heat pump (501-511, 520 gas-
fired; 512-514 liquid-fired; 515 Electricaire electric)
Pre-slice the cascade's `_table_4f_additive_components` docstring
explicitly listed "(230b) Warm-air heating fans + (230c) for warm-
air pump" as "Not yet wired" — every Cat 5 / Cat 9 warm-air corpus
variant resolved `pumps_fans_kwh_per_yr` to 0. For electric 2 (code
524 Cat 5 air-source warm-air HP, no MV, V = 227.25 m³), the P960
worksheet block 11a (249) lodges 136.35 kWh × 13.67 p/kWh = £18.64
where the cascade computed 0.
New `_TABLE_4A_WARM_AIR_SAP_CODES` frozenset (22 codes) + leaf helper
`_table_4f_warm_air_heating_fans_kwh(main, dwelling_volume_m3,
has_balanced_mv)` wired at the orchestrator pumps_fans summation
alongside the existing circulation-pump and gas-flue-fan helpers.
Footnote-e balanced-MV omission reads `epc.sap_ventilation.
mechanical_ventilation_kind` via the new
`_has_balanced_mechanical_ventilation` predicate (returns True for
MVHR / MV; False for MEV / PIV / NATURAL).
Per-line walk evidence: cascade `pumps_fans_kwh_per_yr` = 0.0000 vs
worksheet (249) = 136.3500 = 1.5 × 0.4 × 227.25 exactly. Default SFP
from footnote e matches; PCDB warm-air-unit SFP lookup deferred
until a fixture exercises it.
Closures electric 2:
pumps_fans_kwh_per_yr: 0 → 136.35 (EXACT match to worksheet)
ΔSAP +0.7002 → −0.1087 (residual swung past worksheet — the +0.70
pre-slice was an under-counted-fan offset; spec-correct fix lands
just past zero, exposing a small upstream SH cascade gap likely
in the Cat 5 warm-air HP Table 4a SH efficiency or Table 9c MIT
cascade for warm-air mains — follow-up slice)
Δcost −£16.14 → +£2.50
ΔCO2 −2.37 → +16.54 kg
ΔPE −108.58 → +97.69 kWh
No regressions on the other 24 cohort variants — the warm-air-code
gate fires only when `sap_main_heating_code` is in the new frozenset
and only electric 2 has a warm-air SAP code in the corpus. Extended
handover suite: 902 pass / 0 fail (was 901 — +1 from the new AAA
test). Pyright net-zero (43 → 43).
Σ |ΔSAP_c| across the 25-variant cohort: 2.87 → 2.30 (~20%
reduction from this slice).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
SAP 10.2 Table 2b note b) (PDF p.159) — verbatim:
Multiply Temperature Factor by 0.9 if there is separate time
control of domestic hot water (boiler systems, warm air systems
and heat pump systems).
The parenthetical list restricts the rule to systems where the heat
generator (boiler / warm-air / HP) is the device heating the
cylinder. Electric immersion is NOT in that list because the
immersion isn't a heat-generator system feeding DHW — it sits inside
the cylinder. The ×0.9 multiplier reflects shorter cylinder-heating
periods when a boiler / HP / warm-air operates on a separate timer
for DHW vs SH; if the heat generator doesn't feed the cylinder at all
(because the immersion does), there's no such timing effect.
Pre-slice `_separately_timed_dhw` returned True for any Cat 4 HP
main BEFORE consulting WHC (line 3872 `if main.main_heating_category
== 4: return True`). For electric 2 (sap_main_heating_code=524 Cat 5
warm-air ASHP, main_heating_category=4 per Elmhurst mapper, WHC=903
electric immersion + cylinder + cylinder thermostat lodged), the
cat-4 branch fired before the existing `_is_electric_water` check
could route the cert to False. The cascade applied ×0.9 to the
Temperature Factor (53), pulling (55) from 1.2294 → 1.1064 → cascade
annual (56) = 403.87 vs worksheet (56) annual = 448.73.
Same WHC=903 principle as the prior slice S0380.156 (Table 3 zero-
loss list for electric immersion): when HW is independent of the
main heating, main-heating-specific DHW rules don't apply — even
when the main happens to be a HP / boiler / warm-air system.
Fix: new top-of-function `if epc.sap_heating.water_heating_code ==
_WHC_ELECTRIC_IMMERSION: return False` guard in
`_separately_timed_dhw`. Reuses the constant introduced in S0380.156.
Closures electric 2:
Cylinder (56) storage loss annual 403.87 → 448.73 (matches
worksheet 1.2294 × 365 = 448.73 EXACT within rounding)
HW kWh demand 2339.24 → 2384.12 (matches worksheet (62)/(64) =
2384.116 EXACT)
ΔSAP +0.8118 → +0.7002
Δcost −£18.71 → −£16.14
ΔCO2 −7.21 → −2.37 kg
ΔPE −161.68 → −108.58 kWh
The remaining +0.70 SAP residual is a separate upstream gap (likely
warm-air-HP SH cascade or Table 4a SH efficiency for code 524) —
follow-up slice.
No regressions on the other 24 cohort variants. Cohort-1 ASHP certs
(Cat 4 HP + WHC=901 = HW from HP + cylinder) keep ×0.9 as before
because their WHC=901 doesn't trigger the new guard. Extended
handover suite: 901 pass / 0 fail (was 900 — +1 from the new AAA
test). Pyright net-zero (43 → 43).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
SAP 10.2 Table 3 (PDF p.160) verbatim:
Primary loss is set to zero for the following:
Electric immersion heater
Combi boiler ...
CPSU ...
Boiler and thermal store within a single casing
Separate boiler and thermal store connected by no more than 1.5
m of insulated pipework
Direct-acting electric boiler
Heat pump (...) with hot water vessel integral to package
The Elmhurst WHC=903 lodging signals exactly the first row: "HW from
a separate electric immersion heater" — the cylinder is heated by an
immersion element inside the tank, no primary pipework between any
heat generator and the cylinder. The rule is universal: regardless
of what main heating exists for space heating, electric immersion
means no primary circuit means no primary loss.
Pre-slice `_primary_loss_applies` only consulted `water_heating_code`
in the Table 4a wet-boiler branch (codes 151-161 / 191-196). The Cat
4 HP branch returned True unconditionally when no PCDB record was
lodged; the Cat 1/2 boiler branch returned True unconditionally; the
PCDB Table 322 + Table 4b non-PCDB branches likewise. For the
electric 2 corpus variant (sap_main_heating_code=524 Cat 5 warm-air
ASHP, main_heating_category=4 per Elmhurst mapper, no PCDB record,
WHC=903 + cylinder), the Cat-4 branch falsely returned True and the
cascade added ~510 kWh/yr primary loss to a system with no primary
circuit at all.
Per-line walk discipline applied: cascade `water_heating_from_cert`
output dump showed `primary_loss_monthly_kwh_annual = 509.98` while
worksheet (59)m = 0 every month → spec lookup found Table 3 verbatim
"Electric immersion heater" zero-loss line.
Adds `_WHC_ELECTRIC_IMMERSION: Final[int] = 903` constant + a
top-of-function `if water_heating_code == _WHC_ELECTRIC_IMMERSION:
return False` guard that fires before any of the system-type-keyed
branches.
Closures electric 2:
HW kWh 2849.22 → 2339.24 (matches worksheet (62)/(64) = 2384.12
within the residual ~45 kWh storage-loss gap)
ΔSAP −0.4584 → +0.8118 (cascade swung past the worksheet by +1.27
— the pre-slice 'near-correct' value was offsetting cascade bugs
per [[feedback-software-no-special-handling]]; the +0.81 residual
exposes a separate upstream gap to chase in a follow-up slice)
Δcost +£10.56 → −£18.71
ΔCO2 +47.89 → −7.21 kg
ΔPE +443.13 → −161.68 kWh
No regressions on the other 24 cohort variants — only electric 2 has
the (Cat 4 HP, no PCDB, WHC=903) combination in the corpus.
Extended handover suite: 900 pass / 0 fail (was 899 — +1 from the
new AAA test). Pyright net-zero (43 → 43).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
5 certs in a 2026 API sample raised `KeyError: 'rr_common_wall_area_m2'`
and were blocked from computing. Root cause: `_part_geometry`'s early
return (taken when a building part lodges no sap_floor_dimensions —
e.g. a party-wall-only or RR-only extension as bp[0]) returned only 6 of
the 9 keys the full return exposes, omitting rr_common_wall_area_m2,
rr_gable_area_m2 and cantilever_floor_area_m2. The §3.9 RR contribution
block reads geom["rr_common_wall_area_m2"] / ["rr_gable_area_m2"] for
EVERY part, so the floorless part's truncated dict raised KeyError at
heat_transmission.py:974.
Fix: the early return now exposes all 9 keys, the three RR/cantilever
geometry values defaulting to 0.0 — correct, since a part with no floor
dimensions has no derivable RR shell or cantilever (no floor area).
Pure contract-completion bug; no spec/U-value change.
Regression test pins the invariant directly: a floorless part's
_part_geometry keys must equal a with-floors part's keys. Validated: all
5 certs now compute (4 within ~2 SAP of lodged; the 5th, 8536, has a
separate residual). §4 suite 2393 passed; heat_transmission.py pyright
unchanged at 12, test file at 71.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2b. Timber frame (wall_construction=5) takes internal wall insulation but
not external (not constructable — ADR-0019), so the generator offers IWI only.
Cascade pin: the IWI Option reproduces the re-lodged timber-frame after at
abs(diff) <= 1e-4 (general Table 6 insulation-thickness bucket, not the solid-
brick documentary path).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2a. New recommend_solid_wall emits one Main-wall Recommendation carrying
External + Internal wall-insulation Options for an uninsulated (wall_insulation
_type=4) solid-brick (wall_construction=3) main wall, each priced at the heat-
loss wall area. Cascade pin: the generator's EWI and IWI Options reproduce
their respective re-lodged afters at abs(diff) <= 1e-4.
Detection keys on wall_construction code, not description (ADR-0019 note
corrected): the Elmhurst ingestion path leaves walls[].description empty, so
the code is the only cross-path signal; codes 1-5 are consistent.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
above) → None
The 2026 sample lodges roof_construction=6 (1 cert, "Thatched, with
additional insulation") and =7 (6 certs, "(same dwelling above)" /
"(another dwelling above)"), both raising UnmappedApiCode and blocking
the cert. roof_construction_type is read ONLY for the §3 "sloping
ceiling" cos(30°) inclined-surface factor (Slice 89); the base roof
U-value comes from the global roofs[].description. Neither code is a
sloping ceiling:
- 6 = thatched — U set by the description, not this field;
- 7 = same/another dwelling above — an internal ceiling with no roof
heat loss (the roof-side analogue of floor_construction code 0,
governed by the roof_heat_loss / description path).
Map both to None: carries no information the cascade consumes here and
correctly avoids the cos(30°) false-trigger. Empirically inert and
validated — roof W/K is byte-identical whether 6/7 map to None or to an
explicit pitched string across all code-6/7 certs in the sample. 5 of
the 7 now compute (e.g. thatched cert 2276 SAP 62.8 vs lodged 63); the
other 2 also carry a gable_wall_type 2/3 raise (separate, worksheet-
backed slice).
Dict value type widened to Optional[str]. §4 suite 2392 passed; mapper.py
pyright unchanged at 32; new tests suppress reportPrivateUsage (net-zero).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Captures the grill-with-docs session for solid-wall insulation: CONTEXT.md
gains EWI/IWI Measure Types + the Wall Insulation Eligibility rule (+ a
flagged-ambiguity that the three planning flags stay distinct, never recollapsed
to legacy restricted_measures). ADR-0019 records the eligibility policy (cavity
-> cavity only; brick/system -> IWI+EWI; timber -> IWI only; cob/stone -> none;
conservation/flat block EWI, listed/heritage block both). ADR-0020 records
conservation/listed/heritage as three distinct Property attributes sourced by
extending the geospatial S3 repo (flags co-located with lat/long).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 1 of solid-wall insulation. BuildingPartOverlay gains a
wall_insulation_thickness field; the generic applicator already folds it onto
SapBuildingPart by name. With wall_insulation_type=1 (EWI) / 3 (IWI) + 100 mm,
the calculator derives the post-insulation U-value (§5.8 documentary path,
λ=0.04 default) — and for IWI also lowers the thermal-mass parameter. Two new
Elmhurst before/after cascade pins (solid-brick EWI + IWI, cert 001431)
reproduce the re-lodged after at abs(diff) <= 1e-4 across SAP/CO2/PE.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A 2026-register cert (4519-9056-4002-0222-4802) omits the top-level
post_town entirely (its town sits only in address_line_3 "BARNSTAPLE").
RdSapSchema21_0_x declares post_town as a required no-default field, so
from_dict raised "missing required field 'post_town'" and blocked the
whole cert from computing.
post_town is address metadata the SAP cascade never reads (no consumer
in domain/sap10_calculator/), so default an absent post_town to "" in a
from_api_response pre-processor (mirroring _normalize_shower_outlets) —
inert for the calculation, keeps the cert mappable. The schema dataclass
can't simply give post_town a default: it is a plain (non-kw_only)
dataclass with 57 required fields after post_town, so a mid-list default
would break field ordering.
Validated: cert 4519 now maps (post_town="") and computes SAP cont 74.68
vs lodged 75. §4 suite 2392 passed; mapper.py pyright unchanged at 32;
new tests suppress reportPrivateUsage (net-zero).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The 2026 sample's second-largest mapper raise: 37 certs lodge
sap_floor_dimensions.floor_construction=0, which raised UnmappedApiCode
and blocked the cert. Code 0 is the "not recorded / not applicable"
sentinel — 33/37 pair it with floor_heat_loss=6 ("another dwelling
below", an upper-floor flat with no ground floor to describe); the rest
carry mixed Solid / unheated-space descriptions. There is no single
construction to assert.
Map code 0 → None, which defers to RdSAP 10 Table 19 ("where floor
construction is unknown" → age-band default) — identical to how an
unlodged floor_construction (the 993 None certs) is already handled, and
honest about the absence (cf. the no-misleading-insulation_type rule).
Empirically inert and validated: across all 37 code-0 certs the cascade
floor W/K is byte-identical whether code 0 maps to None or to an explicit
"Solid" string — the another-dwelling-below floors compute to 0.0 W/K
(handled via floor_heat_loss + property_type=Flat + floors[].description,
per the _API_FLOOR_HEAT_LOSS_TO_FLOOR_TYPE code-6 note), and the few
genuine ground/unheated floors hit the same age-band default either way.
All 37 now compute (were raising).
Dict value type widened to Optional[str] for the None entry; helper
already returns Optional[str]. §4 suite + schema-mapper tests green
(pre-existing test_total_floor_area failure unrelated); mapper.py pyright
unchanged at 32; new test suppresses reportPrivateUsage (net-zero).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
