The gov-EPC API surfaces the assessor's RdSAP-assessed per-element U-values
as `roof_u_value` / `wall_u_value` / `floor_u_value` on each building part.
These were undeclared on the RdSAP 21.0.0/21.0.1 schemas, so `from_dict`
silently dropped them, and `heat_transmission` re-derived each U from the §5.6
/§5.7/§5.11 construction-default cascade. The gov OPEN data routinely redacts
the backing insulation thickness, so that re-derivation mis-bills an insulated
element as uninsulated.
RdSAP 10 §5.1: a known element U-value (documentary evidence / the lodged
RdSAP output) is used directly in place of the construction-default cascade.
Per [[project_per_cert_mapper_validation_state]] the gov API carries RdSAP
OUTPUT, so the lodged U reproduces the official's element heat loss exactly.
Worst case in the 2026 sample: cert 7921-0052-0940-5007-0663, an age-C
"Pitched, sloping ceiling" (rc=8) top-floor flat lodging roof_u_value=0.2 with
no thickness. The cascade returned the uninsulated 2.30 W/m²K → SAP 56.9 vs
lodged 80 (-23.09, the single largest error in the sample). The roof override
alone recovers ~15 SAP; the wall override (lodged 0.34 vs cascade) closes the
rest of this cohort.
Override applies to the MAIN wall only (alt-wall sub-areas keep their own
per-area U) and the part's floor=0. Fires only when the rare field is present
(9 of 909 computed certs), so the Summary path — which never lodges these
API fields — is untouched.
API gauge: 67.1% → 67.7% within-0.5, mean|err| 1.024 → 0.992.
Worksheet harness: 47/47, 0 divergers (unchanged).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Flat per-dwelling decommission price (sample_catalogue \£250) + 0.25 contingency
(covers unknown heater count / hard-wired-vs-plugged / repaint extent). The JSON
repo joins the contingency from config, proven by the new repo test. No composite
Products machinery — a lodged secondary is one roughly-fixed job, not room-scaled.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
recommend_secondary_heating_removal offers one standalone Option that clears the
lodged secondary system. Eligibility is purely physical (offer iff
sap_heating.secondary_heating_type is set) — no effectiveness gate, since a
lodged secondary is a fixed emitter per RdSAP (portables are ignored), and the
electric-storage §A.2.2 no-op is the Optimiser's call (ADR-0028 decisions 1-2).
Priced at a flat per-dwelling decommission cost, not room-scaled.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The first overlay surface that sets fields to *absent* rather than to a
target state: _fold_secondary_heating clears sap_heating.secondary_heating_type
+ secondary_fuel_type, so the calculator's Table 11 secondary-fraction split
(SAP 10.2 §9a) routes 100% of space heating to the main. On an electric-storage
main RdSAP §A.2.2 re-forces a default secondary, making removal a no-op there —
left to the Optimiser to de-select (ADR-0028 decisions 2-3).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The §5.16 Table 22 thermal-mass-parameter (TMP) "always low-mass" set was
{timber 5, cob 7, park home 8}. But wall_construction code 8 is OVERLOADED by
the same gov-API/calc code-space divergence as the wall-U fix: the Summary
path's "PH" mapping uses 8 for park home, while the gov-EPC API enum uses 8
for SYSTEM BUILD (Summary system build = code 6). So every API system-built
cert was mis-rated as low-mass 100 kJ/m²K instead of masonry 250 (Table 22
lists system build as masonry — PDF p.48, line "System build 250...").
A too-low TMP shortens the §7 time constant tau = Cm/(3.6·H), over-cutting
the temperature reduction so mean internal temperature is UNDER-stated →
space-heating demand under-stated → SAP over-rated. This was the cause of the
uninsulated system-built over-rate cluster (n=9 gas-boiler certs at signed
+2.39 vs cavity +0.43 / solid-brick +0.08 at the same bands — a system-built-
specific anomaly with a spec-correct wall U).
Fix: drop 8 from the always-low set and gate it on `property_type` — code 8 is
the low-mass park-home value only when the dwelling really is a park home,
otherwise it is gov-API system build and keeps masonry 250. Disambiguated by
the same `property_type == "park home"` signal used elsewhere in the cascade.
Worksheet harness UNAFFECTED (47/47, 0 divergers): the Summary path uses code
6 for system build and code 8 only for genuine park homes (which stay
low-mass via the property_type gate). API gauge 65.3% -> 67.1% within-0.5
(mean|err| 1.059 -> 1.024, signed +0.050 -> -0.002). The uninsulated
system-built cluster collapses +2.82 -> +0.28 signed (0/11 -> 7/11 within
0.5). 2 AAA tests (parametrised code-8 system-built -> 250; park-home
property -> 100). pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The gov-EPC API `wall_construction` enum diverges from the calculator's
internal WALL_* code-space (confirmed by the description-vs-code audit across
the corpus): API 1-5 align (granite/sandstone/solid-brick/cavity/timber), but
API 6=basement, 8=system built, 9=cob — whereas the calc constants are
WALL_SYSTEM_BUILT=6, WALL_COB=7, WALL_PARK_HOME=8, WALL_CURTAIN=9. Codes 8 and
9 therefore fell OUT of u_wall's `known_types` and resolved only via the
`walls[].description` fallback, with two failure modes:
- System built (API 8): a cert lodging no description silently defaulted to
cavity (1.5) instead of the system-built U (RdSAP 10 Table 6, e.g. band E
as-built 1.7). Latent in the corpus (all 43 carry a description) but a
silent mis-bill waiting to happen.
- Cob (API 9): a LIVE bug — calc WALL_CURTAIN=9 (set by the Summary path's
"CW" mapping, paired with a curtain_wall_age) intercepts code 9 in the
`construction == WALL_CURTAIN` branch, billing the cob wall at the curtain
default 2.0 regardless of description.
Fix, split by where each can be disambiguated safely:
- System built: `u_wall` gains `_GOV_API_WALL_CODE_TO_TYPE = {8: WALL_
SYSTEM_BUILT}`, resolving code 8 directly (calc WALL_PARK_HOME=8 is never
dispatched, so no collision; gov 6=basement is left to the basement
machinery — cannot remap 8→6).
- Cob: translated at the API mapper (`_api_wall_construction_code`, 9 →
WALL_COB=7) where the source is unambiguously the gov enum — the gov API
has no curtain code, so an API 9 is always cob. Applied to main + alt
walls across the from_rdsap_schema_* builders. The Summary path's "CW"→9
curtain mapping is untouched.
Worksheet harness UNAFFECTED (47/47, 0 divergers — Summary path unchanged).
API gauge 65.1% -> 65.3% within-0.5 (mean|err| 1.075 -> 1.059): the n=1 cob
cert now computes cob instead of curtain. 3 AAA tests (u_wall system-built
without description; mapper cob 9->7; aligned/system/basement pass-through).
pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_CYLINDER_SIZE_CODE_TO_LITRES` held only codes 2/3/4 (Normal/Medium/Large →
110/160/210 L); codes 5 (Inaccessible) and 6 (Exact) fell through to None,
so the Table-13 high-rate fraction AND the cylinder storage loss were skipped
for those certs (20 code-6 certs in the API sample).
Per RdSAP 10 Specification (10-06-2025) §10.5 Table 28 (PDF p.55):
- Code 6 "Exact": use the lodged measured volume. The gov API carries it in
`cylinder_size_measured` (e.g. 150 L) — now plumbed through the 21.0.0/21.0.1
schema → mapper → `SapHeating.cylinder_volume_measured_l`.
- Code 5 "Inaccessible": 210 L if off-peak electric dual immersion, 160 L from
a solid-fuel boiler, otherwise 110 L (n=0 in the current sample, but
spec-complete).
New `_cylinder_volume_l_from_code` centralises Table 28 resolution and replaces
the three raw-dict call sites (`_hot_water_cylinder_volume_l`, the cylinder
storage-loss path, and the PCDB performance check) so all three honour codes
5/6 identically. `_cylinder_inaccessible_volume_l` applies the code-5 context
rule via the existing immersion/off-peak-meter/solid-fuel-boiler detectors.
Worksheet harness UNAFFECTED (47/47, 0 divergers): the Summary path lodges
neither code 5/6 nor a measured volume. API gauge: within-0.5 64.4% -> 65.1%
(mean|err| 1.085 -> 1.075) — the 20 code-6 certs now size their cylinder from
the measured volume. 4 AAA tests (code 6 measured; code 5 solid-fuel/default/
off-peak-dual-immersion). pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The main-wall `u_wall(...)` call dropped the `dry_lined` kwarg, so the RdSAP 10
§5.7/§5.8 (PDF p.40-41) Table 14 dry-lining adjustment — U_adj = 1/(1/U₀ +
0.17) for a dry-lined (incl. lath-and-plaster) uninsulated wall — was never
applied to any main wall, even when the cert lodged `wall_dry_lined=Y`. The
ALTERNATIVE-wall path already passes `dry_lined` (line 1367); this one-sided
omission billed every dry-lined main wall at the un-adjusted (too-high) U →
wall heat loss too high → SAP under-rated.
Per-cert: a solid-brick (construction 3) band-A 230 mm main wall computes
U₀=1.70; dry-lined it is 1/(1/1.70+0.17)=1.32 — we were 22% too high. Across
the API gov-EPC sample the dry-lined `wall_construction=3` (solid brick)
sub-cohort sat at 10% within-0.5 / signed -1.33.
Fix: pass `dry_lined=bool(part.wall_dry_lined)` to the main-wall `u_wall`
call, mirroring the alt-wall path. `part.wall_dry_lined` is already plumbed
(Optional[bool], None → False). The three dry-lining branches in `u_wall`
(stone §5.6, solid-brick-by-thickness §5.7, generic uninsulated bucket §5.8)
are all spec-correct and already worksheet-validated (the bucket-0 cavity
case against cert 7700 age-C → 1.20).
Worksheet harness UNAFFECTED (47/47, 0 divergers): the Elmhurst/Summary
extractor only captures dry-lining for ALTERNATIVE walls (Summary §7), never
the main wall, so `part.wall_dry_lined` stays None on that path — this is a
pure API-path improvement. API gauge: within-0.5 60.1% -> 64.4% (mean|err|
1.163 -> 1.085, signed -0.097 -> +0.049). Both affected buckets improved
with no overshoot: solid brick (wc=3) 50% -> 57% within-0.5; cavity (wc=4,
dry-lined via the §5.8 bucket-0 path) 68% -> 72%.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A flat accessed via an unheated corridor/stairwell assumes a draught lobby
is present, so SAP 10.2 §2 line (13) = 0.0 rather than the 0.05 no-lobby
infiltration penalty. Per RdSAP 10 Specification (10-06-2025, p.30, "Draught
lobby"): "add infiltration 0.05 if draught lobby is not present, or use 0.0
if present. ... Flat or maisonette: Assume draught lobby if entrance door is
facing corridor (heated or unheated) or stairwell."
Signal: a SHELTERED alternative wall (the RdSAP §5.9 wall-to-unheated-corridor
surface) is the evidence that the flat's entrance faces a corridor — the same
evidence the corridor door (Table 26 U=1.4) rides on. New helper
`_has_sheltered_corridor_wall` factors that check out of `_corridor_door_count`
and gates `_has_draught_lobby`. Houses and exposed-gable flats (no sheltered
alt wall) keep the lodged value / "assume no lobby if cannot be determined"
default, so the §2 cascade is unchanged for every non-corridor dwelling.
The cascade previously added the 0.05 penalty unconditionally, over-counting
(16)/(18)/(21) by 0.05 ACH. On simulated case 34 (cert 001431 storage flat)
this lifted effective air change (25)m from the worksheet's monthly 0.572-0.638
to 0.574-0.668, over-counting space-heating demand (98) by +46.3 kWh/yr
(+0.41%) -> SAP -0.18. Closing it lands (25)m exactly on the worksheet (avg
0.6024) and (98) at 11356.3 vs ws 11357.2:
case 34 SAP 35.1325 -> 35.3130 vs ws 35.3094 (Δ -0.1769 -> +0.0036)
Guard-rails held (both improved): worksheet harness 47/47, 0 divergers (the
other corridor flat, cert 2474, -0.32 -> -0.02); API gauge 60.0% -> 60.1%
within 0.5, mean|err| 1.167 -> 1.163.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A door opening to an unheated corridor/stairwell takes U=1.4 W/m²K (RdSAP 10
Table 26, p.51 — any age band) instead of the 3.0 external-door default, and
its area deducts from the SHELTERED wall, not the main wall (RdSAP §3.7,
p.18: "the door of a flat/maisonette to an unheated stairwell or corridor
... is deducted from the sheltered wall area"). The cascade previously
billed every door at the external U on the main wall.
Signal: a SHELTERED alternative wall (`is_sheltered`, the RdSAP §5.9
wall-to-unheated-corridor surface, already modelled) is the evidence that
the dwelling is accessed via an unheated corridor, so one lodged door opens
to it. `_corridor_door_count` returns 1 when a sheltered alt wall is present
and >=1 door is lodged, else 0 — so the door channel is unchanged for every
non-corridor dwelling (houses, exposed-gable flats). `heat_transmission_
from_cert` gains a `corridor_door_count` param (default 0): it splits the
door area into external (main wall, age-default U) + corridor (sheltered
alt wall, U=1.4), threading the corridor door's area into that wall's
opening deduction and billing it at 1.4.
Validated on TWO faithful worksheets: simulated case 34 (cert 001431
storage flat — doors 8.14 exact, fabric 207.47 ≈ ws 207.48) and the
long-standing worksheet-harness diverger cert 2474 (−0.87 → −0.32, the
"space-demand thread" was the dropped corridor door). The worksheet harness
is now 47/47 with ZERO divergers.
API SAP gauge: 57.6% → 60.0% within 0.5; mean|err| 1.185 → 1.167; signed
−0.165 → −0.115 — ~22 sheltered-corridor flats were a systematic gap.
Regression gate green (3 pre-existing fails unrelated); pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Don't offer a like-for-like gas boiler swap to a dwelling whose existing gas
boiler is already at least as efficient as the new condensing boiler (SAP 10.2
Table 4b codes 102/104 = 84% winter) — it gains nothing, and the dwelling gets
the tune-up (cylinder + controls) instead. `_already_condensing` compares the
existing code's Table 4b winter efficiency to 84%; a non-Table-4b code (solid
fuel) has no comparable efficiency and is never treated as already-condensing.
The gate is GAS-ONLY: a non-gas boiler → gas is a fuel switch whose value (cost
/ carbon) is not captured by winter efficiency, so oil/LPG/coal → gas is never
suppressed on efficiency grounds (only gated on the mains-gas connection).
This correctly demotes the gas-with-cylinder example (cert lodges code 114
"Regular, condensing", 84% winter) to a tune-up case — confirming that 114→102
is ~0 boiler-efficiency gain in both our calc and Elmhurst (both Table 4b 84%);
Elmhurst's uplift there came from the cylinder + flue, not the boiler. The
boiler-with-cylinder overlay stays validated by the lpg pin (code 115, non-
condensing + cylinder) and by recasting the 114 fixtures' code to a pre-1998
non-condensing boiler (110) in the boiler tests — the overlay overwrites the
code to 102 regardless, so only eligibility changes, not the delta-0 result.
New tests: an already-condensing gas boiler yields no boiler upgrade (but a
tune-up); an oil condensing boiler is not gated (the fuel switch survives).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Table 12a (PDF p.191) is titled "High-rate fractions for systems
using 7-hour and 10-hour tariffs"; its "Immersion water heater" row lists
the tariff as "7-hour or 10-hour" only, routing to Table 13. An 18-hour or
24-hour tariff is OUTSIDE the table's scope — it provides at least 18
hours/day at the low rate, more than enough to heat any immersion cylinder
off-peak, so the high-rate fraction is 0 (all DHW billed at the low rate).
`electric_dhw_high_rate_fraction` previously mapped 18-/24-hour to the
10-hour equations (returning ~0.10 for a 110 L dual immersion) on an
over-literal reading of Table 13 Note 1 ("at least 10 hours"). The Elmhurst
dr87 worksheet for solid fuel 5 (cert 001431: 18-hour meter, 110 L dual
immersion, WHC 903) refutes that: HW (245) high-rate = 0.0 kWh, (246)
low-rate = 100%. Table 12a's title bounds the table to the two named
tariffs; 18-/24-hour fall outside it.
Resolves the Table-13 blocker on the immersion-extractor fix: once the
Summary extractor captures the dual immersion, the 18-hour solid-fuel
corpus certs stay at high_frac=0 (matching their worksheets) instead of
regressing to the 10-hour-column 0.10.
API SAP eval unchanged: 57.6% within 0.5, mean|err| 1.185, signed -0.165
(the cached sample has no 18-hour WHC-903 certs; one 24-hour cert shifts
sub-threshold). Regression gate green (3 pre-existing fails unrelated).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 §9.4.9 (PDF p.32) verbatim: "A cylinder thermostat should be
assumed to be present when the domestic hot water is obtained from a heat
network, an immersion heater, a thermal store, a combi boiler or a CPSU."
RdSAP 10 Table 29 (p.56) points the no-access default at this rule.
The storage-loss Table 2b temperature factor previously read only the
lodged `cylinder_thermostat` ("Y") — so an unlodged thermostat always took
the ×1.3 absent-penalty, over-stating storage loss by 30%. New
`_cylinder_thermostat_present` assumes it present when DHW is from a heat
network, WHC 903 (immersion), or a direct-acting electric boiler (SAP code
191 — electric-resistance, immersion-equivalent).
Found via the worksheet-folder harness: cert 2474-3059-4202-4496-3200
(Summary path: WHC 901, main SAP 191, electric, no lodged cylinder stat)
diverged −1.86 from its dr87 worksheet. The worksheet lodges (53)
temperature factor 0.6000 (present) and "add cylinder thermostat (SAP
increase too small)" — already assumed present. Fix lands HW output (64)
2701.99 → 2323.88, EXACT to the worksheet; 2474 −1.86 → −0.87 (residual is
a separate space-demand fabric thread). No other worksheet in the 47-cert
harness moved.
API eval within-0.5 56.9% → 57.6%; mean|err| 1.197 → 1.185; signed
−0.202 → −0.165. Regression green (only pre-existing fails); goldens +
heating corpus unaffected.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SAP 10.2 Table 3 (PDF p.160) verbatim: "For heat networks apply the
formula above with p = 1.0 and h = 3 for all months." The primary
circulation hours for a heat-network main are fixed at h=3 winter and
summer, independent of the cylinder-thermostat / separate-timing
lodgement that selects the h=5/h=11 rows for boiler systems.
`primary_loss_monthly_kwh` / `primary_circuit_hours_per_day_table_3` gain
a `heat_network` flag (→ (3, 3)); `_primary_loss_override` passes
`_is_heat_network_main(main)`. p=1.0 was already pinned via
`_HEAT_NETWORK_PIPEWORK_INSULATION_FRACTION`; only the hours were wrong.
Before, cert 8536 routed through the h=5/3 row because its community
biomass DHW fuel (31) collides with electricity code 31, so
`_separately_timed_dhw` returned False. The Table 3 heat-network rule
overrides that path: 8536 primary loss (59) 335.81 → 273.90, EXACT to
the faithful case-32 worksheet (storage (56) 376.58 also matches 376.94).
API eval within-0.5 57.0% → 56.9% (one offsetting-error cert crosses
out; signed err −0.205 → −0.202). Applied spec-uniformly per the
determinism principle — the heat-network primary hours are unambiguous.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A heat-network main with DHW from the network and no lodged cylinder was
billed the Table 3a keep-hot 600 kWh/yr combi loss (cat 6 sat in
`_TABLE_3A_COMBI_LOSS_MAIN_HEATING_CATEGORIES`). A heat network is not a
combi boiler — SAP 10.2 §4 line 7702 says combi loss is 0 for non-combi
systems.
SAP 10.2 p.24 "Heat networks" (c): when neither a PCDB Heat Interface
Unit nor a lodged cylinder applies, "a measured loss of 1.72 kWh/day
should be used, corrected using Table 2b. This is equivalent to a
cylinder of 110 litres and a factory insulation thickness of 50 mm".
RdSAP 10 Table 29 (p.56): a cylinder thermostat is assumed present when
DHW is from a heat network (Table 2b temperature factor 0.60).
New `_apply_heat_network_hiu_default_store` rebinds the 110 L / 50 mm-
factory store (thermostat present) onto a heat-network DHW cert with no
cylinder and no PCDB index, mirroring `_apply_rdsap_no_water_heating_
system_default`. The injected store routes storage loss (56) ≈ 376.7
kWh/yr (= 1.72 × 0.60 × 365) + primary loss (59) through the existing
machinery and zeroes the combi (61) loss via the has_hot_water_cylinder
gate. Verified against the user's faithful case-32 worksheet: storage
(56) 376.58 vs worksheet 376.94.
Cert 8536 storage 0→376.6, combi 600→0. API eval within-0.5 56.8% →
57.0%; signed err −0.218 → −0.205. Reworked
`test_heat_network_main_with_hw_from_main_dlf_scales_hot_water_kwh` to
assert the DLF scaling directly (fuel ÷ §4 output = 1.41) since the old
two-cert baseline premise (both combi-600) no longer holds.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Replace the flat placeholder scalars (boiler £3000; tune-up £500/£900) with a
per-dwelling composite cost, mirroring the ASHP architecture (ADR-0025): a
`HeatingRates` table (data, `heating_rates.json`), typed `BoilerCostInputs` /
`TuneUpCostInputs`, pure `Products.boiler_bundle_cost` / `tune_up_cost`, and
modelling-layer interpreters that read the dwelling into those inputs.
The cost mirrors the Simulation Overlay component-for-component, sharing the
controls + cylinder pricing across both options:
- tune-up (standard) = standard controls + cylinder fixes
- tune-up (zone) = zone controls + cylinder fixes
- boiler upgrade = £3200 all-in + standard controls (only when the upgrade
fired a controls change) + cylinder fixes
Standard controls are priced INCREMENTALLY — only the parts missing to reach
SAP 2106 (programmer £120 / room thermostat £150 / TRV £35×radiators), read
from a Table 4e Group-1 feature map so a dwelling that already has a room
thermostat + TRVs is only charged the programmer. Zone controls are a full
smart kit (hub £205 + smart TRV £50×radiators) — the smart TRV is itself the
room sensor, so there is no separate per-room sensor line. Cylinder fixes:
jacket £50 (when under-insulated) + thermostat £150 (when absent). The boiler
is a like-for-like wet swap (no radiators/flue/pipework — eligibility already
requires an existing wet boiler), so those dead-code extras are not modelled.
Figures are research-validated 2025/26 UK installed costs (legacy Costs.py
lineage); fully-loaded totals with one contingency on top (Model B, not the
legacy VAT/preliminaries engine). Contingency: boiler 0.26; tune-ups 0.10
(was a 0.15 placeholder). ADR-0027 records the design; CONTEXT.md's Heating
Eligibility entry updated to cover the partial boiler/tune-up family + composed
cost. Products cost pins (delta<=1e-9) + interpreter tests + generator
composite-cost assertions.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The GOV.UK API lodges a junk empty leading building part (all fields
None) ahead of the real Main Dwelling on some certs. Four sites in
cert_to_inputs.py read `sap_building_parts[0].construction_age_band` →
got None → silently dropped the dwelling age band. New `_dwelling_age_band`
helper takes the first part that lodges a band (a no-op for normal certs
where [0] is the Main part).
Closes two age-band-keyed defects on the 5 affected certs:
- SAP 10.2 Table 12c (p.193): the heat-network Distribution Loss Factor
defaulted to the K-or-newer 1.50 instead of the dwelling's true band
(cert 8536-0929-6500-0815-7206 is age A → 1.20), inflating distribution
loss by 30%.
- RdSAP 10 §4.1 Table 5 (p.28): the empty band ("") fell through the
age-band branches to the H–M habitable-rooms branch, defaulting in
phantom extract fans. The true band A correctly yields 0 fans
(bands A–E → 0).
Cert 8536: 31.76 → 41.12 vs lodged 39 (was −7.24, now +2.12). API eval
mean|err| 1.197 → 1.192, signed −0.229 → −0.218; headline within-0.5
holds at 56.8% (8536 lands at +2.1, a documented overshoot vs the
faithful case-31 worksheet — separate slice).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
An API audit flagged the solid-fuel room-heater space efficiencies
(_SPACE_EFF_BY_CODE 631-636) as reading the "Water" column of SAP 10.2
Table 4a. That was a misread: the two room-heater columns are (A)
minimum-for-HETAS-approved and (B) other appliances — BOTH are space
efficiency, not space/water. RdSAP defaults to column (B) when HETAS
approval is not lodged, which is what these values already hold and what
the reference software produces (Elmhurst worksheet "solid fuel 9", SAP
code 636 → (206) space efficiency = 70 = column B; flipping to column A
75 broke that pin and three sibling solid-fuel corpus pins).
No value change — add a pin test + spec-cited comment so the column-(A)/
(B) distinction is explicit and this misread can't recur.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add the system tune-up to the heating Recommendation: keep the existing wet
boiler but install better heating controls and fix the cylinder. Two competing
Options (the Optimiser picks <=1 across the whole heating rec) per the user's
two best control end-states:
- system_tune_up — standard controls (programmer + room thermostat +
TRVs, SAP 10.2 Table 4e code 2106)
- system_tune_up_zoned — time-and-temperature zone control (code 2110, type 3):
more SAP uplift for more cost
Both keep the boiler (no fuel / SAP code / flue change), set the control
ABSOLUTELY to their end-state, and apply the conditional cylinder fixes (an
80 mm jacket when under-insulated, a thermostat when absent — only when a
cylinder exists). Each control option is offered only when it genuinely improves
the existing control — standard is skipped when the control is already 2106 /
2110 / 2112, zone when already 2110 / 2112 — so neither is ever a downgrade or a
no-op.
Validated against the Elmhurst "system tune up" re-lodgements (cert 001431):
nine befores spanning controls 2101-2113 all converge to the two common afters,
proving the control overlay is absolute. The cascade pin is parametrised over
two starting controls (2101 "no control" + 2113 "room thermostat and TRVs") x
both afters, delta 0 (SAP/CO2/PE).
Wires the two MeasureTypes through contingencies (0.15), the offline catalogue
(500 / 900), the catalogue-coverage list, the report triggers, and the ARA
first-run seed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_separately_timed_dhw` returned True for any boiler+cylinder+from-main
cert, applying the SAP 10.2 Table 2b note b) ×0.9 temperature-factor
reduction unconditionally. For the lpg-boiler "before" worksheet (pre-
1998 LPG boiler SAP code 115 + 210 L cylinder, NO cylinder thermostat,
control 2113 "Room thermostat and TRVs" — no programmer) this dropped
the (53) temperature factor to 0.702 (= 0.60 × 1.3 × 0.9) where the
worksheet lodges 0.78 (= 0.60 × 1.3), under-counting cylinder storage
loss (55) by ~119 kWh/yr and over-rating SAP by ~0.25.
RdSAP 10 §10.5 (PDF p.57) "Hot water separately timed":
No programmer, pre-1998 boiler → No
Programmer, pre-1998 boiler → Yes
Post-1998 boiler → Yes
DHW is therefore NOT separately timed only when a pre-1998 boiler is
paired with a no-programmer control. Add the two SAP 10.2 Table 4c(2) /
Table 4b lookups (controls without a programmer = {2101, 2103, 2111,
2113}; pre-1998 gas/LPG boilers 110-119 + oil 124/125/128) and return
False for that combination; every other boiler+cylinder cert keeps the
separately-timed default, so the change is confined to old low-control
stock and the heating corpus + goldens are unchanged.
Effect: the full chain (Summary PDF → extractor → mapper → cert_to_inputs
→ calculator) now reproduces the lpg-boiler worksheet's §11a unrounded
SAP -6.6499 at abs < 1e-4 (was -6.4013). Full regression suite green bar
the 3 pre-existing unrelated fails.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Pin the coal-boiler-with-cylinder upgrade and add the `boiler_flue_type`
end-state field. A solid-fuel (coal) boiler (fuel 11, SAP code 153) on a
mains-gas street converts to a gas condensing boiler (fuel 11->26, code 102) —
the non-gas->gas path for a solid-fuel system, eligible because code 153 is in
the wet-boiler solid-fuel range 151-161 and mains gas is present.
New `boiler_flue_type` HeatingOverlay field, routed to main_heating_details[0]
and set to 2 (room-sealed/balanced) on both boiler shapes: every relodged after
lodges flue type 2, but coal's before lodged none. The field is SAP-inert (the
cascade score is unchanged by it), so it is written purely for end-state
fidelity — the overlay now represents the installed condensing boiler's flue.
Validated via the overlay-equality unit tests.
The coal after predates the user-locked "always add a cylinder thermostat when
absent" rule, so it stale-lodged thermostat 'N'; the pin corrects it to the
rule's end-state 'Y' in-test (the gas with-cylinder after got the same
correction by re-lodging). The cylinder is already 80 mm insulated, so the
jacket is skipped and only the thermostat is added; controls (2106) are
unchanged. Cascade-pinned delta 0 (SAP/CO2/PE).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Extend the gas-boiler-upgrade Option to combi (no-cylinder) dwellings and add
the controls upgrade shared by both boiler shapes. A dwelling has a cylinder or
it does not, so the one `gas_boiler_upgrade` Option is shaped per dwelling:
- no cylinder -> a gas condensing combi (Table 4b code 104), no cylinder fields
touched;
- a cylinder -> a regular boiler (code 102) heating it, with the conditional
cylinder jacket/thermostat (slice 1).
Controls: bring an inadequate boiler control up to full programmer + room
thermostat + TRVs (SAP 10.2 Table 4e Group 1 code 2106). "Inadequate" = the
Group-1 codes with NO room thermostat (2101, 2102, 2107, 2108, 2109, 2111) —
these lack boiler interlock (Table 4c(2) / footnote c) p.171), so adding a room
thermostat genuinely improves SAP. Room-thermostatted (2103/2104/2105/2106/2113)
or better zone controls (2110/2112) are left unchanged — never downgraded, so
no phantom uplift. The with-cylinder cert (control 2106) is therefore untouched
and its pin still holds at delta 0.
Validated by the combi before/after re-lodgement (cert 001431, gas boiler
upgrade - no cylinder): control 2111 "TRVs and bypass" -> 2106, fan flue
False->True, SAP code 112 -> 104. Cascade-pinned delta 0 (SAP/CO2/PE). Removed
the slice-1 placeholder test asserting no boiler Option fires without a cylinder
(the combi Option now correctly fires there).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add the first boiler-upgrade option to the single "Heating & Hot Water"
Recommendation (ADR-0024 expansion): a dwelling whose existing wet boiler heats
a hot-water cylinder is offered a new gas condensing boiler, with the cylinder
jacketed when under-insulated and given a thermostat when absent. One competing
Option (the Optimiser picks <=1), folded into one composite Plan line.
The end-state is read from the Elmhurst before/after re-lodgements (cert 001431,
gas boiler upgrade - with cylinder), which REVISE ADR-0024:
- Target is always a gas condensing boiler, not fuel-preserving: every after
lodges fuel 26. Gas->gas always; a non-gas wet boiler ->gas only with a
mains-gas connection; electric boilers are left alone (electrification is the
upgrade path). Eligibility = wet-boiler SAP code (Table 4a/4b 101-141 /
151-161 / 191-196) + not an electric boiler + mains gas present.
- End-state is a Table 4b SAP code, not a PCDB index: code 102 (regular boiler
+ cylinder). The calculator derives the condensing seasonal efficiency from
the code, so no efficiency input exists or is needed.
- A modern condensing boiler has a fanned flue: the after flips
`fan_flue_present` False->True on every cert (SAP 10.2 Table 4f flue-fan +
the Table 4b condensing-efficiency basis). Added as a new HeatingOverlay
field, routed to main_heating_details[0].
- Cylinder thermostat is always added when absent (user-locked); the jacket is
the 80 mm `cylinder_insulation_type=2` end-state, applied only when the
cylinder is below 80 mm (never downgrading a better one). Both are conditional
per-dwelling components, not a frozen overlay.
Cascade-pinned delta-0 (SAP/CO2/PE) against the relodged after via
`_assert_overlay_reproduces_after`. NB the absolute SAP on this dwelling is
subject to a separate Summary-path mapper roof-fidelity gap (we read the roof
better-insulated than Elmhurst, scoring ~75 vs the printed 56); the gap is
identical on before+after (the boiler measure never touches the roof) so it
cancels and the pin still proves the exact heating field-delta. Tracked on the
calculator branch.
Wires the new `gas_boiler_upgrade` MeasureType through contingencies (0.26),
the offline sample catalogue, the catalogue-coverage list, and the ARA
first-run integration seed (the option fires on any mains-gas boiler+cylinder
dwelling).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The heat-network HW distribution-loss override fired only when the MAIN was
a heat network AND whc inherited from main ({901,902,914}). Water-heating-only
heat networks (SAP 10.2 Table 4a HW codes 950 boilers / 951 CHP / 952 heat
pump) were missed entirely: their Table 4a plant efficiency applied with NO
distribution loss, so the HW fuel was under-counted by the Table 12c DLF
(1.33-1.48x) → under-cost → over-rate.
RdSAP 10 §10 (spec p.36): a water-heating-only heat network is calculated 'for
plant efficiency, distribution loss and pumping energy - see Table 12c'. Added
a whc-gated branch (independent of the main) applying water_eff = plant_eff /
DLF — the per-kWh-generated cost model (q_generated = q_useful x DLF). Fires on
the WHC alone so a HW-only heat network with a non-network main (cert 9093, whc
950 + warm-air main 502) is covered.
The 3 corpus whc=950 certs all improve in |err|: 2153 +2.62->-0.48 (now within
0.5), 7220 +1.27->-0.97, 9093 +6.04->+3.60 (residual is its warm-air main, a
separate cause). within-0.5 56.66->56.79%, within-1.0 71.9->72.2%, mean|err|
down; only those 3 certs change. New AAA test pins the DLF scaling fires on the
WHC independent of the main. Goldens + gate green, pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Forcing-function guards so a lodged-but-unmapped code surfaces loudly instead
of silently taking a wrong-but-plausible default (the class that hid single
glazing as U=2.5 until this session). Four silent fallbacks converted to raise
on PRESENT-but-unmapped codes, while keeping the legitimate ABSENT (None)
defaults:
- _api_glazing_transmission: unmapped glazing_type -> UnmappedApiCode (was
None -> u_window all-None default 2.5).
- _api_cascade_glazing_type: unmapped glazing_type -> UnmappedApiCode (was
pass-through -> wrong g-value slot).
- seasonal_efficiency: a lodged code/category resolving in neither
_SPACE_EFF_BY_CODE nor the category/room-heater fallbacks -> UnmappedSapCode
(was blind 0.80 gas-boiler default, which 'catastrophically misrates heat
pumps and storage' per the table comment). Data-free calls keep 0.80.
- water_heating_efficiency: WHC in no SAP 10.2 Table 4a HW row ->
UnmappedSapCode (was blind 0.78). Absent code keeps 0.78.
Zero current-corpus impact (909 computed / 0 raises, 56.66% within-0.5
unchanged) — the code/efficiency tables are complete for today's data, so
these are guards for the ongoing audit + future data refreshes. Verified the
WHC table already covers 908 (multi-point gas) and 950 (HW heat network), so
those are NOT unmapped-code bugs. 8 AAA tests, goldens + gate green, pyright
net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Tier-1 finding of the silent-fallback audit. The fuel-type helpers fed the
SAP 10.2 Table 12/32 cost/CO2/PE lookups via a silent
`API_FUEL_TO_TABLE_12.get(fuel, fuel)` passthrough at 5 sites
(_heat_network_factor_fuel_code, HW CO2/PE, _secondary_fuel_code, PV). A fuel
code in NEITHER the API enum map NOR the Table-12 numbering passed straight
through to the mains-gas default baked into unit_price_p_per_kwh /
co2_factor_kg_per_kwh / primary_energy_factor (table_12.py:233/274/287,
table_32.py:190) — silently mis-pricing a novel/colliding fuel as grid gas.
This is the class that mis-priced cert 8536's community biomass as
electricity (-17 SAP) before a7761ea8.
New _table_12_factor_fuel_code mirrors .get(fuel, fuel) EXACTLY for every
recognised input (union of the CO2/PE/price/monthly table keys +
API_FUEL_TO_TABLE_12 values) and raises UnmappedSapCode only when the
resolved code is recognised by no table — surfacing the gap loudly per the
strict-raise principle (reference_unmapped_sap_code). Verified behaviour-
preserving: 0/909 corpus certs hit the new raise; eval unchanged at 54.9%
within-0.5 / 909 computed / 0 raises.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Completes the MEV fan-electricity thread. The PCDB-index slice closed the
9 MEV certs carrying a Table 322 record; the other 11 (mostly gas houses)
lodge mechanical_ventilation=2 with NO PCDB index, so
`_mev_decentralised_kwh_per_yr_from_cert` returned 0 and billed no fan
running cost — a tight +2.2 SAP over-rate (signed +1.23, median +2.19).
SAP 10.2 §2.6.3 / Table 4g note 1 (PDF p.176) prescribes a DEFAULT
specific fan power of 0.8 W/(l/s) for an MEV system whose fans are not in
the PCDB, used directly as SFPav in the §5 Table 4f (230a) formula
(SFPav × 1.22 × V). Restructure the helper: when no Table 322 record
resolves, fall back to the default for a mechanical-extract system
(`mechanical_ventilation_kind == EXTRACT_OR_PIV_OUTSIDE`); natural /
balanced (MVHR / MV) systems still contribute nothing.
Index-less extract cohort closed +1.23 -> +0.18 signed (each gains
~1.1 SAP of fan electricity). This is a spec-correct fix that improves
the aggregate but is a HEADLINE TRADE-OFF: within-2.0 83.6% -> 84.6%,
within-1.0 70.08% -> 70.19%, mean|err| 1.232 -> 1.224, but within-0.5
55.12% -> 54.90% (-2) — the fan energy is only ~half each cert's
over-rate, so the cohort lands at ~+1.0 (still outside 0.5) while two
borderline certs with offsetting errors cross out. Applied uniformly per
the determinism principle ([[feedback_software_no_special_handling]]):
the unmasked residual (~+1.0 on gas-house MEV) is the next lead.
1 AAA test (default SFP 0.8 × 1.22 × V for index-less MEV, 0 for
natural). Goldens + full calc/epc regression green (000565 MEV uses its
resolvable PCDB record, unaffected); pyright net-zero.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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>
The gov-API `main_fuel_type`/`water_heating_fuel` enum (epc_codes.csv)
codes 30="waste combustion (community)", 31="biomass (community)",
32="biogas (community)" collide in VALUE with the Table-32 electricity
codes 30 (standard rate), 31 (7-hour low) and 32 (7-hour high). All three
sit in `_ELECTRIC_FUEL_CODES`, so `is_electric_fuel_code` flagged a
community-scheme main as electric and `_is_electric_main` routed its cost
through the off-peak electricity branch — BYPASSING the heat-network rate
in `_heat_network_factor_fuel_code`. Cert 8536 (biomass community, SAP
code 301) was billing at 5.5 p/kWh grid electricity instead of the 4.24
p/kWh heat-network rate → -17.2 SAP.
Per RdSAP 10 §C / SAP 10.2 Table 12 (PDF p.191) the community
waste/biomass/biogas rows are codes 42/43/44 (the same rows the
backwards-compat enum codes 11/12/13 already map to). Add 30->42, 31->43,
32->44 to both API fuel-translation tables.
The remap CANNOT be global (`canonical_fuel_code`): the cascade uses the
bare Table-32 code 30 internally as `_STANDARD_ELECTRICITY_FUEL_CODE`
(the RdSAP no-water-heating immersion default writes
`water_heating_fuel=30`), so a blanket remap mis-prices genuine grid
electricity as community waste (cert 2211 regressed +16 SAP in a
prototype). Instead `_heat_network_community_fuel_code` translates only
when `_is_heat_network_main` is true, at the `_main_fuel_code` /
`_water_heating_fuel_code` fuel-TYPE boundary, where the community
meaning is unambiguous.
Per the strict-raise principle ([[reference-unmapped-sap-code]]), a
heat-network main lodging a colliding community fuel the table doesn't
cover raises `UnmappedSapCode` rather than silently falling through to
the same-numbered electricity code.
Eval (API SAP vs lodged): cert 8536 -17.25 -> -6.51, cert 5036 -6.29 ->
+1.36; mean|err| 1.329 -> 1.312, within-1.0 67.88% -> 67.99%,
within-2.0 81.74% -> 81.85%, within-0.5 held at 53.14%, 909 computed /
0 raises. No golden / calculator regressions.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add domain/modelling/considered_measures.py::restrict_to_considered_measures —
the pure allowlist that limits a run to a chosen set of MeasureType (mirroring
the legacy engine's `inclusions`). It filters at the Option level, so a
multi-option Recommendation (e.g. Heating & Hot Water competing HHRSH against
an ASHP bundle) is kept with only its allowed Options; a Recommendation left
with none is dropped. None = consider everything (unrestricted default).
Thread `considered_measures: frozenset[MeasureType] | None` through
ModellingOrchestrator.run -> _plan_for -> _scored_candidate_groups /
_candidate_recommendations (applies the filter) and _measure_dependencies
(suppresses a forced dependency whose required measure is outside the
allowlist, so a restricted run forces nothing it is not considering). The
local-run seam (harness.console.run_modelling) gains the same param.
The Optimiser still freely chooses among survivors — including none. Tests:
the pure filter (3 cases) + an orchestrator-seam test proving a
{solar_pv}-restricted run yields only solar_pv options. 257 pass + 3 xfail;
pyright clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A coal main (gov-API main_fuel_type=33) was priced at the electricity
10-hour low rate (7.5 p) and anthracite (5) at the bulk-LPG rate
(12.19 p), because the shared price/CO2/PE lookups check Table-32/12-code
membership BEFORE translating the API enum — and codes 5/33 collide with
a different-fuel Table code. This drove the cohort's single worst cert
(2100 anthracite, -61 SAP). `is_electric_fuel_code(33)` also wrongly
classified the coal main as electric.
The gov-API fuel enum (confirmed by description-vs-code audit on
main_heating[].description): 5=anthracite, 33=coal, 9=dual-fuel,
20/25/31=community. The collision can't be resolved inside the shared
table functions — code 33 is ALSO the electricity-10h TARIFF code used by
the dual-rate CO2/PE split (golden 000565), so normalising there breaks
electricity certs. Instead `canonical_fuel_code` normalises the colliding
SOLID-fuel enums (5->15 anthracite, 33->11 house coal) at the fuel-TYPE
boundary in `_main_fuel_code` / `_water_heating_fuel_code`, where the code
is known to be a fuel type (never a tariff code).
Scoped to anthracite (5) + coal (33) — the unambiguous large mispricings.
Dual-fuel (9, 0.45 p delta) and community (20/25/31, heat-network path)
are deferred (noted in `_GOV_API_COLLISION_FUELS`).
API SAP eval: mean|err| 1.424 -> 1.329 (the -61 anthracite outlier 2100
-> -11, residual now fabric); within-0.5 53.1% (flat); 909 computed, 0
raises. Golden + Elmhurst regression green (the shared table functions
are unchanged, so the electricity-tariff CO2/PE path is untouched).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Tighten the recommendation/plan vocabulary off generic str:
MeasureOption.measure_type and PlanMeasure.measure_type are now MeasureType
(also _GlazingTarget.measure_type, MeasureDependency.triggers ->
frozenset[MeasureType], and the optimiser's chosen/required-type locals).
Because MeasureType is a StrEnum the change is transparent to persistence
(the `recommendation` varchar column), the optimiser group-by key, and every
`== "solar_pv"`-style comparison — so pyright now enforces the enum at every
construction site with no runtime behaviour change.
The catalogue boundary stays str: ProductRepository.get(measure_type: str)
and Product.measure_type are unchanged (they map arbitrary DB/JSON rows), so
the fake product repos in tests need no edit. Test construction helpers coerce
their str arg via MeasureType(...); direct constructions use members.
Suite green: tests/domain/modelling + orchestration + harness 253 pass + 3
xfail; pyright clean on production + tests (pre-existing moto + property-
override-rowcount baselines untouched).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Introduce domain/modelling/measure_type.py — a StrEnum with one member per
modelled measure (the 15 the generators emit). A StrEnum so each member *is*
its string value: it persists straight into the `recommendation` varchar
column, is the optimiser's group-by key, and compares equal to the catalogue /
EPC strings — so it replaces the per-generator string constants with no
persistence or optimiser change.
Repoint every generator's measure-type constant/literal to a MeasureType
member (wall, solid_wall, roof, floor, glazing, lighting, ventilation,
heating, solar). Field annotations stay `str` for now; tightening them to
MeasureType is the next slice.
This is the enum the historical engine deferred (engine.py:970
"TODO - formalise property measure types into an enum") and the vocabulary the
forthcoming `considered_measures` allowlist will speak (mirroring the legacy
`inclusions`).
Suite green: tests/domain/modelling + orchestration + harness 253 pass + 3
xfail; pyright clean on the enum + generators.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A flat roof lodged "Flat, no insulation" / "Flat, limited insulation" with
an undetermined insulation thickness ('ND'/'AB' → parsed None) was given the
Table 16 row-0/12mm U (2.30 / 1.50) from the description marker, regardless
of age band. Per RdSAP 10 §5.11.4 (PDF p.44) "U-values in Table 18 are used
when thickness of insulation cannot be determined" — the column (3)
flat-roof age-band default applies. The "no/limited insulation" text is
RdSAP's as-built rendering: at old bands (A-D) the column (3) default IS
2.30 (so those certs are unchanged), but a newer-band flat roof carries the
age-band insulation as built (band H = 0.35, F = 0.68, not 2.30).
Confirmed by the description-vs-rating audit: cert 0390-2753 (top-floor
flat, band H, "Flat, no insulation", thickness 'ND') lodges roof
energy_efficiency_rating = 3 (moderate U), NOT the rating-1 that 2.30
implies — and drove a -31.78 SAP error (roof 202 W/K over 88 m²). Same
masked-at-old-bands structure as the cavity-U fix: accurate at A-D where the
default coincides with 2.30, catastrophic only where it diverges.
Pitched roofs are deliberately NOT rerouted (their "no insulation" text is
load-bearing — the broad 'ND'→Table-18 reroute was empirically net-negative
for pitched lofts).
API SAP eval: 52.1% -> 53.1% within 0.5; <1.0 67.2% -> 68.0%; median |err|
0.475 -> 0.467; mean|err| 1.497 -> 1.424; flat-roof bucket within-0.5
23% -> 35% (11 improved, 2 regressed).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
An as-built cavity wall (wall_insulation_type=4) lodged "Cavity wall, as
built, insulated (assumed)" was routed to RdSAP 10 Table 6's "Filled
cavity" row. Per Table 6 (England, PDF p.41) the Filled-cavity row carries
the "†" footnote ("assumed as built") only at age bands I-M, where it is
numerically identical to "Cavity as built"; at bands A-H the Filled-cavity
row represents a GENUINE fill, not the as-built assumption. So an as-built
cavity must use the "Cavity as built" row at all bands (band G/H = 0.60,
not the filled 0.35).
This is the same latent A-H bug slice S0380.210 fixed for the "partial
insulation (assumed)" variant but left in place for "insulated (assumed)"
by a legacy production convention. The API SAP-accuracy cohort over-rated
"Cavity wall, as built, insulated (assumed)" certs at bands G/H by a clean
+1.38 / +1.61 SAP median (n=37 / n=18); bands I-M were unaffected (rows
coincide), confirming the spec mechanism per-band.
Retires the `_cavity_described_as_filled` description sniffer — as-built
cavities now always use the as-built row regardless of the rendered
insulation adjective; a genuine retrofit fill is still caught by the
explicit wall_insulation_type=2 branch.
API SAP eval: 48.6% -> 52.1% within 0.5; <1.0 63.8% -> 67.2%; median |err|
0.548 -> 0.475; mean|err| 1.561 -> 1.497; 909 computed, 0 raises.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Electric immersion water heating (WHC 903) on an off-peak tariff billed
100% at the low rate, under-costing the dwelling and over-rating it
(median +0.98 SAP across the off-peak WHC-903 API cohort, n=57).
SAP 10.2 Table 12a "Immersion water heater" row (PDF p.191) routes the
water-heating column to Table 13 (PDF p.197): the high-rate fraction is
a function of cylinder volume V, assumed occupancy N (Appendix J Table
1b) and single-/dual-immersion. The remainder bills at the low rate.
Table 13 Note 2 supplies exact equations equivalent to the rounded grid;
`electric_dhw_high_rate_fraction` evaluates them (validated against the
published 110 L grid cells). Per Note 1 the 10-hour equations cover any
tariff with >=10 hours/day low-rate (so 18-/24-hour use that column).
Immersion code mapping CONFIRMED 1=dual, 2=single via RdSAP 10 §10.5
(PDF p.54 — an immersion is "assumed dual" on a dual/off-peak meter)
cross-checked against the API cohort (code 1 sits 3.6:1 on dual meters;
code 2 on single meters). This INVERTS an earlier handover's unverified
"1=single, 2=dual" note — the dual code carries Table 13's small
fraction, matching the cohort over-rating direction; the single mapping
overshot in a prototype.
API SAP eval: 47.6% -> 48.6% within 0.5; <1.0 62.6% -> 63.8%;
mean|err| 1.586 -> 1.561; 909 computed, 0 raises.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_secondary_fraction` keyed "has a secondary" off the integer
`secondary_heating_type` code. The gov-API path surfaces the secondary as a
DESCRIPTION instead (`secondary_heating.description`, e.g. "Portable electric
heaters (assumed)") and leaves the integer code None. So a gas/oil boiler
main (not in the §A.2.2 forced-secondary set) with an assumed portable-electric
secondary dropped the secondary entirely (sec_kWh=0), under-costing the
dwelling and over-rating its SAP.
Per RdSAP §A.2.2 / SAP 10.2 Table 11, a lodged secondary is costed at its
Table 11 fraction (cat-2 boiler = 0.10, billed at standard-rate electricity per
the §A.2.2 assumed portable-electric default). New
`_has_lodged_secondary_description` treats a real `secondary_heating.description`
as a lodged secondary; passed to `_secondary_fraction` at both call sites. The
description is authoritative — same lesson as floor_heat_loss / roof codes.
(Electric-storage mains were unaffected: they force the secondary already.)
Also adds the Table 11 fraction for main_heating_category=8 (electric underfloor,
"Integrated storage/direct-acting electric systems" = 0.10) — the strict-raise
surfaced this latent gap once cat-8 mains were routed through the lookup.
Eval: 909 computed, 0 raises, 46.9% -> 47.6% within 0.5 (+13 certs: 420 -> 433),
mean|err| 1.633 -> 1.586. 13 improved / 1 regressed (2610, a cat-10 room-heater
cert with an independent over-count). Bucket "Portable electric heaters"
median +2.73 -> ~0 on the gas/cat-2 subset (cat-7 storage was already correct).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
`_BOILER_NO_ROOM_THERMOSTAT_CONTROL_CODES` held only {2101, 2102} — it was
keyed off the Table 4e "+0.6 °C" annotation rather than the actual interlock
criterion. SAP 10.2 §9.4.11 (PDF p.66): "A boiler system with no room
thermostat (or a device equivalent in this context, such as a flow switch or
boiler energy manager) ... must be considered as having no interlock", and
"TRVs alone ... do not perform the boiler interlock function". A fixed bypass
likewise provides no interlock (it keeps water circulating when TRVs close).
So control 2107 ("Programmer, TRVs and bypass") and 2111 ("TRVs and bypass")
lack interlock and must take the Table 4c(2) −5pp Space+DHW seasonal-efficiency
adjustment and the Table 4f footnote a) ×1.3 circulation-pump uplift — both of
which they previously missed. (2108 flow switch / 2109 boiler energy manager
carry interlock-equivalent devices → excluded; 2103-2106/2113 have a room
thermostat.) All affected certs are cat-2 gas boilers, where §9.4.11 applies.
Eval: 909 computed, 45.3% → 46.9% within 0.5 (+14 certs: 412 → 426), mean|err|
1.659 → 1.633. Bucket means corrected: control 2107 +1.50 → +0.32 (n=38),
2111 +1.48 → +0.16 (n=4). 32 improved / 10 regressed (all small; the six that
crossed out of ±0.5 were coincidentally-accurate offsetting-error certs).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Pulls in 42 commits of calculator/mapper accuracy fixes from the per-cert
mapper-validation and floor/roof/heating fronts.
Conflict resolutions:
- mapper `_is_elmhurst_roof_window`: main dropped the branch's "wall location →
vertical" guard (it broke cert 000516's rooflight), but that re-broke cert
001431's two External-wall U>3.0 windows (which must stay vertical). The two
certs lodge a BYTE-IDENTICAL §11 row, so neither location nor U separates
them — the real discriminator is the room-in-roof context. Replaced the
unconditional U>3.0 backstop with one gated on the BP having a room-in-roof
(`_elmhurst_bp_has_room_in_roof`): 000516's Main BP has a "Room in roof type
1" (→ rooflight), 001431's does not (→ vertical). Validated against BOTH —
full Elmhurst worksheet suite 1038 pass + the 001431 window-extraction pin.
- property_postgres_repository: kept main's `ids_by_uprn` method + the branch's
`_restrictions_of` helper.
- sap_fuel.py: the branch relocated it to domain/billing/ (already carrying
main's to_table_32_code normalization), so kept the old path deleted.
Fallout from main's fabric fixes (validated by the boiler-3 real-cert pin which
still reproduces at delta 0):
- re-pinned the boiler-1 + boiler-instant-hw ASHP snapshot scores;
- main's §14.2 gas-boiler main-fuel derivation resolved the BGB/102 baseline
gap, so `test_gas_boiler_instant_hw_before_baselines` is now a passing test
(was an xfail tripwire).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 6 of the Solar PV Recommendation Generator (ADR-0026). `recommend_solar`
emits one "Solar PV" Recommendation of up to five conservatively-sized configs
× {no battery, battery} = ≤10 competing Options (a free Optimiser candidate).
Each Option folds a SolarOverlay built from the chosen config: one
PhotovoltaicArray per non-north segment (peak_power = panels × panelCapacityW /
1000; orientation/pitch from geometry; generation-calibrated overshading),
is_dwelling_export_capable set True absolutely, a diverter when the dwelling
has a cylinder (None for a combi), a 5 kWh battery for the battery variant, and
the per-config composite cost from Products.solar_bundle_cost.
Eligibility = house/bungalow ∧ not listed/heritage (blocks_internal, the same
gate as ASHP — a conservation area does NOT block PV) ∧ no existing PV ∧ a
feasible SolarPotential. Flats and existing-PV top-up are deferred.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 7 of the Solar PV Recommendation Generator (ADR-0026). Adds the
composite per-dwelling Solar PV cost on the Products collection (ADR-0025
pattern): pv_system(kWp band, nearest of the ECOPV06-13 EA bands 1.0→4.5 kWp,
floor/cap at the ends) + scaffolding(£900 first elevation + £450 each
additional, default 2) + enabling base (EICR £150 + DNO £50 + 2-way consumer
unit £330) + [diverter £980 if cylinder] + [battery if the with-battery
variant] → Cost(total, contingency_rate 0.15).
Rates are data in the committed solar_rates.json (Southern Housing "SOLAR PV &
BATTERY" EA column), loaded via SolarRates.from_json/.default and injectable.
The £2,000 / 5 kWh battery is NOT on the rate sheet — a flagged estimate
(battery_estimate=true), confirmed with the user to stand in until a DB rate.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
