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>
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>
Slice 10 of ADR-0025 costing. The Southern Housing rate table moves from code
constants into ashp_rates.json (structured rows the flat scalar catalogue can't
hold), loaded via AshpRates.from_json. Products takes an injected AshpRates
(default: the committed sheet), so rates are now data -- tunable (e.g.
reuse_distribution_fraction) without a code change, and ready for ETL/DB-supplied
rates later. Behaviour-preserving: the 6 pinned cost tests still hold against the
default, plus a new test proving injected rates drive the total.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 4 of ADR-0025 costing. ASHP is offered to any house regardless of fuel,
so _decommission now prices a fallback instead of raising: no system -> 0,
electric room/panel heaters -> electric-storage line, anything else -> gas
line (representative default). Never blocks ASHP eligibility.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 3 of ADR-0025 costing. When the dwelling has a reusable wet system,
_distribution charges a power-flush (168) plus _REUSE_DISTRIBUTION_FRACTION
(0.5) of the full radiator band -- a documented stand-in for partial radiator
upsizing at ASHP flow temps, the headline uncertainty in the model. Without a
wet system the full new distribution is priced.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2 of ADR-0025 costing. _decommission maps the existing system to its
Southern Housing line: gas/oil flat 720, LPG 960 (tank+fuel removal),
electric-storage 570/840 by property-size band. Unmapped systems raise for
now -- the no-system/electric-other/other fallbacks land in the next slice.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
First slice of the per-dwelling ASHP bundle costing (ADR-0025). Products is
the rich catalogue collection over Product, owning the catalogue math: given
a typed AshpCostInputs it sums the applicable Southern Housing rate lines
(decommission + heat-pump band + fixed cylinder + full wet distribution) into
a Cost with the separate 25% ASHP contingency. Pure -- no EpcPropertyData or
calculator. Pinned exact (1e-9) against the real rate sheet. Reuse branch,
decommission variants, fallbacks, band edges and radiator clamp follow.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
