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Model/domain/modelling/generators/heating_recommendation.py
Daniel Roth 266a276dae revert changes
2026-07-01 09:52:06 +00:00

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"""The heating Recommendation Generator.
Detects a dwelling whose heating system should be replaced and emits one
"Heating & Hot Water" Recommendation of competing whole-system bundles — the
Optimiser picks at most one (ADR-0024). Each bundle is a whole-system change:
main heating + controls + fuel + meter + the implied hot water, folded into one
Measure Option's `HeatingOverlay`. Hot water is never a separate competing
measure; the legacy heating-vs-HW split double-counted.
This slice covers the high-heat-retention storage (HHRSH) bundle; the ASHP and
boiler bundles land in later slices. Detection + pricing only — impact is
produced by scoring (ADR-0016).
"""
from typing import Optional
from datatypes.epc.domain.epc_property_data import EpcPropertyData, MainHeatingDetail
from datatypes.epc.domain.field_mappings import PROPERTY_TYPE_LOOKUP
from domain.geospatial.planning_restrictions import PlanningRestrictions
from domain.modelling.products import (
AshpCostInputs,
AshpExistingSystem,
BoilerCostInputs,
Products,
TuneUpCostInputs,
)
from domain.modelling.measure_type import MeasureType
from domain.modelling.product import Product
from domain.modelling.recommendation import Cost, MeasureOption, Recommendation
from domain.modelling.simulation import EpcSimulation, HeatingOverlay
from domain.sap10_calculator.tables.table_4b import (
table_4b_seasonal_efficiencies_pct,
)
from repositories.product.product_repository import ProductRepository
_HEATING_SURFACE = "Heating & Hot Water"
_HHR_STORAGE_MEASURE_TYPE = MeasureType.HIGH_HEAT_RETENTION_STORAGE_HEATERS
_ASHP_MEASURE_TYPE = MeasureType.AIR_SOURCE_HEAT_PUMP
_GAS_BOILER_UPGRADE_MEASURE_TYPE = MeasureType.GAS_BOILER_UPGRADE
_SYSTEM_TUNE_UP_MEASURE_TYPE = MeasureType.SYSTEM_TUNE_UP
_SYSTEM_TUNE_UP_ZONED_MEASURE_TYPE = MeasureType.SYSTEM_TUNE_UP_ZONED
# Electricity main-fuel code (Elmhurst → SAP10 Table 12).
_ELECTRICITY_FUEL = 30
# Table 4a SAP main-heating code for high-heat-retention storage heaters; an
# existing HHR system lodges this already, so it is not re-recommended.
_HHR_STORAGE_SAP_CODE = 409
# RdSAP main_heating_category for a heat pump (Table 4a) — an existing heat pump
# is never downgraded to storage heaters.
_HEAT_PUMP_CATEGORY = 4
# The HHRSH bundle's absolute end-state (ADR-0024): high-heat-retention storage
# heaters (Table 4a code 409) on a dual off-peak meter, with an off-peak
# electric immersion hot-water cylinder. Pinned against the relodged after-cert
# in the cascade tests; `mains_gas` and the heat emitter are unchanged by this
# measure, so they are not written.
_HHR_STORAGE_OVERLAY = HeatingOverlay(
main_fuel_type=_ELECTRICITY_FUEL,
sap_main_heating_code=_HHR_STORAGE_SAP_CODE,
main_heating_control=2404,
water_heating_code=903,
water_heating_fuel=_ELECTRICITY_FUEL,
cylinder_size=2,
cylinder_insulation_type=1,
cylinder_insulation_thickness_mm=120,
cylinder_thermostat="Y",
# Single off-peak electric immersion — drives the SAP 10.2 Table 13 HW
# high-rate split (matches the relodged after-cert; without it the HW
# bills 100% at the low rate, +1.26 SAP over the reference).
immersion_heating_type=1,
has_hot_water_cylinder=True,
meter_type="Dual",
)
# Representative heat-pump products Domna installs (one per brand we hold
# contractor install rates for), as PCDB Table 362 indices — the catalogue we
# may simulate the ASHP bundle with. Each is a valid, currently-available,
# ~5 kW air-to-water unit providing space + water heating, chosen for high SAP
# 10.2 Appendix N efficiency (space η at the dwelling's PSR, with a healthy
# water η — many high-space records collapse on water and were rejected):
#
# Vaillant 110257 aroTHERM plus 5 kW space ~402% / water ~288%
# Mitsubishi 104570 Ecodan PUZ-WM50VHA 5.0 kW space ~368% / water ~288%
# Daikin 105008 Altherma ERGA04DVA 5.5 kW space ~376% / water ~288%
# Samsung 108774 AE050CXYDEK 5 kW (R290) space ~394% / water ~309%
# Grant 103768 AERONA3 HPID6R32 4.8 kW space ~395% / water ~332%
#
# We fix the Vaillant for the tracer: it is widely available for install and a
# strong all-round SAP performer. (Promoting this to a per-dwelling choice is a
# clean future change — see the sizing note below.)
_VAILLANT_AROTHERM_PLUS_5KW_PCDB = 110257
# NOTE (sizing): the bundle installs ONE fixed ~5 kW product regardless of the
# dwelling. SAP 10.2 Appendix N reads heat-pump efficiency at the dwelling's PSR
# (= pump max output / design heat loss), so a fixed output is a deliberate
# simplification: a 5 kW unit lands at a good PSR (~0.8-1.0) for modest
# dwellings but is undersized for high-heat-loss ones (low PSR → lower space
# efficiency), leaving SAP on the table. Sizing the pump to the dwelling (and
# selecting the matching PCDB record) is future work — it also feeds the
# size-banded ASHP costing.
# The ASHP bundle's absolute end-state (ADR-0024): the fixed, representative,
# contractor-installable heat pump above (RdSAP category 4) with time-and-
# temperature-zone control (2210), a heat-pump hot-water cylinder, a single
# (non off-peak) meter, and the dwelling switched off mains gas. The index is
# the efficiency anchor — the applicator clears any stale `sap_main_heating_code`
# when an index is set, so the calculator resolves the heat pump's SCOP from the
# PCDB record. Pinned against the relodged after-cert.
_ASHP_OVERLAY = HeatingOverlay(
main_fuel_type=_ELECTRICITY_FUEL,
main_heating_control=2210,
main_heating_index_number=_VAILLANT_AROTHERM_PLUS_5KW_PCDB,
main_heating_category=_HEAT_PUMP_CATEGORY,
# Hot water from the main heat-pump system via the new cylinder (code 901,
# "from main system"). Set absolutely so a combi (909/611) or electric
# (903/908) before is reset to the fixed HP end-state, not just the case
# where the before already lodged 901.
water_heating_code=901,
water_heating_fuel=_ELECTRICITY_FUEL,
cylinder_size=4,
cylinder_insulation_type=1,
cylinder_insulation_thickness_mm=50,
cylinder_thermostat="Y",
has_hot_water_cylinder=True,
meter_type="Single",
mains_gas=False,
)
# --- Gas boiler upgrade (Heating/HW expansion): replace an existing wet boiler
# with a modern gas condensing boiler. Validated against Elmhurst before/after
# re-lodgements (cert 001431): the upgrade always targets mains gas — gas->gas
# directly, and a non-gas wet boiler (oil/LPG/solid) ->gas ONLY where a mains-gas
# connection is present (electric boilers are left alone; electrification is the
# national target). The end-state is a Table 4b SAP code (not a PCDB index): code
# 102 for a regular boiler heating a hot-water cylinder, code 104 for a combi
# (no cylinder, a later slice). The calculator derives the condensing-boiler
# seasonal efficiency from the code, so no efficiency input is needed. ---
# Mains-gas main/water fuel code (Elmhurst -> SAP10 Table 12).
_MAINS_GAS_FUEL = 26
# Table 4a heat-emitter code for radiators (the wet-distribution end-state).
_RADIATOR_EMITTER = 1
# Table 4b SAP main-heating codes for the new gas condensing boiler: code 102
# for a regular boiler heating a cylinder, code 104 for a combi (no cylinder).
_REGULAR_GAS_BOILER_SAP_CODE = 102
_COMBI_GAS_BOILER_SAP_CODE = 104
# Water-heating code 901 — hot water from the main heating system.
_WATER_FROM_MAIN_SYSTEM_CODE = 901
# Elmhurst boiler flue type for the new condensing boiler (room-sealed/balanced);
# every relodged after lodges type 2. SAP-inert, written for end-state fidelity.
_CONDENSING_BOILER_FLUE_TYPE = 2
# Controls upgrade (SAP 10.2 Table 4e Group 1, PDF p.172): bring an inadequate
# boiler control up to full programmer + room thermostat + TRVs (code 2106).
# "Inadequate" = the Group-1 codes whose description carries NO room thermostat
# (2101 no control, 2102 programmer-only, 2107/2108/2109 programmer+TRVs without
# a room thermostat, 2111 TRVs and bypass) — these lack boiler interlock (Table
# 4c(2) / footnote c)), so adding a room thermostat is a genuine improvement.
# Controls with a room thermostat (2103/2104/2105/2106/2113) or better time-and-
# temperature zone control (2110/2112) are left unchanged — never downgraded.
_FULL_BOILER_CONTROL = 2106
_INADEQUATE_BOILER_CONTROL_CODES: frozenset[int] = frozenset(
{2101, 2102, 2107, 2108, 2109, 2111}
)
# System tune-up control end-states (SAP 10.2 Table 4e Group 1): the two best
# competing control upgrades offered while KEEPING the existing boiler —
# "standard" (programmer + room thermostat + TRVs, code 2106) and "zone"
# (time-and-temperature zone control, code 2110, type 3). Zone gives more SAP
# uplift for more cost, so the Optimiser steps to it when its extra SAP is
# needed (ADR-0024).
_STANDARD_CONTROL = _FULL_BOILER_CONTROL # 2106
_ZONE_CONTROL = 2110
# Controls already providing standard (2106) or better — a standard tune-up
# would be a no-op or a downgrade, so it is not offered to these.
_STANDARD_OR_BETTER_CONTROL_CODES: frozenset[int] = frozenset({2106, 2110, 2112})
# Controls already providing zone control (type 3) — a zone tune-up is not
# offered to these.
_ZONE_CONTROL_CODES: frozenset[int] = frozenset({2110, 2112})
# Wet-boiler SAP main_heating_code ranges (SAP 10.2 Table 4a + 4b): gas/oil
# boilers 101-141, solid-fuel boilers 151-161, electric boilers 191-196 (held
# locally so the generator does not depend on the calculator's internals,
# mirroring `domain/sap10_calculator/rdsap/cert_to_inputs.py`). Electric boilers
# are a wet system but are deliberately not upgraded to gas.
_WET_BOILER_SAP_CODE_RANGES: tuple[range, ...] = (
range(101, 142),
range(151, 162),
range(191, 197),
)
_ELECTRIC_BOILER_SAP_CODE_RANGE = range(191, 197)
# Cylinder jacket end-state (from the after-cert): an 80 mm jacket
# (`cylinder_insulation_type=2`). The jacket is added only when the existing
# cylinder is below this thickness — bringing every cylinder up to 80 mm and
# never downgrading a better-insulated one.
_CYLINDER_JACKET_INSULATION_TYPE = 2
_MIN_CYLINDER_INSULATION_MM = 80
# The new condensing boiler's winter efficiency: SAP 10.2 Table 4b codes 102
# (regular condensing) and 104 (condensing combi) both lodge 84% winter. A
# like-for-like gas swap onto an existing gas boiler that already meets this
# gains nothing, so it is not offered (the dwelling gets a tune-up instead). The
# gate is gas-only: a non-gas boiler → gas is a fuel switch whose value is not
# captured by winter efficiency alone, so it is never suppressed on efficiency.
_NEW_BOILER_WINTER_EFFICIENCY_PCT = 84.0
# --- ASHP cost interpretation (ADR-0025): read the dwelling into the typed
# inputs the catalogue math needs. The modelling-layer half of the split; the
# pricing itself lives on `Products`. ---
# A dwelling at or below this floor area is treated as a 1-2 bed property (only
# affects the electric-storage decommission line — a £270 swing).
_SMALL_PROPERTY_MAX_M2 = 75.0
# Design heat loss proxy: industry rule of thumb ~50 W per m2 of floor area.
# The cost pump-size band is a minor lever, so this floor-area proxy is used in
# preference to the calculator's HLC (ADR-0025).
_KW_PER_M2 = 0.05
# Radiators ~= habitable rooms + kitchen + hall + bathroom (RdSAP excludes the
# latter three from habitable rooms); fallback ~1 radiator per 13 m2.
_RADIATOR_ROOM_OFFSET = 3
_RADIATOR_M2_PER_RADIATOR = 13.0
# main_fuel_type codes (gov API enum and/or Table 12) by fuel. Classification
# keys on the heating *fuel*, NOT the `mains_gas` flag — that flag means gas is
# available at the property, which is True even for electrically-heated dwellings
# on a gas street (every 001431 electric fixture lodges mains_gas=True).
_GAS_FUEL_CODES = frozenset({26, 1})
_OIL_FUEL_CODES = frozenset({28, 4, 71, 73, 75, 76})
_LPG_FUEL_CODES = frozenset({27, 2, 3, 5, 9})
def ashp_cost_inputs(epc: EpcPropertyData) -> AshpCostInputs:
"""Read an `EpcPropertyData` into the typed inputs `Products.ashp_bundle_cost`
needs: the existing system, property-size band, design heat loss (floor-area
proxy), radiator count, and whether a wet system can be reused (ADR-0025)."""
system: AshpExistingSystem = _existing_system(epc)
floor_area: float = epc.total_floor_area_m2
return AshpCostInputs(
existing_system=system,
is_small_property=floor_area <= _SMALL_PROPERTY_MAX_M2,
design_heat_loss_kw=floor_area * _KW_PER_M2,
radiator_count=_radiator_count(epc),
has_reusable_wet_system=system
in (AshpExistingSystem.GAS, AshpExistingSystem.OIL, AshpExistingSystem.LPG),
)
def _existing_system(epc: EpcPropertyData) -> AshpExistingSystem:
"""Classify the dwelling's pre-retrofit system for decommission + reuse,
keyed on the heating *fuel code* (not the misleading `mains_gas` flag).
Electricity, gas, oil and LPG map to their categories; a dwelling with no
lodged main system to NONE; anything unrecognised to OTHER (which prices the
gas-line decommission fallback). The storage-vs-other-electric split is
deliberately not made — both price the same decommission line (ADR-0025)."""
details: list[MainHeatingDetail] = epc.sap_heating.main_heating_details
if not details:
return AshpExistingSystem.NONE
fuel = details[0].main_fuel_type
if fuel == _ELECTRICITY_FUEL:
return AshpExistingSystem.ELECTRIC_STORAGE
if fuel in _GAS_FUEL_CODES:
return AshpExistingSystem.GAS
if fuel in _OIL_FUEL_CODES:
return AshpExistingSystem.OIL
if fuel in _LPG_FUEL_CODES:
return AshpExistingSystem.LPG
return AshpExistingSystem.OTHER
def _radiator_count(epc: EpcPropertyData) -> int:
"""Estimate radiators from habitable rooms (+ kitchen/hall/bathroom), or
from floor area when the room count is missing (ADR-0025). Products clamps
to its distribution table bounds."""
habitable: int = epc.habitable_rooms_count
if habitable > 0:
return habitable + _RADIATOR_ROOM_OFFSET
return round(epc.total_floor_area_m2 / _RADIATOR_M2_PER_RADIATOR)
def recommend_heating(
epc: EpcPropertyData,
products: ProductRepository,
restrictions: PlanningRestrictions = PlanningRestrictions(),
considered_measures: Optional[frozenset[MeasureType]] = None,
) -> Optional[Recommendation]:
"""Return a "Heating & Hot Water" Recommendation of competing whole-system
bundles for the dwelling, else None when no bundle is eligible. ASHP is
additionally gated by the Property's planning protections (ADR-0024)."""
options: list[MeasureOption] = []
hhr_option = _hhr_storage_option(epc, products)
if hhr_option is not None:
options.append(hhr_option)
ashp_option = _ashp_option(epc, products, restrictions)
if ashp_option is not None:
options.append(ashp_option)
boiler_option = _boiler_upgrade_option(epc, products)
if boiler_option is not None:
options.append(boiler_option)
options.extend(_system_tune_up_options(epc, products, considered_measures))
if not options:
return None
return Recommendation(surface=_HEATING_SURFACE, options=tuple(options))
def _system_tune_up_options(
epc: EpcPropertyData,
products: ProductRepository,
considered_measures: Optional[frozenset[MeasureType]] = None,
) -> list[MeasureOption]:
"""The system tune-up options: keep the existing wet boiler but install
better heating controls (standard 2106 and/or zone 2110, as competing
options) and fix the cylinder (jacket when under-insulated, thermostat when
absent). Each control option is offered only when it genuinely improves the
existing controls — never a downgrade or a no-op (ADR-0024)."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
code: Optional[int] = main.sap_main_heating_code
if code is None or not any(code in r for r in _WET_BOILER_SAP_CODE_RANGES):
return []
control = main.main_heating_control
control_code: Optional[int] = control if isinstance(control, int) else None
options: list[MeasureOption] = []
if control_code not in _STANDARD_OR_BETTER_CONTROL_CODES:
options.append(
_tune_up_option(
epc,
products,
measure_type=_SYSTEM_TUNE_UP_MEASURE_TYPE,
control=_STANDARD_CONTROL,
description=(
"Tune up the heating: install a programmer, room thermostat "
"and TRVs and insulate and thermostat the hot-water cylinder"
),
)
)
if control_code not in _ZONE_CONTROL_CODES and (
considered_measures is None
or _SYSTEM_TUNE_UP_ZONED_MEASURE_TYPE in considered_measures
):
options.append(
_tune_up_option(
epc,
products,
measure_type=_SYSTEM_TUNE_UP_ZONED_MEASURE_TYPE,
control=_ZONE_CONTROL,
description=(
"Tune up the heating: install time-and-temperature zone "
"control and insulate and thermostat the hot-water cylinder"
),
)
)
return options
def _tune_up_option(
epc: EpcPropertyData,
products: ProductRepository,
*,
measure_type: MeasureType,
control: int,
description: str,
) -> MeasureOption:
"""One tune-up Option: the existing boiler is kept; only the heating control
and the conditional cylinder fixes change. Cost is composed per dwelling from
those components (ADR-0027); the catalogue row is read for its id."""
product = products.get(measure_type)
cost: Cost = Products().tune_up_cost(
tune_up_cost_inputs(epc, is_zoned=control == _ZONE_CONTROL)
)
return MeasureOption(
measure_type=measure_type,
description=description,
overlay=EpcSimulation(heating=_tune_up_overlay(epc, control)),
cost=cost,
material_id=product.id,
)
def _tune_up_overlay(epc: EpcPropertyData, control: int) -> HeatingOverlay:
"""Build a tune-up end-state: set the heating control to ``control`` and
apply the conditional cylinder fixes (an 80 mm jacket when under-insulated, a
thermostat when absent) — only when the dwelling has a cylinder. The boiler,
fuel and meter are left unchanged (the boiler is kept)."""
sap_heating = epc.sap_heating
jacket_type: Optional[int] = None
jacket_thickness_mm: Optional[int] = None
thermostat: Optional[str] = None
if epc.has_hot_water_cylinder:
if _cylinder_under_insulated(sap_heating.cylinder_insulation_thickness_mm):
jacket_type = _CYLINDER_JACKET_INSULATION_TYPE
jacket_thickness_mm = _MIN_CYLINDER_INSULATION_MM
if sap_heating.cylinder_thermostat != "Y":
thermostat = "Y"
return HeatingOverlay(
main_heating_control=control,
cylinder_insulation_type=jacket_type,
cylinder_insulation_thickness_mm=jacket_thickness_mm,
cylinder_thermostat=thermostat,
)
def _boiler_upgrade_option(
epc: EpcPropertyData, products: ProductRepository
) -> Optional[MeasureOption]:
"""The gas-condensing-boiler upgrade for a dwelling with an existing wet
boiler: a combi (Table 4b code 104) where there is no cylinder, or a regular
boiler (code 102) heating the existing cylinder where there is one. Both
upgrade inadequate controls and the cylinder variant adds the conditional
cylinder fixes (a jacket when under-insulated, a thermostat when absent). One
Option per dwelling — a dwelling has a cylinder or it does not — offered only
where a mains-gas connection makes the gas end-state installable (ADR-0024
revised)."""
if not _boiler_upgrade_eligible(epc):
return None
has_cylinder: bool = epc.has_hot_water_cylinder
overlay: HeatingOverlay = (
_boiler_cylinder_overlay(epc) if has_cylinder else _boiler_combi_overlay(epc)
)
description: str = (
"Replace the boiler with a gas condensing boiler and insulate and "
"thermostat the hot-water cylinder"
if has_cylinder
else "Replace the boiler with a gas condensing combi boiler"
)
# Cost is composed per dwelling from the boiler + the controls/cylinder
# fixes the overlay installs (ADR-0027), not the flat catalogue scalar; the
# catalogue row is still read for its id.
product = products.get(_GAS_BOILER_UPGRADE_MEASURE_TYPE)
cost: Cost = Products().boiler_bundle_cost(boiler_cost_inputs(epc))
return MeasureOption(
measure_type=_GAS_BOILER_UPGRADE_MEASURE_TYPE,
description=description,
overlay=EpcSimulation(heating=overlay),
cost=cost,
material_id=product.id,
)
def _boiler_upgrade_eligible(epc: EpcPropertyData) -> bool:
"""Whether a dwelling's existing wet boiler can be upgraded to a gas
condensing boiler. The gas end-state is installable only with a mains-gas
connection, so gas dwellings always qualify and a non-gas wet boiler
(oil/LPG/solid) qualifies only where mains gas is present. Electric boilers
are left alone — electrification, not a gas swap, is their upgrade path. A
gas boiler that already meets the new condensing efficiency is not re-offered
a like-for-like swap (it gains nothing — the dwelling gets a tune-up
instead); a non-gas boiler is a fuel switch, so it is never gated on
efficiency."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
code: Optional[int] = main.sap_main_heating_code
if code is None:
return False
if not any(code in r for r in _WET_BOILER_SAP_CODE_RANGES):
return False
if code in _ELECTRIC_BOILER_SAP_CODE_RANGE:
return False
if not epc.sap_energy_source.mains_gas:
return False
if main.main_fuel_type in _GAS_FUEL_CODES and _already_condensing(code):
return False
return True
def _already_condensing(sap_main_heating_code: int) -> bool:
"""Whether an existing gas boiler already meets the new condensing boiler's
winter efficiency (SAP 10.2 Table 4b). Non-Table-4b codes (e.g. solid fuel)
have no comparable efficiency and so are never treated as already-condensing."""
efficiencies: Optional[tuple[float, float]] = table_4b_seasonal_efficiencies_pct(
sap_main_heating_code
)
if efficiencies is None:
return False
winter_efficiency_pct: float = efficiencies[0]
return winter_efficiency_pct >= _NEW_BOILER_WINTER_EFFICIENCY_PCT
def _boiler_combi_overlay(epc: EpcPropertyData) -> HeatingOverlay:
"""Build the per-dwelling combi end-state: a gas condensing combi (Table 4b
code 104, fanned flue) on radiators with hot water from the boiler, plus a
controls upgrade when the existing controls are inadequate. No cylinder, so
no cylinder fields are touched."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
return HeatingOverlay(
main_fuel_type=_MAINS_GAS_FUEL,
heat_emitter_type=_RADIATOR_EMITTER,
sap_main_heating_code=_COMBI_GAS_BOILER_SAP_CODE,
fan_flue_present=True,
boiler_flue_type=_CONDENSING_BOILER_FLUE_TYPE,
main_heating_control=_upgraded_boiler_control(main),
water_heating_code=_WATER_FROM_MAIN_SYSTEM_CODE,
water_heating_fuel=_MAINS_GAS_FUEL,
)
def _boiler_cylinder_overlay(epc: EpcPropertyData) -> HeatingOverlay:
"""Build the per-dwelling boiler-with-cylinder end-state: a regular gas
condensing boiler on radiators, hot water from the main system, a controls
upgrade when the existing controls are inadequate, and the conditional
cylinder fixes — an 80 mm jacket only when the cylinder is under-insulated, a
thermostat only when one is absent. The existing cylinder size and meter are
left unchanged."""
sap_heating = epc.sap_heating
main: MainHeatingDetail = sap_heating.main_heating_details[0]
jacket_type: Optional[int] = None
jacket_thickness_mm: Optional[int] = None
if _cylinder_under_insulated(sap_heating.cylinder_insulation_thickness_mm):
jacket_type = _CYLINDER_JACKET_INSULATION_TYPE
jacket_thickness_mm = _MIN_CYLINDER_INSULATION_MM
thermostat: Optional[str] = (
"Y" if sap_heating.cylinder_thermostat != "Y" else None
)
return HeatingOverlay(
main_fuel_type=_MAINS_GAS_FUEL,
heat_emitter_type=_RADIATOR_EMITTER,
sap_main_heating_code=_REGULAR_GAS_BOILER_SAP_CODE,
fan_flue_present=True,
boiler_flue_type=_CONDENSING_BOILER_FLUE_TYPE,
main_heating_control=_upgraded_boiler_control(main),
water_heating_code=_WATER_FROM_MAIN_SYSTEM_CODE,
water_heating_fuel=_MAINS_GAS_FUEL,
cylinder_insulation_type=jacket_type,
cylinder_insulation_thickness_mm=jacket_thickness_mm,
cylinder_thermostat=thermostat,
has_hot_water_cylinder=True,
)
def _cylinder_under_insulated(thickness_mm: Optional[int]) -> bool:
"""Whether a hot-water cylinder is below the 80 mm jacket end-state (an
un-jacketed cylinder lodges no thickness)."""
return thickness_mm is None or thickness_mm < _MIN_CYLINDER_INSULATION_MM
def _upgraded_boiler_control(main: MainHeatingDetail) -> Optional[int]:
"""The full-controls code (2106) when the existing boiler control is
inadequate (lacks a room thermostat — SAP 10.2 Table 4e Group 1), else
``None`` to leave a room-thermostatted or better control unchanged. So the
overlay only ever moves controls where it genuinely improves them."""
control = main.main_heating_control
code: Optional[int] = control if isinstance(control, int) else None
if code is None and isinstance(control, str) and control.isdigit():
code = int(control)
if code in _INADEQUATE_BOILER_CONTROL_CODES:
return _FULL_BOILER_CONTROL
return None
# --- Boiler / tune-up cost interpretation (ADR-0027): read the dwelling into the
# typed inputs the catalogue math needs. The pricing itself lives on `Products`;
# this is the modelling-layer half that the catalogue stays free of. ---
# SAP 10.2 Table 4e Group 1 (PDF p.172) — which standard-control parts each
# boiler control code already provides: (has_programmer, has_room_thermostat,
# has_TRVs). Lets the standard-controls cost charge only the missing parts to
# reach 2106 (programmer + room thermostat + TRVs). Zone codes (2110/2112) are
# omitted — a standard upgrade is never offered to them.
_CONTROL_FEATURES_BY_CODE: dict[int, tuple[bool, bool, bool]] = {
2101: (False, False, False), # No time or thermostatic control
2102: (True, False, False), # Programmer, no room thermostat
2103: (False, True, False), # Room thermostat only
2104: (True, True, False), # Programmer and room thermostat
2105: (True, True, False), # Programmer and at least two room thermostats
2106: (True, True, True), # Programmer, room thermostat and TRVs
2107: (True, False, True), # Programmer, TRVs and bypass
2108: (True, False, True), # Programmer, TRVs and flow switch
2109: (True, False, True), # Programmer, TRVs and boiler energy manager
2111: (False, False, True), # TRVs and bypass
2113: (False, True, True), # Room thermostat and TRVs
}
def _control_features(main: MainHeatingDetail) -> tuple[bool, bool, bool]:
"""The standard-control parts a dwelling already has, from its SAP control
code. An unrecognised/absent code defaults to none present (charge the full
standard kit) — conservative, and the standard option is only offered when
the control is improvable anyway."""
control = main.main_heating_control
code: Optional[int] = control if isinstance(control, int) else None
return _CONTROL_FEATURES_BY_CODE.get(code, (False, False, False)) if (
code is not None
) else (False, False, False)
def _cylinder_fix_needs(epc: EpcPropertyData) -> tuple[bool, bool]:
"""Whether the dwelling needs a cylinder jacket and/or a thermostat — the
same predicates the overlay uses (only when a cylinder exists)."""
if not epc.has_hot_water_cylinder:
return (False, False)
sap_heating = epc.sap_heating
needs_jacket: bool = _cylinder_under_insulated(
sap_heating.cylinder_insulation_thickness_mm
)
needs_thermostat: bool = sap_heating.cylinder_thermostat != "Y"
return (needs_jacket, needs_thermostat)
def tune_up_cost_inputs(epc: EpcPropertyData, *, is_zoned: bool) -> TuneUpCostInputs:
"""Read a dwelling into the inputs `Products.tune_up_cost` needs: the control
level, the radiator count (per-radiator items), the standard-control parts
already fitted, and the cylinder fixes that apply (ADR-0027)."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
has_programmer, has_room_thermostat, has_trvs = _control_features(main)
needs_jacket, needs_thermostat = _cylinder_fix_needs(epc)
return TuneUpCostInputs(
is_zoned=is_zoned,
radiator_count=_radiator_count(epc),
has_programmer=has_programmer,
has_room_thermostat=has_room_thermostat,
has_trvs=has_trvs,
needs_cylinder_jacket=needs_jacket,
needs_cylinder_thermostat=needs_thermostat,
)
def boiler_cost_inputs(epc: EpcPropertyData) -> BoilerCostInputs:
"""Read a dwelling into the inputs `Products.boiler_bundle_cost` needs: the
boiler is always priced; controls are added only when the upgrade fires a
controls change, and the cylinder fixes when applicable (ADR-0027)."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
has_programmer, has_room_thermostat, has_trvs = _control_features(main)
needs_jacket, needs_thermostat = _cylinder_fix_needs(epc)
return BoilerCostInputs(
upgrades_controls=_upgraded_boiler_control(main) is not None,
radiator_count=_radiator_count(epc),
has_programmer=has_programmer,
has_room_thermostat=has_room_thermostat,
has_trvs=has_trvs,
needs_cylinder_jacket=needs_jacket,
needs_cylinder_thermostat=needs_thermostat,
)
def _ashp_option(
epc: EpcPropertyData,
products: ProductRepository,
restrictions: PlanningRestrictions,
) -> Optional[MeasureOption]:
"""The air-source heat-pump bundle, offered for any non-flat house/bungalow
that is not listed/heritage and not already a heat pump."""
if not _ashp_eligible(epc, restrictions):
return None
# Cost is composed per-dwelling from the rate sheet (ADR-0025), not the
# single catalogue scalar; the catalogue row is read only for its id, so an
# absent ASHP row must not suppress the bundle — it just carries no id.
product: Optional[Product] = products.get_optional(_ASHP_MEASURE_TYPE)
cost: Cost = Products().ashp_bundle_cost(ashp_cost_inputs(epc))
return MeasureOption(
measure_type=_ASHP_MEASURE_TYPE,
description=(
"Replace the heating with an air-source heat pump, time-and-"
"temperature-zone controls and a heat-pump hot-water cylinder"
),
overlay=EpcSimulation(heating=_ASHP_OVERLAY),
cost=cost,
material_id=product.id if product is not None else None,
)
def _ashp_eligible(epc: EpcPropertyData, restrictions: PlanningRestrictions) -> bool:
"""ASHP suits any non-flat house/bungalow that is not already a heat pump and
is not fabric-protected. Eligibility encodes only physical/planning
installability — the Optimiser owns the economics (ADR-0024), so floor area,
built form, fuel, and fabric are deliberately not gates. A conservation area
does not exclude ASHP (offered with a planning caveat); a listed/heritage
protection (`blocks_internal`) does."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
if main.main_heating_category == _HEAT_PUMP_CATEGORY:
return False
if restrictions.blocks_internal:
return False
return _is_house_or_bungalow(epc)
def _is_house_or_bungalow(epc: EpcPropertyData) -> bool:
"""Whether the dwelling is a house or bungalow (not a flat/maisonette). The
Elmhurst path lodges the name; the API path a stringified RdSAP code
(`PROPERTY_TYPE_LOOKUP`: 0 House, 1 Bungalow, 2 Flat, 3 Maisonette)."""
raw: str = (epc.property_type or "").strip()
if raw.lower() in ("house", "bungalow"):
return True
if raw.isdigit():
return PROPERTY_TYPE_LOOKUP.get(int(raw)) in ("House", "Bungalow")
return False
def _hhr_storage_option(
epc: EpcPropertyData, products: ProductRepository
) -> Optional[MeasureOption]:
"""The high-heat-retention storage bundle, offered for an electrically-heated
(or off-gas) dwelling that is not already HHR or a heat pump."""
if not _hhr_storage_eligible(epc):
return None
product = products.get(_HHR_STORAGE_MEASURE_TYPE)
return MeasureOption(
measure_type=_HHR_STORAGE_MEASURE_TYPE,
description=(
"Replace the heating with high heat retention storage heaters on an "
"off-peak tariff, with an off-peak electric hot-water cylinder"
),
overlay=EpcSimulation(heating=_HHR_STORAGE_OVERLAY),
cost=Cost(
total=product.unit_cost_per_m2, contingency_rate=product.contingency_rate
),
material_id=product.id,
)
def _hhr_storage_eligible(epc: EpcPropertyData) -> bool:
"""HHR storage suits an electrically-heated or off-gas dwelling, unless it is
already HHR or a heat pump (translated from legacy `HeatingRecommender.
is_high_heat_retention_valid`, which keyed on description strings)."""
main: MainHeatingDetail = epc.sap_heating.main_heating_details[0]
if main.sap_main_heating_code == _HHR_STORAGE_SAP_CODE:
return False
if main.main_heating_category == _HEAT_PUMP_CATEGORY:
return False
off_gas: bool = not epc.sap_energy_source.mains_gas
electric_main: bool = main.main_fuel_type == _ELECTRICITY_FUEL
return electric_main or off_gas
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