junte/Model
1
0
Fork 0
mirror of https://github.com/Hestia-Homes/Model.git synced 2026-07-12 13:29:04 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Electric underfloor codes resolve their SAP 10.2 Table 12a Grid 1 rows 🟩

Browse source 
421 slab -> Other storage heaters (0.00); 422/423 integrated -> 0.20;
424/425 screed/timber -> 0.90/0.50 — per the Grid 1 row labels that name
the codes (PDF p.184). Closes the None all-low-rate fallback that
over-credited 7-hour-metered underfloor dwellings.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Khalim Conn-Kowlessar 2026-07-03 16:00:40 +00:00
parent f604672ae0
commit 6c6be1a432
1 changed files with 33 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
domain/sap10_calculator/rdsap/cert_to_inputs.py
View file

@ -2603,6 +2603,23 @@ _ELECTRIC_STORAGE_BOILER_CODES: Final[frozenset[int]] = frozenset(
{193, 194, 195, 196}
)
_ELECTRIC_CPSU_CODES: Final[frozenset[int]] = frozenset({192})
# Electric underfloor (Table 4a 421-425) — SAP 10.2 Table 12a Grid 1 (PDF
# p.184) names the codes in its row labels:
# 422/423 "Integrated (storage+direct-acting) systems (applies to storage
# heaters 408 and underfloor heating 422 and 423)" → 7-hour 0.20
# 424/425 "Underfloor heating (in screed above insulation, in timber floor
# or immediately below floor covering)" → 7-hour 0.90 / 10-hour 0.50
# 421 "in concrete slab (off-peak only)" is named in NEITHER underfloor
# row — the slab is the storage medium, so it takes the "Other
# storage heaters" row (0.00 at 7-hour or 24-hour), consistent with
# §12 Rule 2 listing 421 among the off-peak-implying storage codes.
# Before these branches every underfloor code fell to the None all-low-rate
# fallback, over-crediting a 7-hour screed dwelling's space heat at 5.50p/kWh
# instead of the blended ~14.3p (ADR-0050 deferred follow-up; 22 live
# 7-hour-metered underfloor dwellings on portfolio 796).
_SLAB_UNDERFLOOR_CODES: Final[frozenset[int]] = frozenset({421})
_INTEGRATED_UNDERFLOOR_CODES: Final[frozenset[int]] = frozenset({422, 423})
_SCREED_OR_TIMBER_UNDERFLOOR_CODES: Final[frozenset[int]] = frozenset({424, 425})
def _table_12a_system_for_main(
@ -2622,7 +2639,9 @@ def _table_12a_system_for_main(
- ASHP / GSHP (codes 211-224, 521-524, PCDB index) — wired
- Storage heaters (cat 7): 408 → INTEGRATED_STORAGE_DIRECT (0.20),
all others → OTHER_STORAGE_HEATERS (0.00) — wired
- Underfloor heating (421-422) — TODO
- Underfloor heating: 421 slab → OTHER_STORAGE_HEATERS (0.00),
422/423 integrated → INTEGRATED_STORAGE_DIRECT (0.20),
424/425 screed/timber → UNDERFLOOR_HEATING (0.90/0.50) — wired
- Direct-acting electric boiler (191) → 0.90/0.50; electric storage
boilers (193/194/195/196) → 0.00 — wired
- Electric CPSU (192) — Appendix F high-rate cascade still TODO
@ -2634,6 +2653,19 @@ def _table_12a_system_for_main(
main.main_heating_index_number is not None
and heat_pump_record(main.main_heating_index_number) is not None
)
# Electric UNDERFLOOR heating — routed by the Table 4a code per the Grid 1
# row labels (see `_SLAB_UNDERFLOOR_CODES` et al. above), checked BEFORE
# the storage branch so a stale category 7 cannot drag a screed system
# (0.90 at 7-hour) down to the all-night storage row — the code is more
# authoritative than the coarser category, mirroring the storage-over-
# room-heater precedent below. Gated on `_is_electric_main` belt-and-braces.
if _is_electric_main(main) and code is not None:
if code in _SCREED_OR_TIMBER_UNDERFLOOR_CODES:
return Table12aSystem.UNDERFLOOR_HEATING
if code in _INTEGRATED_UNDERFLOOR_CODES:
return Table12aSystem.INTEGRATED_STORAGE_DIRECT
if code in _SLAB_UNDERFLOOR_CODES:
return Table12aSystem.OTHER_STORAGE_HEATERS
# Electric STORAGE heaters — SAP 10.2 Table 12a Grid 1 (PDF p.191).
# Detected by RdSAP main_heating_category 7 OR, authoritatively, by a Table
# 4a electric-storage-heater SAP code (401-409). Keyed on the CODE as well as