1cb85c592f
SAP 10.2 Table 11 (PDF p.188) "Fraction of heat supplied by
secondary heating systems" — the "Electric storage heaters (not
integrated)" row splits by Table 4a sub-type:
- not fan-assisted: 0.15
- fan-assisted: 0.10
- high heat retention (as defined in 9.2.8): 0.10
Plus separate rows:
Integrated storage/direct-acting electric systems: 0.10
Electric room heaters: 0.20
Other electric systems (e.g. underfloor): 0.10
Cross-referenced with SAP 10.2 Table 4a (PDF p.166) Electric
storage codes:
401: Old (large volume) storage heaters — not fan-assisted
402: Slimline storage heaters — not fan-assisted
403: Convector storage heaters — not fan-assisted
404: Fan storage heaters — fan-assisted
405: Slimline + Celect — not fan-assisted
406: Convector + Celect — not fan-assisted
407: Fan + Celect — fan-assisted
408: Integrated storage + direct-acting — "Integrated"
409: High heat retention — HHR
421: Underfloor heating — "Other electric"
Pre-slice the cascade defaulted `_secondary_fraction` to 0.10 for
every forced electric-storage code (Elmhurst mapper leaves
`main_heating_category=None`, dispatch falls through to the
`_SECONDARY_HEATING_FRACTION_DEFAULT` 0.10), missing the 0.15
not-fan-assisted sub-row on codes 401/402/403/405/406.
Two compounding spec-citable fixes:
(a) New `_SECONDARY_FRACTION_BY_ELECTRIC_STORAGE_CODE` dispatch dict
consulted before the category-based lookup in
`_secondary_fraction`. Routes each Table 4a 4xx code to its
Table 11 sub-row fraction.
(b) Code 408 removed from `_FORCE_SECONDARY_FOR_MAIN_CODES`.
SAP 10.2 §A.2.2 (PDF p.~189) verbatim: "This applies to main
heating codes 401 to 407, 409 and 421" — 408 is explicitly
NOT in the spec's forced list. The integrated storage+direct-
acting heater's direct-acting element acts as the secondary
already, so the calculation doesn't add another.
Corpus impact (electric variants — Elmhurst mapper path):
- electric 3 (SAP 401): sec_frac 0.10 → 0.15; CO2 -117.84 →
-108.88; PE -1121.97 → -1093.18. SAP / cost residual unchanged
because the off-peak meter routes the cost calc through the
`_ZERO_FUEL_COST_FOR_OFF_PEAK` sentinel + legacy scalar-field
math which bills main and secondary at the same off-peak low
rate (7.41 p/kWh) — main-vs-secondary split is cost-neutral.
- electric 5 (SAP 402): sec_frac 0.10 → 0.15; CO2 -11.08 → -2.48;
PE -161.03 → -133.36. Same cost-invariance.
- electric 7 (SAP 408): forced-secondary removed → cascade secondary
fuel kWh 891 → 0 (matches worksheet); CO2 -37.86 → -53.57;
PE -498.47 → -549.37. SAP residual unchanged (same off-peak
cost-invariance).
- electric 4/6/8/9: no change (categories 404/409/421 keep their
existing 0.10 dispatch).
The remaining +2.55 SAP residual on electric 3 (+1.29 on electric 7)
is now confirmed to be driven by space-heating DEMAND undercount
(cascade SH demand 10083 kWh vs worksheet 11088 kWh for electric 3;
8914 vs 9529 for electric 7), not by sec_frac dispatch. That's a
separate slice — likely §9 MIT calc or §8 gains/HLC for storage-
heater R values, follow-up after this slice.
Extended handover suite: 887 pass, 0 fail (was 886 + 1 new AAA test).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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| .devcontainer | ||
| .github/workflows | ||
| .idea | ||
| .vscode | ||
| applications | ||
| asset_list | ||
| backend | ||
| backlog | ||
| datatypes | ||
| deployment/terraform | ||
| docs/adr | ||
| domain | ||
| epr_data_exports | ||
| etl | ||
| infrastructure | ||
| model_data/requirements | ||
| orchestration | ||
| recommendations | ||
| repositories | ||
| scripts | ||
| sfr/principal_pitch | ||
| survey_report | ||
| tests | ||
| utilities | ||
| utils | ||
| .coveragerc | ||
| .dockerignore | ||
| .gitignore | ||
| __init__.py | ||
| ara_backend_design.md | ||
| BaseUtility.py | ||
| CLAUDE.md | ||
| conftest.py | ||
| CONTEXT.md | ||
| devcontainer.sh | ||
| Dockerfile.test | ||
| Dockerfile.test.dockerignore | ||
| Makefile | ||
| MEMORY.md | ||
| package-lock.json | ||
| package.json | ||
| pyproject.toml | ||
| pyrightconfig.json | ||
| pytest.ini | ||
| README.md | ||
| run_lambda_local.sh | ||
| serverless.yml | ||
| test.requirements.txt | ||
| tox.ini | ||
| UBIQUITOUS_LANGUAGE.md | ||
Model Repository
This repository contains the code pertaining to the development of the data science and machine learning products being utilised by Hestia.
The different folders in this repository relate to services that can be used independently, or can be imported and used as part of a larger application
Getting Started
Prerequisites
Dev Container Setup
This repo uses a Docker Compose-based dev container. The model-backend service joins a shared-dev Docker network so it can communicate with other local services (e.g. a frontend container) running on your machine.
VS Code users: The initializeCommand in devcontainer.json creates the shared-dev network automatically before the container starts. No manual step required — just open the repo and select Reopen in Container.
Non-VS Code / CI workflows: Run the following once before starting the container:
make dev-setup
This is idempotent and safe to re-run if the network already exists.
Folders
backend/
This folder contains the code for the fastapi backend service, which provides an interface to much of the functionality in this repository, for the frontend
model_data/
This folder contains related to the reading and preparation of assessment model data, including pulling out epc attributes
Testing
All tests can be run, against the configuration in pytest.ini running
pytest
This will run the complete panel of tests and report on coverage in the locations specified by the pytest.ini file.
To run tests in a specific service, e.g. inside of model_data, simply run
pytest --cov-config=model_data/.coveragerc --cov=model_data
This will produce the test results and coverage reports