SAP 10.2 Table 12a Grid 2 (PDF p.191) splits off-peak electricity
costs into two categories:
Other electricity uses Tariff Fraction at
high rate
Fans for mechanical ventilation systems 7-hour 0.71
10-hour 0.58
All other uses, and locally generated 7-hour 0.90
electricity 10-hour 0.80
Cert 000565 (Dual meter, 10-hour off-peak, MEV decentralised) lodges
127.5159 kWh of MEV-fan electricity (line 230a) that bills at the
`FANS_FOR_MECH_VENT` blend (0.58 × 14.68 + 0.42 × 7.50 = 11.6644
p/kWh), distinct from the 125 kWh of other pumps_fans (45 kWh gas-
boiler flue fan + 80 kWh solar HW pump) which bills at the
`ALL_OTHER_USES` blend (0.80 × 14.68 + 0.20 × 7.50 = 13.2440 p/kWh).
Pre-slice the cascade applied `ALL_OTHER_USES` to ALL 252.5159 kWh,
over-counting MEV cost by 127.5159 × (0.13244 - 0.11664) = +£2.01/yr.
Worksheet pin verification (line (249)):
"Pumps, fans and electric keep-hot ... 172.5159 13.2440 20.8338"
127.5159 × 0.11664 + 45 × 0.13244 = £14.8753 + £5.9598 = £20.8351
≈ ws £20.8338 ✓
Pump for solar water heating 80.0 × 0.13244 = £10.5952 ✓
Implementation (3-layer):
1. `calculator.py:CalculatorInputs` — new optional
`pumps_fans_fuel_cost_gbp_per_kwh: Optional[float] = None`.
2. `calculator.py` legacy cost path — `pumps_fans_cost` resolves
via the new field with fallback to `other_fuel_cost_gbp_per_kwh`.
3. `cert_to_inputs.py:_pumps_fans_fuel_cost_gbp_per_kwh` — computes
the kWh-weighted blended rate when off-peak + MEV is lodged.
Reuses `_mev_decentralised_kwh_per_yr_from_cert` (S0380.102) to
recover the MEV portion.
Cohort safety: STANDARD-tariff certs (the entire cohort except cert
000565) get None back → existing `other_fuel_cost_gbp_per_kwh`
fallback unchanged. Certs without MEV (zero MEV kWh) also get None
→ no behavioural change.
Movement at HEAD (cert 000565):
- pumps_fans_kwh_per_yr ✓ EXACT (unchanged)
- total_fuel_cost_gbp: 4680.6514 → 4678.6372 (Δ +£0.39 → -£1.62)
- ecf: 5.3873 → 5.3850 (Δ +0.0007 → -0.0016)
- sap_score_continuous: 28.5043 → 28.5269 (Δ -0.0044 → +0.0182)
Continuous-SAP residual drifted from -0.0044 to +0.0182 in absolute
value: closing the MEV cost over-count exposes a pre-existing
space-heating cascade under-count (main_heating_fuel_kwh is -16 kWh
under ws). Per user direction [[feedback-spec-floor-skepticism]]:
shipping spec-correct intermediate-value fixes even when they
transiently drift continuous SAP. The remaining residual is now
SH-cascade driven; a separate slice.
Test count: 597 pass + 7 expected 000565 fails unchanged.
Pyright net-zero per touched file.
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