Numbers you can check, all the way down.
Here is HeatAssure™'s working, written for the people whose job is to check. The standards say what a home should do; our verification shows what each one delivers, on one governed record.
Built by us, checked against the government's own reference.
SAP 10.3
The UK's standard method for rating home energy, and the assessment standard in force today. We run it in-house, validated end to end against approved SAP software.
Home Energy Model
The standard that replaces it. We run that in-house too, checked against the government's official implementation.
Beyond the standards
We verify what each home delivers as evidence arrives, with a stated confidence, and say so plainly when the standard and the home part company. That layer is ours, governed and versioned, and it works alongside the tools you already have.
- Every calculation we stand behind is cross-validated against the government's own reference for its method, from approved SAP software to the official Home Energy Model implementation.
The cross-validation above covers the compliance calculations, where a government reference exists to check against. The verdict layer that reads each home is ours and versioned, with its thresholds changed only through a governed process and its specification available under diligence.
The record does not die at handover.
Design tools usually stop at the standard, and operational analytics usually start cold. HeatAssure holds one record across that boundary: the design at the start is carried out to EN 12831, the same record carries the home in operation, and each end can be checked against the other.
How much rides on the design stage: one certified heat pump, one city of homes, modelled three times with only the design flow temperature changed.
- median in the home, 35 °C flow
- 5.47
- median in the home, 45 °C flow
- 4.35
- median in the home, 55 °C flow
- 3.60
Each band spans the middle 80% of homes; the tick is the median home. The two certificate figures, measured on the test rig, are marked on every rung.
The fleet beats the certificate: median 5.47 against the certificate figure of 5.0. 9.8% of homes model below it.
The certificate figure of 5.0 is out of reach for 75.1% of the fleet: median 4.35 against it.
The fleet lands on the certificate's other figure, 3.6: median 3.60, and 90.7% of homes model below the 5.0 figure.
How a cause gets named.
What a verdict can name
The cause the evidence supports: the design, the fabric, the settings, the tariff, the install or the product itself. Where the evidence cannot separate causes, the verdict says so rather than guessing.
What bounds it
Every figure carries its assumptions and their sources, so each party is judged against what they promised, on the information they had at the time, and a wrong input clears the design built on it.
When it is disputed
Anyone whose work a reading touches can put evidence on the record, and a corrected reading is republished with the change visible.
The right of reply behind that, and how much the platform is allowed to do on its own, are published on Trust.
Edge cases do not show up in ten runs.
They show up in millions. Running at housing stock scale is how we find the cases a demo never meets.
- The Home Energy Model, run at 20 million home scale.
- The same validated calculations power a reconstruction of UK housing stock covering around 18 million dwellings.
Governance is built in.
- A live governed platform: every screen resolves against a governed viewpoint, and every claim carries its validation status, including the red ones.
Certified products, not defaults.
A calculation is only as good as the product data underneath it. Below is the certified library we calculate against: 9,300 heat pumps, drawn from the public record.
We publish our reading of the government's method.
The HEM Technical Reference is Aeterno's independent documentation of the government's Home Energy Model, stage by stage, with the equations. If you want to check the standard at equation level, start there.
The reference covers the standard, and for anything beyond it, ask the people who built it.