How the valuation works
The valuation is an indicative figure derived from real local sales, not an estate-agent guess and not a paid AVM black box. Everything below is fully transparent.
1. Two datasets, joined
We work from two open datasets that cover England and Wales:
- HM Land Registry Price Paid Data — every residential sale recorded with the Land Registry from January 1995 to present, refreshed monthly.
- Domestic Energy Performance Certificates — every lodged EPC from 2012 to present, refreshed quarterly by the Department for Levelling Up, Housing and Communities.
We join the two on postcode + house number/name. The Land Registry doesn't record floor area, which is what we need for £/m² benchmarks. The EPC register does. About 84% of recent sales join cleanly.
2. Pulling the candidate pool
For a given address, we look up every Land Registry transaction in the same postcode outcode that completed in the last five years, capped at 2,000 candidates. Each candidate is joined to its EPC record (if available) for floor area + energy rating.
3. Composite scoring
Every candidate gets a composite score that mixes five signals. The weights are deliberately conservative:
| Signal | Logic | Weight |
|---|---|---|
| Recency | Exponential half-life of 2 years | 30% |
| Proximity | Same postcode > same outcode tier | 25% |
| Size match | Floor area within ±15% of target | 20% |
| Property type | Detached / semi / terrace / flat with adjacency rules | 15% |
| EPC band | Band match, with ±1 tier softening | 10% |
4. Estimated value
From the ten highest-scoring candidates, we take the medianprice-per-square-metre and multiply by the target's EPC floor area. The median is more robust than the mean against single high-end outliers.
What this is not
- A formal RICS valuation. Lenders need a Red Book valuation from a registered surveyor.
- A market-aware figure. We don't know if your kitchen was renovated last week or last decade.
- Sub-postcode granular. Pricing within a postcode can vary by ±15% based on plot, aspect, condition.
Treat the figure as a useful starting point for thinking, not the final answer.