Every area page on this site is generated from the same national data CrierData's search tool runs on — not written by hand, and not estimated. This page explains where the numbers come from, how often they change, and a couple of honest limits worth knowing about.
Every figure is a real count from a national register, matched to individual properties by their UPRN — the unique property reference number every address in Great Britain is assigned. Nothing here is modelled or estimated to fill a gap; where a register doesn't cover something, the page says so rather than guessing.
The government's EPC register refreshes roughly once a month. Each time it does, we rebuild every figure on this site from that snapshot — the "data as of" date in the footer of every page tells you exactly which one. Between rebuilds, the numbers don't drift or update live; they're fixed to that release.
A small number of wards and postcode districts have too few matched properties to publish on their own page — under 10, the same threshold used across official small-area statistics to avoid drawing conclusions from a handful of homes. Their properties aren't excluded or hidden: they're still counted in their local authority's totals, just not broken out as an individual page.
Postcode districts are Royal Mail's own geography, not local government's, and the two don't always agree — a single postcode district can genuinely straddle two or three council areas. Where that happens, this site shows the real split rather than picking one council to credit the whole district to.