This is the stable, versioned method behind ChatHome's commune price pages and monthly Price Index reports. It explains exactly what enters each figure—and what does not.
The index uses residential listings that are active and eligible for ChatHome's public catalogue at the time of computation. Disabled listings are terminal and never enter the calculation.
Listings are grouped by commune, sale or rent intent, and apartment or house type. Luxembourg City quarters are folded into the Luxembourg commune. Steinsel is currently excluded because its location data does not meet the publication standard.
For each segment, ChatHome divides the asking price by usable floor area, removes implausible residential values, then reports the median €/m². Sale values outside €500–€40,000/m² and rent values outside €3–€120/m² per month are excluded as likely data errors or non-comparable property types.
The national headline is the unweighted median of publishable commune apartment-sale medians. It describes the covered communes; it is not a transaction-price index or a valuation of a specific home.
A precise median is published only when at least five listings support that commune, intent and property-type segment. Each proprietary median is shown with its segment sample size and computation date.
With two to four observations, a commune page may show the 25th–75th percentile range instead of a precise median. A single observation is not published as a price statistic.
ChatHome asking prices and official transaction-based figures are kept separate. STATEC and Observatoire de l'Habitat figures may be displayed for context and quarterly direction, with their source period attached; they do not overwrite the live-listing median.
Each Price Index page carries a real computation date. This methodology receives a new version only when an inclusion rule, threshold, estimator or source treatment changes. A data refresh alone does not change the method version.
Asking prices can differ from completed sale or signed rent prices. Coverage reflects the active listings ChatHome can verify, not every property marketed in Luxembourg. Commune medians can also hide differences in size, condition, energy performance and micro-location.
Use the index as a transparent market benchmark, not as an appraisal, investment promise or substitute for professional legal, tax or valuation advice.