What features cost · sale listings since January 2024

Anatomy of a price

Every premium is measured within cells of region, property class and construction era against a stated reference, then weighted by sample across cells, so geography and age are held still. Premiums are in price per square metre and describe associations in asking prices, not causes.

Premiums

The bill of a house

A Belgian house is described by its number of facades before anything else: two for a terraced house, three for a semi, four for a detached one. The chart prices that and every other feature the listings record, one row each, against a reference drawn hollow.

Two features are kept off the chart. An attic reads as on a house and a basement as on a house and on an apartment, but the listings never record an explicit no for either, so every blank is read as absent and the reference mixes homes without one with homes that did not say. The same reading applies to and , which is why indoor parking is marked read with care.

Double glazing is marked for the opposite reason: almost every listing says yes, so the reference is the houses and apartments that explicitly say no, a small and unusual group, and the premium says more about those homes than about the glazing.

Premiums are per square metre. A feature that comes with more floor space, such as a fourth facade or a garden, can raise the price of a home while lowering its price per square metre, which is why the facade table beside the chart carries absolute medians as well.

The receipt

Build a price

Choose a region, a type and a set of features, and the receipt applies each premium in turn to the median price per square metre of the reference home. It is an arithmetic of associations, itemised the way a notary itemises costs, and its total is an indication rather than a valuation.

Every premium is taken from Figure 3.1 for the chosen region; where the region has too few listings for a feature the national figure stands in and the line says so. The reference levels, good condition, gas heating and an installed kitchen, add no line, because they are the home the baseline describes.

By region

Where features matter most

The national premium hides three markets. The same feature is measured in each region separately, cells of class and era still held fixed, and the matrix prints the three figures side by side on a diverging fill.

prices features more strongly than on of the rows priced in both.

Brussels is the thin column. Its are fewer and its cells smaller, so a Brussels figure on a rare feature rests on a few dozen listings and moves with them; the hatched cells are the ones that fell under the floor of entirely.

A cell of region, class and construction era enters a premium only when both the feature level and its reference have at least listings in it; the regional figure weights the surviving cells by the level's count. The headline of Figure 3.1 considers only features with at least listings in each region, so a thin cell cannot set the record.

Only listings observed from enter, so price drift inside a cell is small.

A blank is not read the same way for every feature. For and the listings never record an explicit no, so a blank is read as absent and the reference includes homes that simply did not say; for every other feature a blank is unknown and the listing is left out of that comparison.