One framework, three transpositions
The European directive on the energy performance of buildings, in its 2024 revision, sets an objective of carbon neutrality for the building stock by 2050. It binds all three regions.
Beyond that shared objective, everything differs. Thresholds, vocabulary and timetable are specific to each region.
| Region | Certification | New build standard |
|---|---|---|
| Wallonia | PEB | Q-ZEN since 1 January 2021 |
| Flanders | EPB | own indicators and thresholds |
| Brussels-Capital | PEB | own indicators and thresholds |
The acronyms themselves are a trap. PEB in Wallonia and Brussels, EPB in Flanders, do not denote identical calculation methods. A level achieved in one region does not translate mechanically into another.
Wallonia tightens its requirements in 2026
A recent development bears directly on the cost of new build. It concerns the standard applying in Wallonia since 2021.
Since 1 January 2021, buildings to be constructed must meet the Q-ZEN standard, that is near-zero consumption, with a high level of insulation, controlled airtightness and use of renewable energy. That standard is checked on the regional energy portal before any costing.
Since 1 January 2026 a further requirement applies: new and equivalent buildings must incorporate at least 35 % renewable energy in their annual primary energy consumption. For buildings whose total useful area reaches or exceeds 1,000 m², that percentage must include at least 15 % from systems using energy produced from renewable sources.
This requirement has a direct budget effect: it drives equipment decisions from design stage and cannot be made good at the end of a project. Equipment decisions are therefore fixed from the sketch stage.
For refurbishment, the Walloon requirements applicable since 2017 remain unchanged.
The major renovation threshold
A feature common to all three regions, with modalities specific to each. It is the threshold for major refurbishment.
Where a refurbishment exceeds a given percentage of the building envelope, it moves into a regime of enhanced requirements, close to new build on several points, notably on ventilation. The exact percentage and the applicable requirements vary by region.
That threshold acts as a budget cliff. A project slightly below it and one slightly above do not cost the same, although their briefs are nearly identical.
Checking which side of the threshold a project falls on is therefore an estimating step in its own right, and sometimes a decision lever. Staying below the threshold can change the whole economics of a scheme.
Existing stock is becoming a cost factor
This is the most important development of recent years, and it changes the nature of the subject. The obligations now bear on the existing stock.
All three regions are introducing mechanisms placing obligations on existing buildings, and no longer only on new construction. Their scope and timetable are checked region by region.
In Flanders, a renovation obligation applies after acquiring an insufficiently performing property, within a set period.
In Wallonia, the timetable was entirely recast in December 2025, the previous plan having been judged unrealistic by the industry. The new framework targets the disappearance of the poorest labels and provides for works obligations linked to transactions.
In Brussels, a regional renovation strategy likewise frames the trajectory of the stock.
One indirect mechanism deserves mention for its immediate financial effect: in Wallonia the label governs rent indexation, the poorest-performing dwellings no longer being able to benefit from it. The label thus becomes an economic variable and not only a technical one.
The Walloon timetable is presented divergently across sources, both on commencement dates and on required levels. Verification with the regional administration is indispensable before any commitment.
What this changes for cost
Four concrete effects.
The cost of compliance is regional. The same brief does not carry the same minimum cost across regions, independently of any quality decision.
The obligation cannot be retrofitted cheaply. Energy requirements are settled at design stage, through envelope, orientation and equipment. Late correction costs disproportionately.
Acquiring an existing property carries a programmed charge. The compliance budget belongs in the funding plan, not in later projects.
Use value depends on the label. Rent indexation, access to support and resale value depend on it, which shifts the trade-off between refurbishing and doing nothing.
What this means for an estimate
Three rules.
Name the region before pricing performance. No level, indicator or threshold transfers between regions.
Check the position relative to major renovation thresholds, which can change the applicable regime.
Date every requirement cited. This field changes several times within a legislature, and a requirement read a year ago may have been tightened.
This article reflects regulation at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.