The home energy audit is mandatory in Wallonia to unlock the Primes Habitation — with one exception, roof and attic insulation, exempt since 14 February 2025. It typically costs €800 to €1,200 including VAT, is itself subsidised (€76 base, so €152 to €456 depending on income) and remains valid for 8 years. In Flanders and Brussels no audit is imposed for grants: the EPC certificate plays that role.
What a home energy audit really is
Do not confuse it with the EPC certificate. The certificate records performance at a point in time and is used for a sale or a rental. The audit prescribes: it analyses the building item by item and produces an ordered package of works, with priorities, estimated gains and costings.
In practice the accredited auditor visits, surveys the building envelope, surfaces, heating and ventilation systems, then issues a report registered with the administration. That report becomes the reference for the grant file: subsidised works must appear in it and be carried out in the recommended order.
Wallonia: the document that unlocks everything
This is the only place in the country where the audit is a condition of access to grants. Without a registered audit report predating the invoice, there is no Prime Habitation — however well the works were carried out.
⚠️ The mistake that costs you the grant. The audit must precede the works, and the invoice must be dated after the report. Ordering a heat pump and then having the audit done is irreversible: the file is rejected. It is by far the most common reason for refusal, and there is no appeal.
The audit is itself subsidised. The base amount is €76, multiplied by the coefficient of your income category:
| Category | Reference income | Coefficient | Audit grant |
|---|---|---|---|
| R1 | ≤ €28,900 | × 6 | €456 |
| R2 | €28,900 – €41,100 | × 4 | €304 |
| R3 | €41,100 – €54,300 | × 3 | €228 |
| R4 | €54,300 – €122,800 | × 2 | €152 |
For an audit invoiced between €800 and €1,200 including VAT, the net cost therefore falls to roughly €350 to €750 depending on income. The report stays valid for 8 years: it covers a renovation programme spread over several years, which puts the cost in perspective if you plan successive projects.
Since 14 February 2025, roof and attic insulation is the only item exempt from a prior audit. If your project is limited to the roof, you save both the cost of the audit and several weeks of lead time. That is one reason it is the best first job to launch in Wallonia.
The 30 September 2026 deadline
The current Primes Habitation scheme is a transitional regime running from 14 February 2025 to 30 September 2026. Every application — audit as well as works, final invoice included — must be submitted before that date.
The reform announced for what follows would move towards a systematic audit before and after the works, with support concentrated on renovations producing an EPC label jump. Since the final terms were not settled at the date of publication, prudence means wrapping up what can be wrapped up under the current scheme rather than betting on the next one.
Flanders and Brussels: no compulsory audit
In the other two regions no audit is required to access support. The logic differs: there the EPC certificate serves as the reference document, and it carries increasingly real obligations.
- Flanders: Mijn VerbouwPremie does not require an audit. The EPC, however, triggers the renovation obligation for the buyer of a property labelled E or F, who must reach label D within six years of the deed.
- Brussels: with Renolution grants suspended since 1 January 2025, the question of a prior audit no longer arises in practice. The EPC certificate, by contrast, now governs whether you may let the property.
That does not make an audit useless there — simply optional rather than compulsory. For a heavy renovation, having an ordered plan of works drawn up remains the best way to avoid expensive sequencing mistakes.
Choosing your auditor and reading the report
Verdict
In Wallonia, the audit is not a formality but the key to the file: without it, no grant, except for the roof. Given the grant on the audit itself and its 8-year validity, the real cost stays moderate for anyone planning several projects.
In Flanders and Brussels, it is a voluntary investment. It is justified for a heavy renovation or a property subject to a renovation obligation, much less so for a one-off job.