Planning to insulate your cavity walls in 2026? Discover the grants and financial support available in Flanders, Brussels and Wallonia.
Updated on 5 October 2026
Financial support for cavity wall insulation is not the same throughout Belgium. Flanders, Brussels and Wallonia each have their own system, and several important changes came into effect in 2026.
In this article, we explain the current situation for cavity wall insulation in each of Belgium's three regions.
Yes, financial support for cavity wall insulation may still be available in 2026. However, there is no single nationwide Belgian grant.
The rules depend on the region in which the property is located.
In Flanders, insulating an existing cavity wall falls under the external wall category of Mijn VerbouwPremie. Brussels has a different situation concerning RENOLUTION grants in 2026, while Wallonia introduced a new renovation support system on 1 October 2026.
It is therefore important to check the rules that apply to your region and personal situation at the time of application.
For applications submitted from 1 March 2026, owner-occupiers in income categories 3 and 4 can still qualify for Mijn VerbouwPremie under the external wall category.
For income category 3, the grant can cover up to 35% of the eligible invoice amount, with a maximum of €3,500 for the external wall category.
For income category 4, this can rise to 50%, with a maximum of €5,000.
Owner-occupiers in income categories 1 and 2 can no longer receive Mijn VerbouwPremie for this category for applications submitted from 1 March 2026.
Cavity wall insulation must also comply with a number of technical requirements. The cavity must, among other things, be sufficiently wide, be completely filled and the work must comply with the applicable technical requirements.
The situation is different in the Brussels-Capital Region.
For works with a final invoice dated in 2025 or 2026, it is currently not possible to submit a new RENOLUTION grant application.
Older RENOLUTION grant amounts should therefore not automatically be considered applicable to works carried out in 2026.
However, this does not necessarily mean that no financial support is available.
Depending on your situation, other options may be relevant, such as the ECORENO loan, municipal support schemes or other financial measures.
It is important to note that ECORENO is a financing solution rather than a renovation grant.
Wallonia's renovation support system changed significantly in 2026.
The temporary Primes Habitation 2025-2026 scheme ended on 30 September 2026.
Since 1 October 2026, Wallonia has operated a new renovation system centred around schemes including Rénopack and Rénoprêt.
Under the new system, support is no longer simply calculated as a separate grant per square metre of cavity wall insulation.
The overall renovation project, the property's energy performance and the intended improvement of its PEB rating play a much greater role.
A prior energy audit also forms part of the process.
If you are planning cavity wall insulation in Wallonia, it is therefore important to determine how the work fits into the property's wider renovation project.
Being eligible for financial support based on your income or region does not automatically mean that every cavity wall insulation project will qualify.
The property and the existing cavity must be technically suitable for retrofitting.
In Flanders, for example, specific requirements apply under Mijn VerbouwPremie.
The cavity must be completely filled, have a sufficient minimum width and the insulation material must comply with the applicable technical requirements.
The quality of the installation is also important. For certain Flemish grant applications, cavity wall insulation must be installed in accordance with the applicable STS 71-1 requirements and the necessary certificates must be provided.
Nu-Isoleren therefore checks whether an existing cavity wall is suitable for insulation before the work is carried out.
The application procedure depends on the region in which the property is located.
In Flanders, Mijn VerbouwPremie is generally applied for after the work has been completed through Mijn VerbouwLoket.
You will need the relevant invoices and the required contractor certificates. For cavity wall insulation, technical documents relating to the installation may also be required.
Brussels and Wallonia use different procedures and forms of support.
It is therefore advisable to determine before starting the work which system applies to your property and which documents you will need to keep.
For a complete overview, you can also visit our page about renovation and insulation grants in Belgium.
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