Insulation prices in Belgium in 2026
Clear ranges by zone (roof, walls/facade, floor), what makes the bill vary and the grants that take back up to 50% of it. Enough to estimate your insulation project before you even request a quote.
Indicative ranges, grants not deducted.
Insulation prices by zone and surface area
Ranges for insulation supplied and installed, including labour, fixings and standard finishing. The thicknesses meet the R-values required for the grants.
| Zone | Small surface ≈ 50 m² | Medium surface ≈ 100 m² | Large surface ≈ 150 m² |
|---|---|---|---|
| RoofUnconverted or converted loft | 1 000 – 2 500 € | 2 000 – 5 000 € | 3 000 – 7 500 € |
| Walls / facadeExternal, internal or injection | 4 000 – 8 000 € | 8 000 – 16 000 € | 12 000 – 24 000 € |
| FloorConcrete slab or timber floor | 1 250 – 2 500 € | 2 500 – 5 000 € | 3 750 – 7 500 € |
Indicative prices incl. VAT, installation and finishing included, grants not deducted. The exact configuration (insulant, thickness, technique) is priced during the free quote. Detail by zone: roof, walls, floor.
What makes the price of your insulation vary
For the same surface area, two quotes can differ significantly. Here are the items that really weigh on the bill.
- Zone insulated
The roof, the walls or the floor involve neither the same materials nor the same labour. The roof remains the most cost-effective item to prioritise.
Insulation guide → - Type of insulant
PUR, PIR, rock wool, glass wool, cellulose wadding or cork: each material has its own cost and performance. Blown wadding in an unconverted loft is often the most economical.
- Required thickness
The higher the target R-value, the more the thickness (and the cost) increases. The grant thresholds set minimums: R ≥ 4,5 for the roof in Wallonia, for example.
- Installation technique
External insulation (ETICS), internal insulation or cavity-wall injection: external insulation is more effective but more costly; injection is fast and minimally invasive.
Which insulant to choose? → - Finishes & claddings
After external insulation, a render, timber cladding or facing requires additional finishing. Inside, reinstating plaster and joinery adds to the quote.
- Site access
Scaffolding on a high facade, a steeply pitched roof or a hard-to-reach basement lengthen the installation time and increase the bill.
The grants that ease the cost of your insulation
Insulating your home entitles you to regional grants and to reduced 6% VAT. Here are the 2026 benchmarks — we calculate the amounts and put together the files for you.
Prime Habitation insulation
Grant for upgrading thermal insulation, calculated by zone (roof, walls, floor) and by income category. Low-income households benefit from multiplier coefficients.
- Minimum thermal resistance reached by zone (R ≥ 4,5 roof, R ≥ 3,5 walls)
- Registered contractor and itemised invoice with R-values
- Prior housing audit recommended to maximise the amounts
Renolution — insulation
As part of the Renolution programme, Brussels Environment subsidises the insulation of the roof, walls and floor with three income categories that raise the grant amount.
- Minimum R-value compliant with the Renolution requirement per element
- Home over 10 years old
- Application submitted within deadline after the final invoice
Receive your price net of grants, in 48h
We check your entitlements, price net of grant and put together the file: you advance nothing.
- We check your entitlements
Region, income, age of the home: we identify every grant you can claim for each insulated zone.
- We price net of grant
The quote shows the estimated grant amount and the 6% VAT applied, zone by zone.
- We put together the file
Forms, technical certificates, compliant invoices: we handle it entirely.
- We deduct where possible
The grant is subtracted from your invoice with no cash advance, or paid directly after the works.
Based in Flanders? The Mijn VerbouwPremie also covers insulation — ask us for the detail for your municipality.
A range in 10 seconds
Choose the zone to insulate and enter the surface area for a ballpark figure. The free quote remains the only precise estimate.
Indicative estimate, excluding options and specific configuration.
What a real quote looks like
A concrete case to bring the ranges to life — your project will be priced according to your surface areas and your home.
Indicative example dated 2026, excluding options (specific vapour barrier, timber cladding, floor insulation). Request your quote for pricing tailored to your surface areas.
Dig deeper before deciding
- Insulation guide The whole silo
Materials, installation techniques, R-values and synergies with other energy works.
See the full guide → - Which insulant to choose? Technical guide
PUR, PIR, wool, cellulose: compare the performance, costs and environmental labels.
Compare insulants → - Insulation grants By region
The grant detail for Wallonia, Brussels and Flanders: amounts, conditions and procedures.
Explore the subsidies →
Your questions about insulation prices
How much does roof insulation cost in 2026?
For a blown, unconverted loft, expect 20 to 35 €/m² installed. For a converted loft (between rafters), the range rises to 35–50 €/m². It is the most cost-effective item: the return on investment is often under 5 years after grants.
Is external insulation (ETICS) more expensive than internal insulation?
Yes. External insulation generally costs 80 to 160 €/m² (insulant + render or cladding + scaffolding) versus 40 to 90 €/m² for internal insulation. But external insulation does not reduce the living space, eliminates slab thermal bridges and is often eligible for a higher grant.
Do grants really cover half the cost?
For low-income households in Wallonia or Brussels, grants can indeed reach 40 to 50% of the works amount, sometimes more on the roof. For median incomes, expect rather 20 to 30%. We calculate the exact amount during the quote.
Do I need an energy auditor before the works?
In Wallonia, a prior housing audit is mandatory for certain grant categories and optimises the amounts. In Brussels, it is strongly recommended to benefit from the full Renolution programme. We guide this step and work with accredited auditors.
Does the quote include the scaffolding and the finishing?
Yes. Our quote details each item: supply of the insulant, installation, scaffolding, finishing (render, skirting, disposal). There are no surprises during the works.
Can you insulate roof, walls and floor at the same time?
Yes, and it is often the most economical strategy: travel, scaffolding and finishing are shared, and the grants can be combined per element. A global project reduces the marginal cost of each additional zone accordingly.
Your exact price, costed and net of grants
The ranges give the ballpark — the quote gives the figure. Free on-site survey, grants calculated, a single point of contact. In under a minute.
- Free and with no commitment
- Grants & 6% VAT calculated and deducted
- Priced quote within 48 working hours