What does cavity wall insulation cost in Belgium in 2026?
Last updated: April 2026
Cavity wall insulation is one of the quickest and most cost-effective ways to make your home more sustainable and reduce energy costs. This cost guide gives a clear overview of typical 2026 prices, the main cost components, and the choices that influence the final price.
The price ranges are between €1,500 and €2,400 per project, based on up to date 2026 market data. The wall surface area and chosen insulation material determine the final price.
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This is an estimate based on average 2026 prices. Actual costs may vary. Always request multiple quotes for an exact price.
Cost factors
The total cost usually consists of:
- Insulation materials: 40-55% of the total
- Labor: 25-35% of the total
- Inspection and preparation: 10-15% of the total
- Access and finishing: 5-10% of the total
These percentages can vary depending on the situation and materials chosen.
Why do prices vary?
- Cavity width: A wider cavity offers more material options.
- Facade type: Some facades require extra preparation.
- Material choice: Insulation materials vary in price and performance.
- Accessibility: Height and access can increase the cost.
Subsidies & incentives
Cavity wall insulation qualifies for regional renovation grants. With this subsidy, you can significantly reduce insulation costs and achieve faster payback through lower energy bills.
regional grants Subsidy for Cavity Wall Insulation
The subsidy amounts to:
- Standard rate: €5.25 per m²
- When combined with other insulation measure: €10.50 per m² (doubling rule)
- Biobased bonus: €1.50 per m² extra when using biobased insulation material
Requirements
- Minimum surface: 10 m²
- Maximum surface: 170 m²
- Minimum Rd-value: 1.1 m²K/W
Example Calculations
- Scenario 1: Cavity wall insulation only (80 m²)80 m² × €5.25 = €420 subsidy
- Scenario 2: Cavity wall + roof insulation (80 m²)80 m² × €10.50 = €840 subsidy (due to doubling rule)
- Scenario 3: Cavity wall + other measure + biobased material (80 m²)Base subsidy: 80 m² × €10.50 = €840Biobased bonus: 80 m² × €1.50 = €120Total: €960 subsidy
Doubling Rule
The subsidy amount doubles when you combine cavity wall insulation with at least one other regional grants-eligible measure, such as:
- Roof insulation
- Floor insulation
- Facade insulation
- Heat pump
Regional price differences
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