Insulation in Belgium: Complete Guide to Energy Solutions
Thermal insulation plays a key role in a building's energy performance. In Belgium, whether you're in Flanders, Brussels, or Wallonia, investing in good insulation not only reduces your energy bills but also contributes to a more sustainable environment. In this guide, we explain everything you need to know about insulation in Belgium, including available solutions, financial aid, and the key steps for a successful project.
Why insulate your home in Belgium?
1. Reduction of energy costs
A poorly insulated home can lead to significant heat loss, especially during Belgium's harsh winters. Proper insulation can reduce your energy consumption by up to 30%, resulting in significant savings on your heating bills.
2. Increased thermal comfort
Effective insulation ensures a constant temperature in your home, summer and winter. No more cold walls in winter and overheating in summer!
3. Environmental impact
By reducing your energy consumption, you also reduce your carbon footprint. This fits perfectly with European energy transition objectives.
The main areas to insulate in a house
To maximize your home's energy efficiency, here are the priority areas to insulate:
1. The roof
The roof is responsible for nearly 30% of heat loss. Insulating your roof (attic space or converted space) is therefore essential. The materials used include:
- Glass wool
- Rock wool
- Cellulose wadding
2. The walls
Exterior walls account for approximately 25% of heat loss. Insulation can be done from the inside (ETI) or from the outside (ETI). The most popular techniques include:
- Insulation with expanded polystyrene panels
- Insulating coating
- Wooden cladding with integrated insulation
3. The ground
The floor is often overlooked, but it can account for up to 10% of heat loss. Underfloor insulation (for example, with polyurethane or mineral wool) is recommended, especially if your home is built over a crawl space.
4. Windows
Windows are responsible for approximately 15% of heat loss. Replacing single glazing with double or triple glazing with enhanced insulation is an effective solution.
How much does insulation cost in Belgium?
The cost of insulation varies depending on several factors, including the area to be insulated, the type of material chosen, and the region where you live. Here is a guideline price list:
Note : These prices do not include financial aid or labor costs. For an accurate quote, contact a certified professional.
Key steps for a successful insulation project
- Energy diagnosis
Before you begin, conduct an energy audit of your home. This will help you identify priority areas for insulation. Choice of materials
Choose materials that fit your budget, your home, and your eco-friendly needs.Selecting a professional
Choose a certified contractor (e.g.: PEB approved in Wallonia or recognized by the Flemish Energy Agency in Flanders).Application for financial aid
Before starting work, check available grants and complete the necessary forms.Monitoring of work
Make sure that the work complies with current standards and that the insulation is correctly installed.
Insulation standards in Belgium in 2025
Thermal insulation standards were tightened in 2025, with specific requirements applicable throughout the country, both for new constructions and renovations:
Windows and frames : The maximum permitted U-value for the frame and glazing assembly is 1.5 W/m².K. For glazing alone, the thermal performance must be 1.1 W/m².K or less. These standards aim to effectively limit heat loss and encourage the installation of high-performance double or triple glazing 1 .
Exterior doors : They must also meet high insulation standards, similar to those of windows, with insulating materials and a design that guarantees low thermal conductivity 1 .
Applicability : These requirements apply to all buildings, new or renovated, and are essential to obtain a compliant PEB certificate 1 2 .
Each region adapts these standards within the framework of the PEB (Energy Performance of Buildings) regulations, with specific requirements for heating, ventilation, cooling systems and the maintenance of installations 2 .
Government bonuses and aid by region
Wallonia
New 2025 scheme : A temporary support scheme has been in effect since February 14, 2025. The income ceilings for eligibility are set at €114,000 of reference income, with a deduction of €5,000 per dependent child 3 .
Amounts of insulation bonuses (2025) 4 :
Roof and attic : €50 to €100/m² (U coefficient ≤ 0.20 W/m²K)
Walls : €22 to €132/m² (U coefficient ≤ 0.24 W/m²K)
Floors : 15 to 90 €/m² (R ≥ 3.5 m²K/W)
Exterior joinery : €65 to €390/m² (Uw ≤ 1.5 W/m²K, Ug ≤ 1.1 W/m²K)
Specific bonuses :
Insulation of pipes and hot water tanks: €50 to €510
Ventilation (single-flow CMV): up to €4,200
Ventilation (double flow CMV): €1,700 to €10,200
Terms :
The work must comply with technical standards and be carried out by approved professionals.
The premiums cannot exceed 70% of the total cost of the work 4 .
Brussels-Capital
Situation 2025 : RENOLUTION bonuses are suspended in 2025, pending a decision by the new government. No bonus applications with an invoice dated 2025 can be submitted at this time. Invoices from 2024 remain eligible under certain conditions .
Technical conditions (for previous bonuses):
Ug glazing ≤ 1.2 W/m²K
Work carried out by a professional registered with the BCE
The building must be at least 10 years old
Procedure :
Request to be submitted after work, within 12 months following the balance invoice, with supporting documents 5 .
Flanders
2025 Bonuses : The My Building Bonus system remains active, with revised amounts for 2025 5 .
Terms :
Compliance with Flemish PEB regulations for insulation and technical installations.
Amounts and conditions vary depending on income and the nature of the work.
Amounts : The premiums cover the insulation of the roof, walls, floors, and the replacement of frames, with ceilings adapted to the income and composition of the household.
Comparative table of the main conditions and amounts (2025)
| Region | Insulation bonuses (examples) | Main technical conditions | Situation 2025 |
|---|---|---|---|
| Wallonia | Roof: €50-100/m² Walls: €22-132/m² Floors: 15-90 €/m² Frame: 65-390 €/m² | U roof ≤ 0.20 U walls ≤ 0.24 Uw chassis ≤ 1.5 Ug glazing ≤ 1.1 | New temporary regime in force |
| Brussels | Suspended bonuses (2025) | Ug glazing ≤ 1.2 Building ≥ 10 years old Certified professional | RENOLUTION bonuses suspended |
| Flanders | Mijn VerbouwPremie (revised amounts) | Compliance with Flemish PEB Amounts according to income | Active bonuses, adjusted amounts |
Key takeaways
Insulation standards are being strengthened across Belgium by 2025, with strict U-values for windows, doors and glazing .
Bonuses in Wallonia are maintained and adapted with a new temporary system, capped according to income and type of work 3 4 .
In Brussels, bonuses are suspended for 2025 pending new government decisions .
In Flanders, the Mijn VerbouwPremie system remains in place with amounts adjusted for 2025 .
FAQ: Frequently Asked Questions About Isolation
What is the lifespan of insulation?
The lifespan depends on the material used. For example, glass wool can last 30 to 50 years, while polystyrene panels have a similar lifespan.
Can I insulate my house myself?
Some simple tasks (e.g., installing fiberglass in lost joists) can be handled by an experienced DIYer. However, for complex jobs like exterior wall insulation, it is recommended to call in a professional.
When is the best time to isolate?
The ideal is to carry out the work during the less cold months (spring or autumn), but this depends mainly on the availability of the contractors.
Conclusion
Thermal insulation is a profitable long-term investment, both financially and environmentally. In Belgium, financial aid and grants make this work even more accessible. Whether you live in Flanders, Brussels, or Wallonia, don't hesitate to contact regional organizations to take advantage of available subsidies.