Are you planning to carry out insulation work to optimise your home's thermal comfort? Opt for new insulation techniques and the most energy-efficient materials.

New insulation techniques: the most commonly used materials in Belgium

Properly insulating your home is vital to ensure optimal thermal comfort and reduced energy consumption.

In Belgium, new insulation techniques make use of materials such as polyurethane, aerogel, recycled glass, vacuum insulation and used fabrics.


Polyurethane is a synthetic material which is light, malleable and thin and has low thermal conductivity.           It’s one of the most widely used insulating materials in Belgium because it is an efficient, hard-wearing and very convenient insulator.

Polyurethane (PUR) insulation boards are very thin and weigh five times less than other insulation materials.
Not only are they easy to transport, they are also easy to install.
What’s more, there’s no longer any need to reinforce your roof structure before installation.

Polyurethane is generally used in insulation boards and foam insulation and is suitable for both interior and exterior insulation.
Polyurethane foam is mainly used in hard-to-reach areas.


Produced by nanotechnology, aerogel is a liquid material which is made up of 99.8% air.
What makes it so unique? It looks like a transparent gel but feels like polystyrene.

In terms of insulation, this material is known for its low thermal conductivity, lightness, flexibility and heat resistance. It can withstand temperatures of over 200°C and can stop all forms of heat transmission (convection, radiation, conduction).
Aerogel is both a good thermal and sound insulator.

Vacuum insulation

Vacuum insulation is renowned for its exceptional thermal conductivity.
Its thermal conductivity index is 8 times lower than that of glass wool. That’s why this material is one of the most effective on the market.

Vacuum insulation boards are made of amorphous silica powder which pressed into sheets, then wrapped in a polyester film and vacuum-packed. They are particularly suitable for interior insulation. In addition to their outstanding technical performance, they are also excellent acoustic insulators.

Used fabrics

Thermal insulation made from used fabrics (old clothes or recycled fabric scraps) is increasingly popular nowadays.
This is particularly true of cotton wool, which is both a good thermal and acoustic insulator.
Its main benefit? It is hygro-regulating, flexible and environmentally friendly.

Moreover, it’s an excellent thermal regulator.
That’s because cotton wool regulates humidity and stops thermal bridges while preventing the penetration of cold air in winter and hot air in summer.

Recycled glass

Insulation made from recycled glass is also widely used in Belgium, as is cellular glass. It’s made from recycled sand and glass debris, to which components such as iron oxide, sodium sulphate, manganese oxide, feldspar, sodium nitrate and carbon black are added.

Cellular glass insulation is an excellent thermal-acoustic insulator. It’s particularly hard-wearing and airtight; like polyurethane, it’s suitable for both interior and exterior insulation.

New insulation techniques: subsidies available in Belgium

If you didn’t know, subsidies can be provided for wall, floor and roof insulation in Belgium.
However, the conditions for these subsidies are different in Brussels and Wallonia.

Housing subsidies in Wallonia

In Wallonia, these subsidies are known as housing subsidies. Several requirements must be met:

  • Insulation work must be carried out by a contractor registered with the BCE (Banque-Carrefour des Entreprises)
  • Energy audits must be carried out to provide recommendations of possible grouped work
  • Audits must be completed by an approved auditor
  • Insulation co-efficient of at least 0.2W/m²K for the roof; 0.24W/m²K for the walls and 0.24W/m²K for the floor

Energy subsidies in Brussels

In Brussels, we talk about energy subsidies or, to be more precise, B subsidies (B1 for roof insulation, B2 for walls and B3 for the floor).

These are the key requirements:

  • Thermal resistance co-efficient of at least 0.4W/m²K for the roof; 0.35W/m²K for the walls if the work is done from the outside and 0.2W/m²K if it is done from the inside; and 0.2W/m²K for the floor if the work is done from above and 35W/m²K if it is done from below
  • Applications for subsidies can only be made once the work has been completed
  • Work must be carried out by a contractor registered with the BCE

It should be noted that the total amount of these subsidies depends on the applicant’s income and they are only valid for buildings to be renovated.