Double and triple glazed windows in Brussels, Flanders and Wallonia

PVC, aluminium or timber?

PVC is the most affordable choice: it insulates well, needs little maintenance and comes in many colours. Aluminium allows slim profiles and large glazed openings; it must include a thermal break to insulate properly. Timber gives a warm look and suits period homes, but needs regular maintenance.

Timber-aluminium composite frames combine the look of timber inside with the durability of aluminium outside, for a higher budget. In some Brussels neighbourhoods and protected areas, the material and the window divisions may be imposed by planning rules. The adviser checks these constraints with you upfront.

Double or triple glazing?

High-performance double glazing generally has a Ug-value of 1.0 to 1.1 W/m²K, compared with around 0.5 to 0.7 W/m²K for triple glazing. For the complete window, grants often require a Uw of 1.5 W/m²K or less and a Ug of 1.1 W/m²K or less.

Triple glazing is heavier and more expensive, but it is justified in an already well-insulated house, for large north-facing glazed areas or for better sound insulation. In a house that is still poorly insulated, good double glazing is often the most balanced choice. The adviser helps you decide.

Fitting, ventilation and grants

The quality of the fitting matters as much as the window itself: a poorly sealed junction with the masonry creates leaks and thermal bridges. As new windows are much more airtight, trickle vents are recommended to renew the air and prevent condensation. The quote should specify this.

Grants for windows depend on the region and your income, and may require a prior energy audit. Your RhinoEnergy adviser checks these conditions and calculates the support with you before you sign a quote. That way you avoid losing a grant through a simple administrative oversight or non-compliant glazing.