82 mm profile depth with six chambers reaches Uw values down to 0.67 W/m²K — enough for passive-house certification when combined with the right triple glazing.
The passive-house standard requires annual heating energy below 15 kWh/m² and total primary energy under 120 kWh/m². These numbers look ambitious, but they're achieved first and foremost through envelope quality — and joinery is one of the critical components.
The VEKA Softline 82 profile system was developed with exactly this in mind. Six chambers within 82 mm depth, triple sealing (or central sealing for the MD variant) and steel reinforcement in both sash and frame form the foundation. Combined with triple insulating glass at Ug = 0.4 W/m²K and a Swisspacer V warm-edge spacer, the total Uw drops to 0.67 W/m²K.
It's important to understand that the profile's Uf value is only half the story. Thermal bridges also form at the joint between the joinery and the wall — proper RAL installation (three sealing planes: inner vapour barrier, middle insulation, outer weather-resistant layer) is often what separates a certified building from one that fails the blower-door air-tightness test.
On every passive-house project we visit the site before installing joinery, agree the installation approach with the supervising engineer and deliver the RAL-installation materials together with the windows. This ensures that the value invested in the profile system isn't undermined by poor installation.
