EgoKiefer vinyl windows XL® with cold-blocker: vinyl windows do reach their limits in today’s modern architecture with its large-sized windows elements. That’s why modern windows are reinforced with steel elements. Steel has a disadvantage – it is a good heat conductor. This contrasts the high thermal insulation requirements. EgoKiefer developed an alternative technology for its XL® cold-blocking window. The fibreglass reinforced plastics give the optimal rigidity to the vinyl profiles and allows also a reduction of the heat-transfer rate. This is how modern architecture does harmonize with high heat insulation and tightened energy policies.