When a client decides to replace a window or a door, the first things that come into his mind are:
• the prices. How expensive is the profile? • the brand name of the profile. What brand should I choose: Gealan, Rehau, Veka …? • how many chambers should the profile have etc… Should I choose 3 chambers profiles, 5 chambers or higher; • and the list could continue.
Of course these are important issues and there a many articles that gives criteria to differentiate them and what to choose. One aspect that should never be neglected is PVC profile class. According to European standard SR EN 12608 – Unplasticized polyvinylchloride (PVC-U) for the fabrication of windows and doors.
Classification, requirements and test methods – PVC profiles are divided into 3 classes according to:
• exterior wall thickness (practically the 2 sides of the profiles that you can see from inside and outside of the house); • interior wall thickness (practically the side of the profiles that “sits” on the building wall and the side that sustain the glass);
• A class - exterior wall thickness ≥ 2.8mm, interior wall thickness ≥ 2.5mm; • B class - exterior wall thickness ≥ 2.5mm, interior wall thickness ≥ 2mm; • C class – no requirements.
A profile can be part of a class if both conditions are respected simultaneously; otherwise the profile is suitable for immediate inferior class.
For example: a profile with exterior wall thickness of 2.9mm and interior wall thickness of 2.4mm can be classified as B class. You can ask the producer certificate from notified laboratory. A window made of A class profiles has a lower transfer coefficient then a window made of C class profiles, but its price will be higher.
To have a lower thermical transfer coefficient is better because heating loss is smaller. The higher price of the window can be compensated by energy savings. Competitive price can be obtained by having a balanced rapport between: profile class - montage depth – number of chambers.