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Where entrepreneurship meets excellence

Group a is an international franchise organisation in the market of windows and doors and owner of two brands – Belisol and KwadrO - active in Belgium, the Netherlands and France

Group a is a Belgian family-owned company, founded in 1977 by Eugène Alen. We commercialise and offer a large range of quality windows and doors in PVC, aluminium and wood via a franchising network for our two brands, Belisol and KwadrO. Group a provides a complete concept based on market needs to service and delight the private customer.

Our brands

Group A, these are two strong brands in windows, doors and sliding windows.


Belisol is the market leader in Belgium and the Netherlands – and we do not take this responsibility lightly. Our aim is to provide our customers with a carefree installation or renovation of their external doors and windows – with a result they can be proud of.


KwadrO consists of a dynamic and entrepreneurial network of more than 20 showrooms all over Flanders, whose employees are passionate about the business.

Group a in numbers

Both Belisol and KwadrO are strong organizations with years of experience that prioritize the customer.

1000 employees

Divided across three countries, we have more than 1000 employees. Each of these individuals is a skilled expert in windows and doors.

65 years

Combined, Belisol and KwadrO have more than 65 years of experience. This enables us to have the necessary expertise within our industry

100 showrooms

With 100 showrooms spread across 3 countries, we have an extensive network to serve all of our customers.