1980
 | Norbert Keller founded his first company in Schönberg in Belgium as a trained wrought iron smith. He made stairs and banisters and worked as a construction engineer. |
| He started selling steel and aluminium conservatories for other manufacturers. | 1983 |
1990
 | Norbert Keller AG was founded in Troisvierges, Luxembourg. |
| In other words only 2 years after the foundation of Keller AG, Norbert Keller himself became a manufacturer of conservatories. Together with 20 employees he created modern conservatories that were more in keeping with modern architecture and clients’ requirements. | 1992
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| 1993 | Profile systems with improved thermal separation were developed in-house, opening up new prospects in both home conservatory and building construction. |
| Keller AG started to build its European sales partner network. | 1996 |
2001
 | Together with his team, Norbert Keller developed a completely new home conservatory concept, KELLER Orangery Elegance, which was also presented in the next two years at the big construction exhibitions, Foire Internationale in Luxembourg, Batibouw in Brussels and Bau in Munich. This new development also signalled the start of KELLER AG’s international breakthrough. |
| Keller AG employed 70 staff and in recognition of his entrepreneurial achievements Norbert Keller was a finalist in the “Entrepreneur of the Year” competition in Luxembourg. | 2004 |
2007
 | Another high-tech development was launched, now familiar well beyond Europe’s borders under the name of KELLER minimal windows. This new, innovative frameless sliding window system once more set new standards in the home conservatory sector. |
| KELLER minimal windows was a finalist in the Products of High Architectural Quality category of the Architecture and Construction Innovation Award at Bau in Munich, the biggest construction exhibition in the world. This product was further developed and since 2012 it has been certified with the Low Energy Standard. | 2009
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| 2014 | Norbert Keller sold his 80% share of Keller AG to Luxemburger Capital Investment Group S.a.r.l. 20% of the shares were still owned by his then partner Jörg Heinemann. Since then he has taken on new challenges. So clients turn to him with confidence to seek expert advice on house buying, conversions, design and the development and implementation of their own individual living concept. |
