From June to September 2017, I was doing an internship at LEST. We were three French students from Polytech Nantes, and the aim of our traineeship was to model numerically (using Matlab) different houses and apartments. The man idea of our research was to set up a heating system to keep indoor temperatures on a comfort level (between 18 and 21°C). The LEST team was really nice and helpful, they were always ready to listen our questions, gave suggestions and help us to solve different issues. From a cultural point of view, even if we didn’t leave the European Union, we were able to discover a new culture in a country which is geographically located to give perfect opportunities to visit south Europe. Regarding this, advises from LEST team gave us the possibility to see best places in Ljubljana, Slovenia and its neighboring countries. To sum up, my internship at the LEST was really great experience, on personal and professional level, and I am looking forward to something similar in upcoming future.