As a member of the board of the Klimaschutz-Unternehmen e.V. association, Mettler took up the issue of sustainability years ago and has been involved in many initiatives. With his invention of the Energy Scouts training project, which is now known beyond national borders, he has now been honoured with an honorary certificate from the Federal Minister of Economics and Climate Protection Robert Harbeck and DIHK President Peter Adrian in Berlin.

According to Mettler, raising young people's awareness of climate protection and energy efficiency has always been a matter close to his heart. At EBM-Papst, a group of young employees have been working for the benefit of environmental and climate protection since 2010, the 12th generation.