The unique technology by Luxmet saves electricity and burner fuel when operating an Electric Arc Furnace at a steel mill. With the help of Luxmet-control, the burners can be started 1,2…1,6 minutes earlier and stopped 2 minutes earlier than in a traditionally controlled EAF-process. The information has been verified during the Master Thesis made by Emilia Rontti in autumn 2019. In practice such numbers mean a significant cost efficiency improvement (easily 6-digit in €) and productivity increase. Luxmet technology is based on optical emission spectrum measurement.