Lumilos is a work investigating the possibilities to use light and color in an interactive design context. I have explored different light sources and compared them to each other and given a short description of the history of light and how it has been developed during the industrialization in the western world. I have also investigated what is currently done in the field and summarized that with examples in the categories passive-, colored-, material- and interactive light. The conclusion is that working with interactive color and light is a hard task. There are many different angles to take into account such as personal likings and earlier experiences that is uncontrollable by the designer. Yet there are many possibilities and light is a material that is moldable in many forms. I have put the knowledge about light and color into practice and developed an interactive light wall that is visualizing energy consumption with the use of different colors of light and animations. The wall is built using modules to enable it to be scaled up and down to fit different contexts.