Most of us notice the light only by its absence. Light is, by its definition, electromagnetic radiation visible by human eye, which is light containing wavelengths in the range of 380 to 780 nanometres [nm]. The main source of light is Sun, but as luminosity, that is- the intensity of light, changes not only on an annual basis but even on a daily basis, that way increases the need for artifical light. [1] In the begining, more precisely, 400 000 years ago, it was mostly fire. Fire was very useful because it has been used as substitution for sunlight, but even more important- it has been the source of heat and also animal protection. Thanks to the fire, numerous cave drawings were created, places where sunlight never reached like Altamira3 cave. The electrical lighting as we know it nowadays, has developed in 19th century, in 1879, more precisely, when Thomas Alva Edison invented incandescent bulb using schemes by german watchmaker Johann Heinrich Goebel. [2] That was the time when started the development of artificial lighting as we know it today which would be more thoroughly seen into in this thesis with the example of replacement of existing lighting with more efficient and popular LED4 lighting.