Considering that there are many products on the market, that look very similar and it is difficult for customers to choose which one is the best, we wanted to make a short guide for the most important parameters of lamps and fixtures.
Luminous efficiency – the ratio of luminous flux (lumen [lm]) of the specific light source to power (watts [W]), which is consumed during operation. It is the energy efficiency of a light source, the higher it is, the more light we get out of 1 watt. It does not take into account the quality of light, only its quantity.
The theoretical highest value of the luminous efficacy is 683 lm / W for the light of one color (monochrome) – in this case, it is a green light with an electromagnetic wave length of 555 nm.
We express luminous efficacy in Lumens / Wat – lm / W.
Exemplary light efficiency of common sources of light (together with the method of light generation):
Light-emitting diodes:
• White LED diode (electroluminescence) – 80 – 300 lm/W
Temperature sources:
• Traditional light bulb (incandescence) – 8 – 12 lm/W
• Halogen bulb (incandescence) – 12 – 16 lm/W
Fluorescent sources:
• linear fluorescent lamp (photoluminescence) – 45 – 100 lm/W
• Compact fluorescent lamp (photoluminescence) – 50 – 70 lm/W
• Induction Lamp (photoluminescence) – 60 – 90 lm/W
Discharge sources:
• The metal halide lamp (electroluminescence) – 65 – 115 lm/W
• The high-pressure sodium lamp (electroluminescence) – 85 – 150 lm/W
• The low-pressure sodium lamp (electroluminescence) – 100 – 200 lm/W
