FAQs on LED technology

1. What are the benefits of LED compared to conventional luminaire lighting?

  • Longer service life. This increases the maintenance-free operating period.
  • High-performance diodes provide excellent luminous efficacy.
  • LEDs are incredibly energy efficient.
  • Operating and maintenance costs are reduced to a minimum.
  • Lower CO2 emissions – this means that using LED lamps helps reduce climate change.
  • Ideal for use in extreme temperatures.
  • LEDs are set apart from other lights due to their high vibration resistance. This makes them especially suitable for use in harsh industrial environments.
  • LED lamps improve safety, because they lose their luminosity gradually and do not fail suddenly.
  • The luminous intensity can be adjusted in accordance to the varying ambient.

2. What are the disadvantages of LED?

LEDs are initially expensive in terms of procurement costs, but ultimately the cost benefits of using modern LED technology far outstrip this in the long-term. These benefits can be easily established via our TCO-/ ROI calculator.

3. Should we wait a little longer before using LED?

No. LED technology is the most cost-effective and the most up-to-date lighting technology in the market. When you switch as early as possible, the long operating life ensures great cost benefits. Quick decisions will save you maintenance costs as well.

4. How advanced is the development of LED?

The use of LEDs is no longer a topic of the future. The technology is now sophisticated enough that it can be used without restrictions. The luminous efficacy is significantly over 100 lm/W.

5. What is the service life of LED?

LEDs, in comparison to traditional luminaire lighting, do not need to be replaced as regularly. With more than 100,000 hours service life, LEDs can continuously operate for over 10 years.

6. Why are LED luminaires more expensive compared to conventional luminaires?

The manufacturing of LEDs involves durable, high-quality materials that are impact and thermal active. Their production is also accompanied by higher manufacturing costs, which makes them more expensive than conventional luminaires, but this only applies to the procurement price. The slightly higher procurement costs will be quickly compensated by lower operating costs thanks to electricity savings and lower maintenance costs. Therefore, if we take into account the entire service life, LEDs are more cost-effective.

7. Do LED luminaires cause damage to the eyes?

No. All LED luminaires are subject to the EU Directive 2006/25/EC and are tested in accordance with EN 62471. This inspection must be confirmed with the EU declaration of conformity. When using LED luminaires which meet these criteria, there is no risk of eye damage.

8. Are the media reports of damage to eyes from blue light true?

This statement is not correct. When using LED luminaires which meet the criteria of EN 62471, there is no increased risk of eye damage caused by the blue light portion in the radiated spectrum of LED luminaires.

9. What effects does LED lighting have on light emissions and does this harm the environment?

R. STAHL's luminaires are developed in line with the guidelines issued by the IDA (International Dark Sky Association). This means that their radiation angles are configured such that no light is emitted towards the upper hemisphere, thus preventing light pollution. In line with EN 12464, the light is only emitted in the directions in which it is needed in order to fulfil the user's lighting requirements.

R. STAHL also produces luminaires that block shortwave radiation (specifically UV and blue light), as this kind of radiation has a tendency to attract insects. Ongoing investigations into the possible harmful effects of light on animals are a major focus at
R. STAHL, and the findings of these investigations are incorporated into the design of our luminaires.

10. What is the difference between LED and incandescent lamps?

The main difference lies in the luminous efficacy of the two light sources. With an efficacy of up to 180 lm/W, the LED is almost 10 times as efficient as a normal halogen lamp. Instead of converting 5% of the input energy to light, the LED converts up to 35% of the energy into visible radiation.

11. What is the difference between LED and gas discharge lamps?

Every high-pressure discharge lamp uses environmentally damaging mercury to generate visible light. The new LED technology does not require this highly polluting element.

12. What is the normal lifetime of LED?

LEDs have a service life of approximately 100,000 hours. That is the equivalent of over 10 years' continuous operation. However, the LED does not instantly fail at the end of this time. Instead, it will start to dim, dropping to no less than 70% of its original luminosity.

13. Will the light quality be comparable if we switch over to LED?

The quality of the light produced by LED is equal to, and generally better than that of conventional light sources.

14. Are LEDs as bright as conventional lamps?

Yes, the brightness of LEDs is comparable to that of conventional lamps. With a lower nominal luminous flux, LEDs can produce illumination on par with conventional lamps, since the light they emit is directed exactly where it is required.

15. Can the brightness of LED be dimmed?

Yes. The brightness can be adjusted to cater to individual requirements and controlled using advanced light management systems. This makes LEDs a more efficient choice.

16. Does dimming LEDs reduce their service life?

No. The reduced power consumption may even extend their service life.

17. How long does it take LED lamps to light up?

LED lamps achieve full brightness as soon as they are switched on.

18. What are the key characteristics of LED light?

  • Luminous Flux (in Lumens)
  • Luminous intensity (in candela)
  • Illumination (in Lux)
  • Colour temperature/ CCT (in Kelvin)
  • Color Rendering Index/ CRI (no unit)

19. How is luminous intensity defined?

The luminous intensity (measured in candela) indicates the light a luminaire emits in dedicated directions. Unlike conventional lamps, LEDs emit light in only one direction. This means that LEDs can emit the required illuminance with a lower luminous flux, since they are not wasting energy by emitting light in directions other than where it is needed.

20. How is illumination defined?

The illumination (measured in lux) is a measure of how many lumens from a light source affect a particular surface.

21. How is the colour temperature defined?

The colour temperature (measured in kelvins) is the body temperature of a thermal radiator (incandescent lamp). The lower the value (e.g. 2,800 K), the warmer the light appears (yellowish). The light appears colder (bluish) at higher values (e.g. 6,500 K).

22. How is the power defined?

The electrical power (measured in watts) tells you how much energy the lamp consumes, but gives no indication of the lamp's luminous flux. Energy-efficient lighting must aim to generate as much light as possible whilst consuming as little power as possible – that is to say, to emit a large number/quantity of lumens per watt.