A measurement of efficiency in a lighting installation is the installed output, in W/m², that is required to meet defined demands.
In addition to a low installed output, energy usage should be limited in an installation with the help of different control systems so the lighting can be adapted to requirements and used as efficiently as possible.
A better method of assessing the energy efficiency of a lighting system is to evaluate the annual energy consumption. This method is described in the EN 15193 standard, which is linked to the Energy Directive, see separate section. More precise calculations can also be performed in DIALux, or similar calculation programs. Here, you can take into account the reduction factors for control depending on presence/absence – light and constant light control.
The following points should be considered in order to create low energy usage in a lighting installation:
- Selection of light sources with optimal luminous efficacy for the required colour reproduction.
- Energy efficient lighting system with installed lighting output suitable for the required task.
- Efficient luminaires with the correct light distribution and good cut-off properties.
- Efficient utilisation of daylight.
- Efficient utilisation of artificial and natural light through the selection of a light interior colour scheme.
- Control of lighting through presence detection.
- Possibility of localised control by the individual.
- High frequency operation with dimming.
- Well planned maintenance of the lighting installation to obtain a high maintenance factor.
Installed lighting output
Required illuminance while operational (lx)
|Corridors||5–10 W/m²||100 lx|
|Corridors||10 W/m²||200 lx|
|General public areas||10–12 W/m²||300 lx|
|Workplaces||10–12 W/m²||300 lx||*)|
|Workplaces||10–15 W/m²||500 lx||*)|
|Workplaces||15–30 W/m²||1000 lx||*)|
|*) Required illuminance within the working zone according to EN 12464-1. The lower value normally presupposes a localised lighting system adapted to the working area in the workplace.|