We also choose to drive a low electric current (forward current) through the LEDs in most cases, thereby further improving efficiency. We select optical components like lenses and diffusors made from low-loss materials. Thus, the total system efficiency (the ratio between light emanating from the fixture and power drawn from the line) is optimal.

LED lighting is more suitable for this than fluorescents. LED can be switched on and off without limit and is eminently dimmable. Where users are present in the surroundings, dimming may be preferred to switching off: it has a safer, less deserted feel to it.

Modern systems are often dimmed digitally in accordance with the DALI protocol (Digital Addressable Lighting Interface). Each lamp has its own 6-bit address in the (sub)network. For instance, DALI command 125 6 dims lamp number 62 to its lowest possible level. Groups can be defined: command 138 246 dims all lamps of group 5 to 80% of their capacity. Moreover, 'scenes' can be set for various situations. A daytime scene could entail lamps near windows being off and other lamps somewhat dimmed. Command 255 31 turns every lamp to its light level for scene 15. A benefit of DALI control is the option to query remotely whether lamps still work. To control the lighting, we use movement, daylight and occupancy sensors. Which sensor is suitable depends on the situation and the application. The sensors can be connected to a digital dimming network according to the DALI protocol or with a central building automation system, for instance using the KNX protocol.