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LED ceiling lights - a selection aid understandable for everyone

In the past, downlights were available as halogen recessed spots or with larger recessed ceiling lights using incandescent or energy-saving lamps. Either reflectors, which required a correspondingly large installation depth, or diffuse panes ensured homogeneous light emission. The range of possibilities was limited.
With the introduction of LED, the selection has become unmanageable for the user. The following overview should help you find the right LED downlights for your application.

The ceiling cutout or hole diameter of LED ceiling spotlights

Especially when changing from conventional recessed ceiling lights to LED downlights, the question of this rarely arises. The hole already exists and accordingly this is more of a limitation with existing buildings. As a search aid, we have set up a filter with which it is possible to limit the number of products displayed in the first step. We offer LED recessed lights for hole diameters from 35 mm to 230 mm.
But be careful, in many cases the ballast must also fit through the hole. Corresponding information on the dimensions can be found in the data sheets and tables.
When it comes to new building planning, all possibilities are open with regard to the hole diameter and the holes are then drilled according to other lighting criteria.
The maximum installation depth must also be observed.

Light output & lumen - how bright should it be?

With regard to conventional halogen spotlights, it was easy or you had experience. 20W, 35W or 50W and the number of ceiling spots was decided by the wallet or sometimes existing geometry.
With the use of LED recessed ceiling spotlights, it often makes more sense to use planning software such as Dialux or Relux to determine it. But not everyone has these options. Accordingly, we would like to offer a very pragmatic approach.
Wikipedia shows examples of illuminance. These show how brightly an area is illuminated. Would you like to illuminate a hallway or entrance area with e.g. 10 square meters with 100 lux, so theoretically it needs a luminous flux of 1000 lumens. (Lux means Lumen/qm). However, light distributes itself differently in the room and reflects on the walls, or is swallowed by dark walls and therefore a additional of 1.5 may be added here, which leads to a minimum luminous flux of all LED ceiling spotlights of 1500 lumens. For example, 4 pieces of Fabio 35 at 400 lux each. (for comparison, approx. 25W halogen)
Depending on the beam angle, these can be divided into the 10 square meters mentioned in this example.

Beam angle of LED ceiling recessed spots

Normally, the beam angle of a luminaire is half the highest lux value of the light beam (full half-width or 'Full Width at Half Maximum', FWHM). Usually there is a lot of scattered light outside the beam, which creates annoying glare. For this reason, the solution developed by Bartenbach also works with bundle degrees that are based on the level of the 10% lux value (half the full width at half maximum or 'Full Width at Tenth Maximum', FWTM). The Fabio 35 reflector lamp, for example, emits 2 x 18.9 ° at FWHM height and still only 2 x 32.7 ° at FWTM height. In comparison, a standard GU10 halogen lamp only emits at 2 x 12 °, but the beam angle at FWTM level is still much wider than that of the Fabio 35. This means that the standard light bulb creates much more glare than the reflector lamp. In short, the light from Illuxtron LED downlights is used more efficiently thanks to better optics and reflectors, as there is less scattered light and is more pleasant thanks to less glare.

According to the geometric laws (equilateral triangle with beam angle at the top), height also plays a role in the area of illumination. This can be easily calculated with simple math to find the best placement of the LED recessed lights.

Colour temperature / colour rendering index according to location

Most consumers are now aware of the differences in colour temperature and use terms such as "warm white", "neutral white" or "cold white". Unfortunately these data are only a rough classification. In the meantime, LED technology and Illuxtron LED downlights are now available for colour temperatures from 1800K to 5700K. Below is a small overview of the appropriate application.

Control and dimming of LED recessed ceiling spotlights

Area of application LED downlights
Colour temperature
Colour rendering index / CRI
General lighting, apartment, restaurants2700K - 3000K 80 - 90
Office lighting, workplaces4000K > 80
Clothing stores3000 - 4000K > 90
Meat and sausage counters1800 - 2200K > 85, R9 > 80
Bread and baked goods2200 - 2700K > 90

Further details regarding special sales requirements can be found in the LUXEON Stylist downlight series developed by Illuxtron.

Control and dimming of LED recessed ceiling spotlights

We offer the Illuxtron LED ceiling recessed spots according to the manufacturers suggestions. The first step should be to consider: dimming required, if yes - which technology for dimming should be used. Often only 3-wire installations exist in existing buildings, so that only phase dimmers can be used. Almost all Illuxtron recessed ceiling lights can alternatively be supplied with a suitable driver.
LED drivers with external control inputs for DALI, 1-10V or a simple push button offer a more convenient and better dimming experience. More about this at the LED drivers. For new installations, we favor the option of operating several LED downlights in series on one driver. In existing buildings, it depends on the existing installation. Should e.g. GU10 recessed ceiling spots be replaced, 230V mains voltage is already available on the ceiling cutouts.
As an alternative to converting 12V halogen with a central halogen transformer, you can now easily convert to 24V constant voltage operation with a central LED control gear. The respective possible options can be found in the selection menus.

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