LED lights really help with concentration

Finding LED lamps with the right light color and brightness

L.ED lamps use little electricity and have a long service life. The slightly higher selling price compared to halogen and energy-saving lamps quickly pays for itself. What the packaging information on lumens and light color mean and how you can find LEDs with pleasant light.

At first the trouble was huge when the old light bulbs were gradually thrown out of the market. The energy-saving lamps that were supposed to replace the old light sources were not accepted. The light was too cold, too uncomfortable. In addition, the unpopular fluorescent lamps contained dangerous mercury. The lamps are hazardous waste. If an energy-saving lamp accidentally breaks, there is even a health hazard. No wonder, then, that many consumers felt that they were forced to switch to compact fluorescent lamps.

The most important purchase criteria for LED lamps

In order to get an LED lamp suitable for your room, you should consider five criteria:

  • The energy efficiency
  • The brightness
  • The color rendering
  • The blinding
  • The coziness.

LED lamps are environmentally friendly, durable and inexpensive

LED lamps, on the other hand, do not contain any harmful mercury, but also consume little electricity and last longer. In addition, they are more robust against frequent switching on and off.

TheEnergy efficiencyis indicated on the packaging. Here the EU energy label gives information about how much energy the light source is. A +++ is currently the highest energy efficiency class for LEDs and other energy-saving lamps.

The lamps have different switching cycles:

  • Halogen lamps: Switching cycle of 8,000
  • Energy lamps: Switching cycle of up to 30,000
  • Led Lamps: Switching cycle of around 50,000.

Many earlier tests have shown that energy-saving lamps usually can withstand even fewer switching cycles in practice.

For their long-term cost comparison, Stiftung Warentest looked at four halogen, two fluorescent and only one LED lamp for twelve years. In the end, the total costs for acquisition and power consumption for halogen lamps amounted to a total of 200 euros and for energy-saving lamps to 87 euros. The LED performed best with a total cost of only 59 euros and was also ahead in the ecological balance. Of course, the values ​​depend on the costs that you pay per kilowatt hour.

A simple rule of thumb reveals the number of lumens you need

How brightly LEDs shine is indicated on the packaging in the unit lumen (lm). An old 40 watt incandescent lamp, for example, has a brightness of around 390 lm. As a rough rule of thumb, you can calculate the wattage of the previous incandescent lamp times ten and then know roughly the lumen value of an equally bright LED. The table shows in more detail how many lumens correspond to the brightness of old light bulbs:

Bulb wattage

Brightness of the lightbulb

Brightness of the LED

25 watts

230 lumens

250 lumens

40 watts

430 lumens

500 lumens

60 watts

730 lumens

800 lumens

For the LED lamp brightnessyou should pay attention to both the lumen and the lux value. The lumen value indicates how bright the LED is. If you only want to illuminate a certain area - for example the dining or work table - you should pay attention to the lux value. The higher this is, the lighter the surface below is irradiated. Experts recommend 300 lux. For the work area in the kitchen and desks, 500 lux is recommended.

Note the beam angle for LED lamps

Unlike the earlier incandescent lamps, the light from LEDs is focused. Classically, they shine as spot light and do not scatter the light evenly. This is not ideal for ceiling lights that are supposed to illuminate an entire room as evenly as possible. The so-called half-value angle provides information on how evenly the light source distributes its light. This is the angle of the light cone at which the light intensity of the lamp is at least half of its maximum - which a 400 lumen LED, for example, still illuminates to at least 200 lumens.

For spot lighting or to illuminate an object, a picture or the like with an LED, LEDs with a half-value angle of 35 degrees are used. In order to illuminate a room - for example in the ceiling light - LEDs with a half-value angle of 120 degrees are used.

Diversity is a big plus of LED lamps

A big plus of LEDs is their versatility. The bulbs are available in a variety. LED light sources are now available for almost all lamp sockets. The shapes of the LEDs are no less diverse. The light sources can be shaped in the same way as the earlier light bulbs. They are also available in candle form, for example, so that they can also be used in chandeliers, wall torches or other lights in which the lamp is visible.

Warm light with LEDs: Pay attention to the light color

The color temperature (light color) is specified in the unit Kelvin (K). It describes whether the white light is more yellowish-warm or bluish-cool.

  • Warm white light resembles late daylight. It looks cozy and relaxing.
  • Neutral white light has an activating effect.
  • Daylight white promotes concentration.

As the graphic shows, color temperatures up to 3,300 K are referred to as warm white, color temperatures from 3,300 K to 5,300 K as neutral white and above 5,300 K as daylight white:

Source: Paulmann Licht GmbH

Pay attention to the CRI value or color rendering index

The Association of German Engineers (VDI) also advises paying attention to the so-called "Color Rendering Index" (CRI) when buying LEDs. The CRI value, sometimes also given as the color rendering index Ra, describes how well you can recognize and differentiate colors in the light of a lamp.

Street lighting, for example, has a very low value because it is difficult to distinguish colors in its orange light. According to the VDI, fluorescent and energy-saving lamps in the standard version also have a bad CRI value. Their light appears yellow-greenish and makes the skin look pale. Dark blue and black are also often difficult to distinguish in their light.

The quality of the color reproduction is indicated with a number from 1 to 100. For normal lighting requirements, a value greater than 80 in the household is sufficient, according to the VDI. 100 corresponds to daylight. Unfortunately, not all manufacturers indicate the CRI value on the packaging.

Pay attention to the frame and the shape

In addition to the lumen and wattage, you should also pay attention to the socket of the lamp. Because not all of them fit in the base of your lamp. In addition to turning devices, there are also plug-in bases. The common types of sockets for LED lamps are:

Overview of the LED socket (source: Elting GmbH)

In addition to the socket, the shape of the light source is also important. For example, it may be that a globe-shaped LED does not fit into the screen, as it is only large enough for the bulb LED. There is also a candle shape and the spot.

Avoid glare

Glare bulbs are not only uncomfortable for the eyes. In the long run, they can also lead to fatigue and a lack of concentration. Glare can also increase the risk of accidents. If possible, you should cover LEDs with a lampshade so that nobody is blinded. It is important to ensure that the luminosity of the LED is weakened by the screen. It may therefore be that you need LEDs with a higher luminosity for umbrella lamps if they are to illuminate the room accordingly.

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