FAQ - Lighting

Technical terms

Beam angle

The beam angle (half-value angle) is the angle between two imaginary straight lines in one plane through the optical beam axis. These straight lines pass through the center of the lamp's terminating front and through the points where the illuminance is 50% of the illuminance on the optical beam axis.


The illuminance is the luminous flux (lm) per area (m²) and is expressed in lux (lx). It is a measure of the brightness with which a surface is illuminated.


COB stands for "Chip on Board". A COB-LED does not consist of several SMD-LEDs, but of a full area LED-semiconductor layer directly on the carrier material of the luminaire. This enables a homogeneous light emission instead of single light spots.

Energy efficiency class

The energy efficiency class provides information on the corresponding energy consumption. Lamps and luminaires are divided into classes E to A++. LED luminaires achieve the highest classes A to A++.

color binning

The value describes the deviation of the color temperature during sorting of LEDs during production, e.g. ±200 K.

Color temperature and light color

The color temperature describes the color impression of a white light source and is specified in Kelvin (K). The lower the color temperature, the warmer the light color; the higher the color temperature, the colder the light color. Häfele refers to white light sources with a color temperature lower than 3400 K as "warm white", while white light sources with a color temperature in the range between 3400 K and 5700 K are called "cool white". Above 5700 K, white light sources are referred to as "daylight white".

Color rendering index

The color rendering index is a quantity that can be used to describe the quality of the color rendering of light sources at the same color temperature. The higher the value, the better the color rendering. The value 100 corresponds to the color rendering of daylight.

Weighted energy consumption

The weighted energy consumption shows the energy consumption in kilowatt hours related to 1,000 hours of use.


The lifetime is the time after which the LED still emits about 70% of its original luminous flux. The efficiency of the LED decreases thus in this time around approx. 30%. The lifetime is strongly influenced by the external effects of temperature, humidity and overvoltage.


A light-emitting diode (LED) is a semiconductor element that generates light when electricity flows through it. This semiconductor element consists of a crystal mounted on a metal holder; both are encased in a plastic protection. LEDs are usually based on inorganic, i.e. non-carbon materials.

Luminous efficacy

The luminous efficiency is the ratio of luminous flux and absorbed electrical power. It is the measure for the economic efficiency of the light source. The luminous efficacy is expressed in lumens per watt (lm/W).

Luminous flux

The luminous flux is the light output, i.e. the amount of light emitted by a light source, and is expressed in lumens (lm).


The light color of white tones can be changed as required, e.g. from warm white to cool White.


A light emitting diode consisting of several organic semiconductors (Organic Light Emitting Diode). Currently still too inefficient as a light, but interesting for future development.

Test marks & symbols

Click on the Link to call up an overview of the check marks and symbols.


Inductive charging of suitable mobile devices, e.g. smartphones. Unsuitable end devices can be upgraded via special charging sleeves.


RGB is the abbreviation for red, green and blue. In combination with a color mixing device, the three basic colors can produce almost any number of color combinations.


SMD stands for "Surface Mounted Device" and describes electronic components with solder contacts directly on the housing instead of connecting wires. This allows a small space requirement and a good thermal connection. SMD LEDs are used in LED strips, for example.

Technical questions

Is there a rule of thumb/rule of thumb for power design for ceiling lights?

for 2.5 m room height.

Kitchen + living space:

  • fluorescent lamps 2.5 W/m2
  • LED lights 1.25 W/m2


  • fluorescent lamps 6 W/m2
  • LED lights 4 W/m2

Where can I find LED 230 V switch accessories?

Radio controls and switches for LED 230 V can be found in the range of switches and sockets 230 V.

What is meant by series connection?

The lights are connected in series in a switching circuit. If an LED fails, the current flow is interrupted. Therefore free slots must be occupied with the supplied cable bridges. All lights and switches must be connected to the power supply unit before the connection to the mains is made.

What is meant by parallel connection?

The lights are connected in parallel in a circuit. If one light fails, all other lights continue to light up. A cable bridge is not necessary.

How can I compare the performance of an LED with a halogen lamp?

Use the light cone and compare the values at 500 mm. A halogen lamp with 20 W produces approx. 600 lx at 500 mm.

What is the difference between LED ribbon and LED silicone strip?

LED silicone strips are encased with silicone, which means no profiles are needed for mounting. The LED silicone strips can be mounted directly in a groove or on a surface. The silicone sheathing slightly increases the color temperature. LED stripes are without silicone, and it is recommended to use aluminum profiles for mounting and thermal Management.

Can an LED strip be used behind an acrylic glass?

Yes, but the acrylic glass increases the color differences (binning) by a factor of 4 and minimal color deviations become more visible.

What influence does the design of the glass edge have on the lighting effect created?

The lighting effect varies depending on the type of glass base.
Glass edge satinized = uniform light line
glass edge clear = point light

What should be considered with RGB bands?

In order to achieve a homogeneous color gradient, RGB bands with multi-color LED chips are generally recommended, i.e. each LED chip contains all three primary colors. The performance of the color mixing device must be taken into account.

Is pure white light possible with an RGB band?

No, a pure white light color is not possible by mixing the 3 basic colors with RGB.

Why is it necessary to plug in the lights first before connecting the main plug?

If the power supply is connected to the power supply first, there will be an electrical power output on the secondary side, which leads to overvoltage and thus to damage to the lights when they are connected.

What current carrying capacity and power is permissible?

 Häfele allows the following current carrying capacity and power

The cable type is printed on the sheathing of the cable.

How many watts maximum can I connect to a consumer output on the power supply?

For 12 V systems, this is 12 V x 3.5 A = 42 W on a 60 W power supply unit.
For 24 V systems, the power consumption on a 90 W power supply unit is 24 V x 3.5 A = 84 W.

What do I have to consider when installing power supplies?

When installing power supply units, maintain a minimum distance of 50 mm on all sides. Ensure air supply and circulation. Maximum ambient temperature see installation instructions. The power supply unit must be protected against overvoltage. Deviating handling may result in damage to performance and service life.

What is the maximum cable length between power supply and light/switch?

6 meters between power supply and lamp or between power supply and switch. With longer cables the loss of power is too high.

May I use power supplies from other manufacturers?

To ensure the safety and function of the installation, only Loox power supplies or power supplies expressly approved by Häfele may be used.

What is the heat development of LEDs?

LEDs also generate heat. However, they will not glow as hot as halogen, for example.

How is a consistent light color of the illuminants guaranteed?

Häfele sets a high quality standard for the selection of materials. The definition of a narrow binning range is one of these criteria, along with sorting according to luminous flux and breakdown voltage, and ensures the same light color for subsequent purchases.

What is the difference between lamp and luminaire?

Lamp means the light source, e.g. an incandescent lamp; luminaire means the light fixture with the light source.

Lighting effects and lighting technology

Light cone, illuminant & luminous efficiency in comparison

Click on the Link to call up the explanation of the light cone and illuminant & Comparison of light efficiency 

Light colors and typical applications

Click on the Link to call up information on the light colors and typical applications.

Permissible LED tape lengths


Which lights can be used in wet areas?

If luminaires are to be installed in rooms with a bathtub, shower and washbasin, the zones and types of protection listed below must be taken into account when selecting products with regard to protection against moisture and water. The selection and installation must exclude any danger from electrical currents.

The figure and the following explanations show the European Standard. No liability is assumed for the correctness of the information.

Zone 0 / Protection class IPX7:

Installation of lighting in the bath or shower tub. Only low-voltage systems (max. 12 V alternating voltage), which are protected against permanent immersion, may be used here.

Zone 1 / Schutzart IPX4:

Area above zone 0 (bathtub, shower cubicle or sink) up to 2.25 m in height. If the water connection, e.g. for showers, is above this, then up to this height. Applies to areas above and below bathtubs and showers. If there is the possibility of jet water, e.g. through water jets for massage, protection class IPX5 is required! Transformers must be located outside zone 1, unless the supply line and transformer are permanently connected to the luminaire and are waterproof.

Zone 2 / Protection class IPX4:

Connects to zone 1. Applies to areas around the bathtub or shower with a depth of 60 cm or a radius of 60 cm for hand basins. If there is the possibility of water jets, e.g. through water jets for massage, protection class IPX5 is required!

Zone 3:

Anywhere outside zone 0, 1 and 2.


Why does the light flash briefly at regular intervals when switched off?

The cause is a leakage current in the electrical installation, which charges the capacitor in the power supply unit until it delivers the power at regular intervals for a short time for discharging and thus the lights flash briefly.
Solution: Check the complete Installation.

Why is my LED light flashing?

Flashing is a sign of (under- or) overload.
Use a power supply with higher power or reduce the number of consumers.

What can be the reason that only single colors are displayed in an RGB band?

The clip connector has been connected the wrong way round or the strip has been connected at the wrong end or to the power supply.

Why does my wireless remote control not work properly?

The clip connector is not correctly attached, the remote control is not correctly initialized (learned) or other devices in the room are sending interference signals, e.g. radio loudspeakers.

How to avoid malfunctions of the sensor switches (diameter 12 mm)

Check correct installation of the switch. The TOP inscription on the switch must point upwards in the installation Situation.

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