LED FAQ
LED FAQ
Quality features of a good LED
Every LED and every SMD LED chip needs cooling, from simple LED strips and LED bulbs to high-bay luminaires. If the thermal management is poor, the LED light source will quickly lose brightness and become dimmer. An LED converts less energy into heat than conventional lighting, but the heat that is generated must be dissipated. There are many different ways to cool an LED; the most common is an aluminum heat sink. Cooling fins provide a large surface area for optimal heat dissipation.
electronics
Every system is only as strong as its weakest link.
With an LED, you're acquiring a piece of technology. Every LED light needs electronics somewhere, either through an external constant current source or through internally installed components. High-quality LED lamps and lights have electronics designed for a long lifespan. Of course, even these can fail occasionally – but this usually happens well within the warranty period.
The LED itself
life
The long lifespan of an LED can only be guaranteed if the thermal management and electronics are designed accordingly. The lifespan of an LED lamp is specified, for example, as 50,000 hours. This means that after 50,000 hours, the LED still retains 70% of its light output, 10% may have failed due to a defect, and the remaining 20% is reduced by the aging process.
If the LED stays cool and the electronics cooperate, LED lighting is a purchase for a longer period of time, a reason not only to look at these data, but also to take a look at the actual value of the purchase: the light itself.
Light color
The days of cool, blue LED light are over. LED lamps in a wide range of light colors are now available: from warm white tones for living room lighting (K2700 to K3000), to neutral white LEDs for office lighting (K4000), and even daylight white (K6500), everything is now possible.
Since LEDs naturally emit cooler light, the warm white light is achieved through a phosphor coating. Due to variations in the coating's composition, the warm light color differs slightly from manufacturer to manufacturer.
If possible, test the LED for its color temperature. If the light color doesn't match your project, there's a good chance you'll find a suitable one in another LED.
Binning
However, even within the same manufacturer's product range, variations in light color can occur from batch to batch. High-quality products undergo a sorting process called binning. In this process, the LEDs are assigned to specific parameter classes. The more narrowly defined these classes are, the more expensive the process, but the more accurately the color values match.
Color reproduction
The colors that are reproduced depend on the spectrum of the light source. Depending on the application, this is either less important or crucial. The color rendering index (CRI) is given in Ra.
In an office environment, this value should be greater than 80Ra, otherwise distorted color reproduction can quickly occur, which is the case with most LEDs.
Replacing conventional light bulbs with LEDs
Many conventional light bulbs can now be replaced by LED light bulbs, but you should keep a few things in mind when switching over:
Basic information on replacing LEDs with retrofit LEDs: Heat dissipation of the LED
LEDs don't get as hot as conventional bulbs. However, they are sensitive to heat buildup. If the heat isn't dissipated, the LED will quickly dim or even fail completely. Therefore, all LED light sources require adequate ventilation.
Light distribution of the LED retrofit:
LEDs generally emit light more evenly than conventional light sources.
LED light color:
LED retrofits are available in many different light colors.
Warm white K2700-3000 comes closest to the conventional light bulb.
Neutral white K4000 is the equivalent of most commercially available energy-saving bulbs.
Daylight white K6500 is very cool and should be used selectively.
The comparison of lumens to watts
Lumen is the luminous flux emitted by a lamp in all directions. In other words, the total light emitted in all directions. However, there is a slight "stumbling block" with LEDs.
LEDs naturally emit their light in one direction. With a conventional fluorescent tube, for example, it's completely different. It emits light evenly in all directions.
Therefore, the luminous flux is directed in the desired direction using reflectors - which involves losses.
With its counterpart - the LED tube - this is not necessary, as the luminous flux exits in one direction.
But as a guideline - combined in the graphic with watts - the lamp's power consumption - it at least provides an indication of the brightness.
The comparison of lumens to watts
Watts were a more or less meaningful unit of measurement for light bulbs.
Lumen is the unit for the total light emitted by a lamp in all directions. It describes the lamp's brightness. A 40-watt incandescent bulb, for example, has approximately 400 lumens. However, since all other light sources produce more lumens per watt, categorizing a light source solely by wattage is no longer meaningful.
Much more importantly, both specifications are needed - lumens to describe the brightness of a light source and watts to be able to classify the energy consumption of the light source.
The watt is calculated as volts x amperes, denotes power, and, at a given voltage, also indicates power consumption. A light bulb with, for example, 40 watts therefore consumes 40 watt-hours per hour = 0.04 kWh.
Based on this, this light bulb, burning for 10 hours a day, 365 days a year, consumes 146 kWh per year, divided by 1000.
(40 watts x 10 hours x 365 days)/1000 = 146 kWh
So, for this lamp, you would pay 32.12 euros (kWh x electricity price) if the electricity price is, for example, 0.22 euros.
For an LED retrofit lamp with 403 lumens at 5 watts, it looks like this:
(5 watts x 10 hours x 365 days) / 1000 = 18.25 kWh
So, at an electricity price of €0.22, you pay €4.02 for the LED (kWh x electricity price).
Please note - the light output is comparable.
In our example calculation, an LED with 403 lumens costs 4.02 euros in electricity per year, while an equivalent incandescent bulb with approximately 400 lumens costs 32.12 euros in electricity per year.
Illuminance (Lux)
Illuminance is the amount of light – measured, for example, with a lux meter – that effectively falls on a surface. It is expressed in lux. This means that what is measured is how much light actually reaches, for example, your desk – regardless of how many lumens the light source emits. Compliance with standards and guidelines is based on this measurement.
But what does that actually mean?
For example, parking lots often have 20-25 lux at ground level.
In the living area - depending on the lighting, of course - 50 to 200 lux
Public spaces are often illuminated with 200 lux.
You should have at least 500 lux at your desk when concentrating on work.
Sunlight - on a beautiful sunny day - can have 40,000 to 50,000 lux.
Lumen to Lux Conversion
The lumen rating for LED lamps and lights is actually a rather theoretical specification for the end user.
It can be used to compare light sources - but can only be measured in a laboratory.
For the user, however, the achievable illuminance is important. Illuminance in lux can be measured using a lux meter, but it can also be roughly calculated using the specifications of the lamps and luminaires. To do this, you need to know the lamp's lumen output, the beam angle, and the distance to the surface to be illuminated. With this information, you can at least roughly calculate the expected light cone and the illuminance (lux).
The calculation is based on the following formulas:
Luminous intensity (I - candela - cd ) = luminous flux (Φ - lumen - lm ) divided by
Solid angle (Ω - Steradian -sr )
I = Φ/Ω
Illuminance (E - Lux - lx) = Luminous intensity (I - Candela - cd) divided by
radius² or distance
E = I/r²
A GU10 LED with 350 lumens, a beam angle of 35° and a distance to the ground of 2.40 meters achieves a
illuminated area with a diameter of 1.5 meters and an area of 1.80 square meters, a luminous intensity of 1203 candela and an illuminance of 208 lux.
Lumen
Lumen is the luminous flux of a lamp. It's the unit for the "luminous efficacy" of a lamp.
Essentially, it's the total amount of light emitted by the lamp in all directions. A 40-watt incandescent bulb emits approximately 400 lumens in all directions. Like candela, lumen is a unit of measurement and describes the light emitted by the lamp.
Candela
A light source does not emit its light uniformly in all directions. Candela (cd) is the unit that describes the luminous flux emitted by a light source in a specific direction.
Candela, like lumen, is a measurement that describes the perceived intensity of radiation in the eye.
Calculation:
The formula for calculating candela is:
Luminous intensity (I - candela - cd) = luminous flux (Φ - lumen - lm) divided by solid angle (Ω - steradian - sr)
I = Φ / Ω
lux
Illuminance is measured in lux (lx).
It describes how much light from the light source reaches a specific area.
Unlike lumens and candela, lux is a receiver quantity – that is, it measures how much light arrives at a specific point. This takes into account the distance of the surface from the light source and the angle at which it is emitted.
For example, in your office. A light fixture hangs above your desk at a height of 2.40 meters. A lux meter measures 400 lux on your desk. However, the standard requires at least 500 lux. Therefore, your lamp is too weak, and you either need a brighter light or additional lighting.
Light distribution
Using a light distribution curve (see below) and a small formula, you can calculate how many lux still arrive at a given distance.
You simply need to divide the luminous intensity (candela) by the distance (in meters) squared. Sounds complicated – but it's quite simple.
Calculation:
You can calculate the illuminance using the following formula:
Illuminance (E - Lux - lx) = Luminous intensity (I - Candela - cd) divided by radius² or distance²
E = I/r²
This luminous intensity distribution curve shows that the light emits approximately 2750 candela vertically downwards.
This means that at a distance of 3 meters, 2750 cd divided by (3m)² still arrives. That's approximately 305 lux.
However, only this one lamp is considered – no light falling on the surface from other lamps and no light reflected from surfaces (e.g. walls).
The luminous intensity distribution curve indicates how much light is emitted by a lamp at a specific angle. 0° is always directly below the lamp.
This allows you to quickly see whether the lamp emits its light downwards or upwards, whether the light cone of the lamp is narrow or wide, and how much light (in candela) is emitted in one direction.
This luminous intensity distribution curve shows the distribution of light from a downward-facing lamp with a relatively narrow beam.
Color temperature
Color temperature is the color of a lamp's light, measured in Kelvin (K). The color of white lamps can vary greatly.
There are all intermediate shades, from reddish-yellow lamps perceived as warm to bluish lamps perceived as cold.
The following applies:
Lamps with a color temperature of less than 3300 Kelvin are warm white.
Lamps with a color temperature of 3300 to 5300 Kelvin are neutral white.
Lamps with a color temperature of >5300 Kelvin are daylight white.
Color Rendering Index (CRI)
The color rendering index is given as Ra or, in English, as CRI (Color Rendering Index).
The value describes how well a color illuminated by a light source is reproduced.
Colors are displayed differently by different lamps because the spectrum of the lamps differs. Even lamps with the same color temperature can have different spectra.
So, the color rendering is compared with an ideal template, and the lamp is then classified according to the deviation.
A CRI of 100 represents the best color rendering = no deviation from the ideal template; the colors of the illuminated object appear as they do in nature.
For office spaces, only lamps with a color rendering index (CRI) of at least Ra 80 should be used. Rooms where color perception is important require the highest possible CRI (i.e., Ra 90 or higher).
The Ra value of fluorescent lamps is often printed in coded form on the lamp itself.
The printed value 740 means a Ra value of at least 70 (first number) with a color temperature of 4000 Kelvin, 850 means a Ra value of at least 80 with a color temperature of 5000 Kelvin.
LED - the future of lighting technology
We're not the only ones who believe this – many experts in the lighting industry share this view.
LED technology is developing rapidly. While just a few years ago only dim, cool white LED light was available, today there are suitable LED lamps and luminaires for almost every lighting scenario. In many areas, LEDs are superior to conventional solutions.
LED lighting is energy-saving.
Everyone associates that with LED lamps and lights - and it's true.
A 5-watt LED bulb easily replaces a conventional 40-watt incandescent bulb, and a 17-watt LED tube provides the same light output as a conventional 38-watt fluorescent tube. But energy savings are far from the only advantage of LEDs.
LED lighting is long-lasting.
With lifespans sometimes exceeding 50,000 (L70) hours, a good LED lamp is far more durable than conventional light sources [ Generally, the lifespan of LEDs is specified as L70 - meaning that the LED does not fail, but 70% of the initial brightness is still present at the end of the specified hours].
LED lighting is flexible.
Want to illuminate a shelf – or the wall behind a small ledge? LEDs can handle that . These small light sources are even available as adhesive strips (LED strips) that can be cut to size with scissors or extended with connectors. Outdoor lighting and underwater lighting? No problem either – LED strips and many other LED lights can be completely waterproofed.
LED lighting is robust.
No other light source is as resistant to shocks and impacts as LEDs. Fluorescent tubes and energy-saving lamps, due to their glass body containing the luminous gas, must be handled with care – LED lighting is significantly more shock- and shatter-resistant.
LED lighting is gentle on the skin.
Since the light spectrum of LEDs is limited to the visible range, there is no UV or infrared radiation. UV radiation, in particular, can cause plastics and paints to become brittle. LED light is therefore gentler on illuminated surfaces. Another advantage is that insects are attracted to the UV component of LED lighting . This is a significant benefit, especially for indoor and street lighting.
LED lighting is environmentally friendly.
Energy-saving light bulbs contain mercury and must therefore be disposed of as hazardous waste. The danger of a broken energy-saving light bulb lies in the mercury vapors, which are released suddenly.
Here too, LEDs score points, as modern LED lights and LED bulbs contain no toxins and all LED lights are 100% recyclable.
Many advantages - but we also don't want to hide one disadvantage from you.
LED lighting is somewhat more expensive than conventional solutions.
High-quality LED lighting is currently somewhat more expensive than, for example, energy-saving lamps or fluorescent tubes. However, this only applies to the purchase price. When you factor in energy costs, maintenance costs, lifespan, and the other advantages of LEDs, you quickly see a profit, and the initial investment is fully recouped in a very short time!
What are LEDs?
Light-emitting diodes (LEDs = light-emitting diodes) are based on semiconductor compounds that convert electricity directly into light . In simpler terms, a semiconductor crystal is stimulated to emit light by an electric current.
In practice, this works so well that LED lamps (because of their enormous advantages) are increasingly replacing conventional types of lamps.
What are the advantages of LED technology?
Many many!
First of all, there's the enormous energy saving. LED lamps consume up to 20% less electricity than, for example, energy-saving lamps. Incidentally, less energy is also consumed in the production of an LED.
An LED lasts longer than conventional bulbs. Good LED bulbs can last up to 50,000 hours. That means (with 6 hours of continuous use per day) almost 23 years of light. And that's not all. LEDs are small, versatile, shock-resistant, and the light is instant.
Isn't the LED light too "cold"?
That was then. Today you can get LED lamps in all light colors and with very good color rendering.
LED lamps always look so technical!
But no – thanks to its highly versatile technology , LED lighting has opened up a whole new world of design possibilities. Just take a look around our shop – you'll be amazed at the design options available!
But LED lamps are expensive!
It depends on how you calculate it. Good LEDs are certainly a bit more expensive to buy, but they pay for themselves quickly through electricity costs and the elimination of maintenance.
What do I need to be aware of?
In principle, not much - provided you buy a good LED lamp or light fixture.
Like all other technologies, LEDs also have their challenges. For example, the heat generated must be dissipated effectively, otherwise the lifespan is reduced. We have given this a lot of thought for you (not least in the selection of manufacturers). This is one reason why we offer you only top-quality LEDs, so that you can enjoy our products for a long time.
Where can I use LED lamps?
You can replace your existing lamps with LED retrofit lamps practically anywhere.
In our shop you will find a large selection of these types of lamps. Simply unscrew your old one and replace it with a modern LED version.
And then there's a lot of LED technology for outdoor use, indoor use, ceiling, floor or wall - nowadays there's something for everyone.
You can find those in our shop too.
And what about the environment?
We've already discussed energy savings. But LED lamps also have the edge before and after use in your home. Producing an LED lamp consumes far less energy than manufacturing all conventional lamp types. Not to mention the mercury, which is not present in this type of lamp. Disposal (after a long lifespan) is also simpler. LEDs are simply electronic waste and not hazardous waste (like, for example, energy-guzzling lamps and fluorescent tubes).
Is everything clear? No?
No problem, just contact us. We'll help you from choosing the right lamps to developing a lighting concept for your space.