FAQ: LED terms you should know
Buying new lighting can be more complicated than that. For example, do you know all the lighting terms in the data sheet or on the packaging? You don't? Then you're not alone! In this week's blog post, we take a closer look at some of these terms. What does candela mean? And is CRI important to me? We regularly get asked about the meaning of the lighting terms we have in our data sheets, so we've decided to put it all together in one big FAQ to clear up any doubts.
Lumen (lm)
Lumen means luminous flux and measures how much light comes out of a light source. In other words, the higher the lumen value, the more light the light source emits.
If you are using LED modules in your home, you should therefore be careful not to choose luminaires with too high a lumen output. An example would be our recessed spotlight NS14, which emits 420lm.
However, if you need to light up an entire warehouse, you should buy a luminaire with a high lumen output. For example, our powerful NS91 LED luminaire, which emits up to 250,000lm.
Watt (W)
Watt is the lighting engineering term for power consumption, meaning that the higher the wattage, the higher the power consumption.
When replacing your traditional lighting with LED, it's easy to make the mistake of looking for an LED bulb with the same power consumption as the halogen bulb you already have. However, the wattage only tells you the power consumption and not the actual energy efficiency.
For example, our 7W LED downlight NS14 is equivalent to a 50W halogen bulb.
Lumens per Watt (lm/W or LPW)
To measure energy efficiency, you don't need to look at lumens or watts in isolation. Instead, you need to look at the concept of lumens per watt, which is measured by dividing the lumen output by the number of watts consumed by the given luminaire. A high lm/W equals an energy-efficient light source.
Our most energy-efficient luminaire is our OS0029 LED tube. With a lumen output of 2,850lm and a power consumption of 15W, the luminaire has an energy efficiency of 190 lm/W. In comparison, an incandescent bulb emits 10 lm/W.
Kelvin (K)
The Kelvin scale measures the color temperature of a light source on a scale from 1,000 to 10,000 K. Warm light, such as the light from a candle, has a low Kelvin value of 1,200 K, whereas cold light, such as a clear blue sky, has a high Kelvin value of 10,000 K.
The Kelvin value is therefore important for the atmosphere you want to create. For example, if you want to illuminate a restaurant with a cozy and intimate light, you should choose luminaires with a low Kelvin value. On the other hand, if you are lighting a museum where the light should be as realistic as possible, you should choose a luminaire with 5,000 K.
The vast majority of our products can be ordered with the Kelvin value that suits you. For example, our NS60 LED panel is available with either 3,000, 4,000 or 5,000 K.
Color rendering (CRI)
However, if you are interested in how well colors are reproduced, you should keep an eye on the CRI of the luminaire. CRI indicates how the light source renders colors in a room on a scale from 0 to 100.
For indoor lighting, there is a minimum requirement of CRI80. For outdoor use, less may be sufficient. However, if the lighting is to be used in an operating room or restaurant kitchen, CRI90+ light sources should be used.
With most of our products, it is possible to opt for a higher color rendering. An example of one of our luminaires with the highest color rendering is our track spot NS70 with CRI90+.
MacAdam (SDCM)
MacAdam indicates the color stability of a luminaire on a scale from 1 to 10, where 1 is the desired value. A high MacAdam therefore equals an impure light, whereas with a low MacAdam of 2 or 3, you won't see a significant difference in light color.
Most of our products have a MacAdam of 3, and several of these can be upgraded to a MacAdam of 2. For example, our elongated LED spotlight NS22.
Candela (cd)
Candela describes the brightness of the luminaire in a certain direction and is used to calculate lumen output, for example. However, you will rarely need to investigate candela further.
Lux (lx)
The lux value indicates how much light hits a given surface. In other words, the lux value depends on the room and the items placed in the room. In Denmark, there is a minimum requirement of 500 lx in offices, and especially in Europe, there are rules for the lux value.
What can we help with?
Do you have further questions about lighting technology terms or is there something we need to clarify? Then contact us right away! Our LED experts are ready to help you.