LUMEN vs LUX: The Lighting Industry’s Biggest Lie

Lux

Before Lumen and Lux, there was RMS confusion

Do you remember PPI Art Series amplifiers for mobile audio? As you may recall, the RMS watt rating that was on the package is what you got. Then the market started changing. Overseas factories raced to have the lowest cost highest RMS rated amps as possible and we discovered that the RMS wattage that was advertised wasn’t always what you got to your speakers. The same confusion exists today about Lumen and Lux output on lighting products. But have no fear, Race Sport® is here to expose the lies and set the record straight about how to measure light output consistently and in a way that makes the measurement practically valuable. We need to learn from the past.

First, a Story about LUX

Here is a resent example of a similar story in the lighting category. A Race Sport Lighting® sales representative stopped in to check on a local dealer whose sales had dipped. The rep wanted to assist the dealer in reinvigorating their lighting business. When he spoke with the store owner, he discovered that he was considering switching their LED headlight business to a competitor. After a short inquiry into the reasoning for this, the dealer expressed that they could get a 6,000 lumen LED kit from the new supplier compared to our 2,200 Lux Terminator LED kits. The sales rep (having faced this situation before) corrected the dealer on the misconceptions about lumen vs lux and why we at Race Sport Lighting® have been debunking myths about light output for years. We can all breathe easy though, because the dealer made the educated choice to keep his business with us. Below is a breakdown of what that rep shared with that dealer.

Now, for Some Science

Lumen

Lumens are now the most common measurement for lighting companies. The lumen (lm) is a measurement of the total amount of visible light around a light source. Let’s apply this to the LED diodes lighting manufactures like us utilize in building LED products. Each diode is measured in a rage or flux. (Resembling RMS/Peak Wattage on amps) Let’s say each LED diode used in a LED headlight kit has a minimum typical output of 260 lm. With 4 diodes present on the lamp’s circuit board, that means the raw lumen measurement is 1,040 per lamp (2,080 lm per kit). This is how you will see most lighting products measured.

In other words, Lumens are how much raw light is given off from the headlight lamp itself.

Lux

Lux (lx), on the other hand, measures luminance, or the amount of light on a surface.  A single lux is equal to one lumen per square meter.  Now, any change in distance or bulb type changes the lux level.  As an example, if you place a 100-lumen bulb in a flood light that shines on only one square meter of a surface, that surface will be lit at 100 lx.  However, if you back the flood light away to shine on four square meters, the surface is now lit with 25 lx. Thus, Lux is how bright your surface will be.

In other words, Lux is the usable light on the road

Finally, the Exposing of Lies

Lie #1- Manufacturers Misdirect with Lumens

We are not claiming that every lighting manufacturer does this intentionally, or even knowingly. What we are exposing is the habit of some to take a cookie cutter LED product from a Chinese factory, slap an unverified raw lumen output on the box and bring it to market. Let’s go back to the 12 volt manufacture who is attempting to branch out into lighting and their 6,000 lm kit we mentioned above. We investigated and found that the diode they are using measures at 270 lm typically. The lamps come with 6 diodes for a total of 1,620 lm per lamp. You can then double this because there are two lamps, for a realistic total of 3,240 lm per kit. Where the 6,000 lm measurement that is on their website and packaging came from, we don’t know. We will let you decide.

Lie #2- High Lumen Does NOT Necessarily Mean More Functional Light

When you are driving at night what matters is the light on the road. Not the raw lumens of the lamp, but the functional lux appearing on the surface. An LED headlight kit advertised with an exceptionally high lumen output doesn’t necessarily mean you will receive a functional amount of light on the surface. So, when we say a kit is 2,700 Lux (GEN3® LED) we are communicating the usable light on the surface (in this case, the road).

Closing Thought

In closing, we believe the automotive and off-road lighting industry needs to change the conversation from lumens to functional lux. Not doing so leaves the opportunity for misdirection and confusion. Race Sport Lighting® has been committed for years to debunking this confusion and communicating the actual usable light output you will see down the road. Thus helping our dealers and end users make the educated choice when it comes to lighting upgrades for their vehicles. All of our products are tested in our lab for Lux output. So, we can deliver to you a high performing solution with real specifications and functional light output. Watch the video below more detailed information about our testing procedures and the complete Race Sport Lighting® advantage.

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