The LUX of lighting

What is LUX? It is generally a measure of the intensity of light produced by any lighting device. The higher the LUX measurement, the more light available on a specific area. This is usually discussed in terms of “lumens” per square meter.

Okay, so you might say, what the heck is Lumens? This is something that is also discussed in different terms, but more often refers to the “foot candles” produced by the light source.

To simplify and clarify the whole matter, let’s take a single candlestick as an example. If you light that candle in a dark room, you’ll be able to measure the amount of light it generated a foot away from the flame. This amount of “illuminance”, or the result of using a light of any kind, is how LUX is measured. It is the degree to which an object is illuminated, but not the total amount of light produced by the light source. This is something that refers to the measurements in English, so LUX is spoken of as a lumen per square meter of illuminated surface.

So how does this fit into any kind of incandescent versus LED lighting discussion? The average household incandescent light bulb can typically put out a thousand lumens when new. LED bulbs have just entered the market with the same capabilities (around 1050 lumens for the cool white lights and 760 for the warm white variants). The biggest differences between the two options are the amount of energy consumed in their use. The LED produced 72 lumens per watt, while the incandescent equivalent could only produce a maximum of 5 at 17.5 lumens per watt.

Older bulbs are not only much less efficient, but they also lose their lumen quality considerably faster, produce unnecessary amounts of heat, and also require replacement much more frequently. For example, the lumen maintenance in an LED bulb will have around 70% retention over the bulb’s standard 50,000 hour lifespan. An incandescent bulb tends to burn out at a constant voltage which rapidly evaporates the filament, the rate at which this occurs is usually published on the bulb packaging as “Rated Initial Lumens” and “Approximate Average Lumens”. This data varies, but tends to be significantly lower, with an average of 80% for only two thousand hours of life.