What does it mean? LED lighting terminology explained

Last modified: 29th Jul 2014

These days energy-saving lighting is fast becoming the norm – and rightly so; the benefits both in environmental and money-saving terms are well known. LED is one form of lighting that has come into the mainstream in recent years, although it’s actually been around in one form or another since the 1960’s. However, there is still some confusion amongst consumers when it comes to LED lighting terminology, so here we explain some of the key terms.


Starting with the acronym LED itself, it stands for Light Emitting Diode and is the name for an electronic component which gives off light. These diodes are assembled into lamps, called luminaires, for use in a range of commercial and domestic applications. LED bulbs are far more energy efficient than conventional incandescent light bulbs, and have a much longer operating life.


With LED lighting, the watt is no longer an indication of brightness as most people are used to with traditional bulbs. Though wattage is still shown on LED bulbs, this is purely an indicator of their power consumption. The measurement to look out for is the lumen (lm), and the higher the lumen, the brighter the bulb. 230lm is equivalent to a traditional 25W bulb, and at the opposite end of the scale, 1340lm is about as bright as an old 100W light bulb.

LED driver

As LEDs operate on DC power, they require electronics in the luminaire to convert mains electricity and power the light source. This is called the driver.

Lumen depreciation

Unlike conventional light bulbs, LED lighting doesn’t simply ‘burn out’ like old-fashioned bulbs when it reaches the end of its useful life (except in the case of driver failure). Instead, its light output gradually decreases over a long period of time, known as lumen depreciation. The widely-accepted standard is L70, which is the point at which light output falls below 70% of its original level. This measurement shows the number of operating hours you can expect from the LED before its output falls below a useful level.

Colour temperature

Colour temperature is an often misunderstood piece of LED lighting terminology. Frequently referred to simply as LED colour, this is a measurement which indicates the warmth of the light emitted from the luminaire. It is measured in degrees Kelvin and, put simply, the higher the number, the whiter the light. The most common colour temperatures are as follows:

We hope this explanation of LED lighting technology has helped to (pardon the pun) enlighten you!