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October 2017
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What is a lumen?

Think of lumens as a “modern” way of identifying how bright a light is. Lumens = Light Output.

In simple terms, Lumens (denoted by lm) are a measure of the total value of noticeable light (to the human eye) from a lamp or light source. The greater the lumen number the “brighter” the light will look.

We have all purchased 50W or 60W conventional bulbs or spotlights in the past expecting a particular level of brightness. This wrongly linked power consumption (Watts) to light output.

More light, less energy (Watts) with LED

Using low energy LED lights, a greater light output can be delivered with much less power usage. For instance, a 6.5W LED light will provide a similar light output to a 50W Halogen bulb. That’s 87% less energy for the identical light output! While using LED extra energy is converted into light instead of heat. While technology advances, extra lumens will be generated using even fewer Watts – i.e. increased lumens per Watt. Therefore, as a result, using Watts as a guide to brightness is no longer of importance.

Lumens – Conventional vs LED lights

To produce a similar light production of a 60W standard bulb you will require an LED lamp with around 800 – 850 lumens. Each LED light happens to have the lumen rating distinctly indicated on the packaging and on the base of the light. in addition to this, a conversion guide to the “old wattages” can be found below.

 

Lumens and Helpful Lumens

For non-directional bulbs such as a globe, golf ball or candle shape, the whole lumen output is measured for all directions. With a directional bulb such as GU10 spotlight, the light is emitted in various directions, some of this light (spill light) may not be helpful but it is included in the total lumen rating.

To make comparisons fairer and simpler the EU has recently started a “useful lumens” rating. This is a measurement of useful light emitted in a standardized 90-degree cone. The “useful lumen” rating is usually lower than the whole lumen output but has more significance to a spotlight bulb where useful light is in a forward-focused direction.

How many lumens do I require?

There is no specific answer – it will depend on multiple factors including; room size and shape, the height of ceilings, colour scheme, type of lamps & fitting, task areas and requirements of the user.

As a primary guide; following are the lumens needed per Sq M (10.76 sq ft) for various room settings. In several cases, a blend of general and task lighting will be needed.

 

 


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