Converting Watts into Lumen: let's illuminate you!
Lumen
What are lumens?
Lumen (lm) is the unit of measure for luminous flux. The lumen value measures the amount of light emitted by a lamp. The term "lumen" is Latin and means "light".
Anyone still looking at watts when deciding on buying a luminaire, will most likely be left in the dark. The one measurement that counts in modern LED lighting technology is lumen – a unit of measure that much better describes the brightness of a lamp than its watt value.
Converting watt to lumen
No problem if you are having a hard time getting away from the more familiar idea of watt. The watt to lumen conversion is easy. So... how do you go about stepping out of the dark and into the light? Here is an easy rule of thumb to follow:
Conventional wattage x 10 = lumen value
Lumen is a more precise measurement for the brightness of a lamp than watt.
What is the difference between omnidirectional lamps and reflectors?
The lumen value (lm) indicates the luminous flux or the total amount of light emitted by a lamp. The type of illuminant, i.e. omnidirectional lamp (bulb shaped) or reflector lamp makes no difference.
The brightness of omnidirectional lamps and reflectors is, however, calculated on a different basis:
Lumen in omnidirectional lamps
The unit of measure lumen (lm) states the total amount of light that an omnidirectional lamp emits in terms of luminous flux.
The unit of measure lumen (lm) states the total amount of light that an omnidirectional lamp emits in terms of luminous flux.
All reflector lamps with a beam angle of up to 90° are labelled as "luminous flux in a 90° angle" and are therefore comparable. Brightness is measured within the 90° angle, even if the actual beam angle is smaller.
All reflector lamps with a beam angle of 91° to 120° are labelled as "luminous flux in a 120° angle". These lamps are not suitable for accent lighting.
All lamps with less than 80% of their total luminous flux in a 120° beam angle are categorised as "non-directional light" or "general diffuse lamps". They are labelled in lumen (lm), which describes the complete 360° light output around the lamp.
Nobody is talking about watts any more
Modern luminaires come with significantly lower watt values than traditional incandescent light bulbs. The technical information on the packaging usually includes values between 5 and 10 watt. That is mostly due to the fact that state-of-the-art light technology consumes much less energy. The wattage of modern luminaires doesn’t tell you much about the brightness you can expect.
Think about what you will be using a particular space for, what kind of ambiance you want to create and how much light you will need to do that.
