21 September 2011 | News | Posted by Si-Lite
How bright is that lamp?
With the advent of the LED lamp there is growing confusion over what light output each lamp actually delivers. Many lamps are marketed by their wattage, which tends to suggest that a 5w lamp is brighter than a 4w lamp – but as the song says, “It ain’t necessarily so”. The key factors of determining light output of any lighting fixture are the lux or lumen output and the beam angle.
The wattage given simply advises the power required to run the lamp, not how bright it is. Furthermore, on 1 September 2010, European Union legislation was introduced to mandate that lighting equipment must be labeled primarily in terms of lumens, rather than watts of electricity consumed.
Why do this?
For clarity – enabling the installer and the consumer to have a clear comparable system for understanding brightness and energy usage.
The Lumen is the derived unit of luminous flux – a measure of the total amount of visible light emitted by a source.
The Lux is a measure of how much luminous flux is spread over a given area, and generally in terms of the intensity of light upon a surface (for example, all Si Lite products are measured with a Lux level at 1 metre from the source).
One lux is equal to one lumen per square metre.
A given amount of light will illuminate a surface more dimly if it is spread over a larger area, so the beam angle will give guidance to how widespread the light delivered actually is.
The Si Lite SL400 (MR16) & SL450 (GU10) LED lamps offer 300 lux at 1 metre, and have a 45⁰ beam angle. Rated at only 4w of power per lamp, they actually deliver a superior light output and wider beam angle than some competitors 5w and 6w lamps. In reality, the Si Lite lamp is brighter and is more efficient!
All Si Lite lamps and fixtures are provided with a lux rating at 1 metre, plus a beam angle. So, when you’re considering which LED lamp best meets your needs, remember to check the lux / lumen rating and the beam angle – then decide.