Friday, 19 August 2011

Watts , Lux, Lumens, LEDs, and inacndescent lights

For a more detailed explanation, see this web site, but as a rough comparison, think of these points:

Lumen s measure the total number of packets of light produced by a light source

To compare watts to light output and LED bulbs, we talk about ‘lumens per watt’ (lm/w).

Incandescent bulbs generate around 12 lm/w,
(so a 60watt bulb produces approximately 720 lumen)

LEDs and halogen lights are almost equivalent at 40 lm/w.
(so a 60watt halogen down-light produces approximately 2400 lumen)

Fluorescent tubes can produce 60 lm/w
(so a 60watt fluoro tube produces approximately 3600 lumen)

So for only 3 watts of consumed power, a single 3 watt CREE LED can produce 120 lumen (about the same as a 10watt incandescent bulb), while a 27 watt LED lamp (9x 3watt CREE LEDs) can produce 1080 lumen ... as much as a 90watt incandescent globe ... for only 27wats consumed !

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