how many watts needed to produce 2500 lux?

Question

I need a light box due to having SAD and wondered what the watts are in the bulbs in the lamp if the lamp produces 2500 lux

Answer 1

A lux is defined as 1 lumen per square meter. A 100 watt incandescent puts out around 1200 lumens. A compact fluorescent of about 26 watts does about the same. The lux rating depends on how far away you are and how you build the reflector. For a distance of 2 feet from a bare bulb, 1200 lumens gives you 250 lux. Even a pretty crude reflector can double the flux. This means you need about 6000 lumens or 5 good sized compact fluorescent bulbs (26 watt is a standard size) for 130 watts total. Since you need such a high flux, they would stay away from incandescents because they put out much more heat than light making such proximity uncomfortable.

Answer 2

300 Lux In Watts

Answer 3

They are necessarily linked:
http://genet.gelighting.com/LightProducts/Dispatcher?REQUEST=RESULTPAGE&CHANNEL=Consumer&FILTER=FT0010:General+Purpose_Standard&CATEGORY=Lamps&BREADCRUMP=General+Purpose_Standard%230

Note that the GE Soft White A19 puts out 1600 lumens at 100 W, while the Reveal A19 puts out only 630 lumens at 60 W.

Compact fluorescent bulbs can sometimes produce as much light as incandescent bulbs with much higher power ratings:
http://genet.gelighting.com/LightProducts/Dispatcher?REQUEST=CONSUMERSPECPAGE&PRODUCTCODE=49685

Answer 4

It depends on the type of bulb you have. A halogen lamp would need one wattage and a flourescent would need another.

Answer 5

Adding to the answers do not forget that the intensity of the light is inversely proportional to the square of the distance from the source to the receiving object or something like that so you need a lot more information.