10,000 Lux
10,000 lux is the headline brightness number most often used in SAD lamp shopping. The buyer question is not just whether the lamp can reach 10,000 lux, but whether it can do that at a realistic sitting distance.
What it means in plain English
Lux measures visible brightness reaching your eyes. In SAD lamp shopping, 10,000 lux is commonly used as a benchmark for a stronger morning session.
Why buyers should care
A lamp that reaches 10,000 lux only when your face is extremely close may be much less useful than a lamp that delivers a believable setup at a normal desk distance.
How brands misuse it
Some brands print 10,000 lux in large type while hiding the actual distance. That makes the lamp look clinically strong even if the practical setup is uncomfortable or unrealistic.