I work from home in an area that gets high amounts of fog, and I frequently go days without seeing the sun. I can confirm that I seemed to need about 10k lumen

I work from home in an area that gets high amounts of fog, and I frequently go days without seeing the sun. I can confirm that I seemed to need about 10k lumens before making an noticeable change in mood. I used three (1 warm, 2 cold) relatively inexpensive 36W LED bulbs from ebay locally - http://www.ebay.com.au/itm/121704759594 http://www.ebay.com.au/itm/121704759594 (Note they are LARGE and require a free-standing light fixture without any type of lampshade)