|MLA Citation:||Bloomfield, Louis A. "Question 387"|
How Everything Works 21 Apr 2018. 21 Apr 2018 <http://howeverythingworks.org/print1.php?QNum=387>.
The optimal internal temperature for a fluorescent lamp is about 60° C (140° F). The tube reaches this internal temperature when its outside is about 40° C (104° F). When the surrounding temperature exceeds 40° C, the tube begins to waste energy again because the density of mercury atoms in the vapor becomes too large.