Hello, I'm new here. I was wondering if anyone could help me out with some confusion regarding units. My landlady (like most people) wants to save money on power consumption, so she has me installing Compact Fluorescent Lightbulbs(CFLs), which are supposed to save energy. On the package, it said that a 15W CFL is just as good as a 60W incandescent bulb, because they both give off ~800lumens. I couldn't understand that. The lumen is one of the three units whose meanings I don't remember: candela lumen lux Also,I found out that they measure the physical quantities luminous flux, illuminance, and intesity, but I don't know which measures which, and what the defn's of these are. Can anyone help me out?