hey guy, as a fellow CFL'er i thought i'd take a stab at answering your questions.
in answer to your first question, CFL's actually run hotter than HID, watt
for watt, the advantage is that the heat is spread throughout the grow
room rather than concentrated at one very hot point.
because it's spread out, it's easier to deal with.
also, 2 - 3 inches from the plants is a good rule of thumb, not 1 - 2 cm's.
LED's are Light Emitting Diode's and they're way more efficient than either
CFL's or HID's, unfortunately, they're still very new technology so they are
still working on them.
a few more years and and we'll all be using them, go take a look at these threads
if you're interested in LED's
http://boards.cannabis.com/grow-log/...-grow-log.html
http://boards.cannabis.com/indoor-li...row-light.html