cfls are hot too, you just get to spread the heat out more so it's not so concentrated. That many watts of cfl is going to be hot unless you have a large space. the hps with an air cooled hood would run cooler and produce better results imo. i used to use a t5/cfl combo that equalled 420 watts (haha) for flower and it got damn hot. easily hit 100 if i left the door shut for 10 minutes. Now i have a 400w hps, fewer fans and on the hottest day this year so far the temps only hit 92 with the door shut for 10 minutes. (i sometimes have to shut the door but i never leave it that way) My overall temps are much easier to control, so not only am i saving on power for lights, Im saving on fan usage too. Plus now i can use the t5s for veg and get a perpetual grow going. basically it's all about how the light is distrubuted with cfls, and the way they need to be arranged for optimum results makes the space very hot.