im sure this has been discussed. i want to bring up a point about heat. some one correct me if they can. the only way to actually get less heat with led's is to use less watts. in other words if i replace 1000 watt hps with 1000 watt led i will get the same amount of heat. in fact you can apply this to incandescent, halide, a washer machine, computer, refrigerater, tv etc... in a closed system all forms of energy whether kinetic chemical or electomagnetic eventually turn into heat. leds are cool to the touch but put out heat in the back end with heat sinks and fans. i was wondering why my ambiant temps have not been dropping. thought there is something to be said about lower thermal radiance which is ir. this is what makes hid so intense that it burns leaves. led on the other hand has heat in the form of convection and conduction i.e. fans and heat sink. so its the same heat just more diffuse. but now hps is can be air cooled where leds cant or in a sealed room there is no way to air cool without loosing co2. so the ambiant temps will be higher with leds. im perplexed. see this is what happens when marketing confounds the consumer. i got the physics on my side though. i think. I would love to hear more info please.