to address your other questions, I source parts from cobkits, CDI, mouser and others. LED’s contribute just as much heat as any other light per w in an enclosed area. With any light nearly 100% of the watts used end up being heat eventually but where LEDs shine is that they convert a much larger percentage of the energy used into USABLE light before it is converted back into heat, when it strikes objects, etc. This allows you to use less watts to drive an equal amount of photosynthesis in the plants. Essentially with good LEDs you can use 400w to do about the same amount of ‘work’ that it took 600w of HID or florescent lights to do. This cuts down on costs and temperatures in your growing area. Depending on your climate this can be good or bad, in cool climates sometimes people have to actually heat their growing area when using led to keep the plants happy.
Another area where LED shines is in what they call ‘lumen maintenance’, all bulbs loose efficiency as they age but some do it much faster than others. Traditional HID bulbs and florescent should be replaced annually if they are used a lot because they degrade rather quickly. LEDs on the other hand last much longer, some studies suggest that they will only loose 5% of lumen output every 10 years or so, meaning essentially there is no reason to ever replace bulbs, reducing waste, hassle and $$$ for the consumer. Most cobs are rated at 50,000 hours, but people traditionally drive them softly in non commercial applications, which should greatly extended this, estimated beyond 100,000 hours, which is 11.4 years if ran constantly.