Disclosure of information: I imported my first off the shelves UFO 90W units in Nov 08. By Mid 09, I started to lay out the off the shelf lights to more my specs. That said, here is most of it in a nutshell, but I encourage those that disagree.
If you have nothing and you are thinking about indoor/greenhouse growing. I suggest LED. By time a nice digital ballast, wing, reflectors, decent bulbs, all in all it can be very close to the same price. If the LED lights offer you no trouble, you have about as long as the unit parts hold out. Bulbs should be replaced, some may or many not agree, each two grows.
Heat reduction with LED is less than HID, where say some standard fans to move the air around, a HID system may require more extensive and costly heat removal.
Those with investment already with their HID, CFL or other setups, certainly see that they must lay out money for the LED. This is in most case, the dilemma that starts the controversy with this is better than that and visa versa.
Now, Electricity. Let us use, I no longer sell lights, I have lights to always fulfill PAST customer and warranty. Our Standard 300W, has 300 1W LEDs. Spready evenly throughout the light, it draws 265W from the wall. It has aways been taughted as these 300W units all over, cover the same at a 1000W HPS. No, I have tried to never repeat this. I look at a 300W LED light, equiv more to a 600W HPS. So as you can see, electricty use is less 265W draw vs your 600. There are other considerations, unless you are running off 200 Electrical Panels, the AMPs are more in a HID setup, even with some of the latest Ballasts. So while others have always said 80% electrical savings, sure if they push to a 1000 HID comparison but it cannot cover same area. So 300W LED vs 600W HID, about 66% electrical savings.
Now, from other than the best growers I have seen in places our lights were in co ops and all, your final production with LED lighting, I feel comfortable that the avg home grower will get, if all else equal, about 15% less dry weight. Like the debates with those that say Hydro is better than Soil and so on, that is ones preference. I personally like both, but proper soil, I would rather be a soil taster. So, say just to compare only one comparison, 66% electricity savings vs 15% less final. Money growers, really do not care, they want as much as they can produce, because that is $300-400 a sack for them. I really am only addressing the home guy, 8 plants or less, while both HID and LED are fine, alone or in combination, LED alone will end up producing more per electrical cost.
I just do not have the energy here to debate the 1W over the 2,3, 5 Watt Bulbs. Tried over development and testing, up to 3W. Used to mix 3W and 1W in lights. When you use a 3W say, there are less of them and it is felt the intensity is better. I personally do not agree. I would rather have in the case of our past 300W, to have 300 1W, all wavelength/nanometers spread throughout. At my final designs were 380/430/455/612/630/660/730-40. Prodominately the 430-660 in LEDs. Of course is 300 3W can go in the same light size as the standard 300 case, I would say Absolutely. Point me to one light doing this, heat is just too crazy and electronics burn up. So they spread them out with less LEDs to make approx the same total Ws. The latest cutting edge importers, you tell me. Are 3W bulbs still only being pushed to barely over 2W? 2W bulbs about 1.3/1.4? The 1W pushing .8. Do the math vs the cost these other lights are.
If not using light rails for the lights to slowly travel back and forth in a grow, LED will not penetrate like HID. This is where the misconception is, in a way. You use your HID and if not sog of just keeping them under 18-24 inches, your normal plant may finish up about 3_ more like 4 Foot or higher. Not the way to grow with LED. At budding, I feel saying to have your light no more than 18" from your top cone. Now, again, not the best way to grow with LED. Take out main cola, pinched to two. Top your plants all around as much as you can. Make a little bush, keeping the plants to about, not counting stalk, from cutting off your popcorn bottoms to open up for the penetrating LED light. You will reap more per watt with LED this way. Of course, that Is my opinion, I could be wrong (Dennis Miller)
