If your area is properly lit you won't see an increase in yield, plants can only absorb so much light and the light source isn't the most important thing as long as you are getting around 600-900 PPFD. These people that said they doubled or tripled their yield must have been terrible growing with HID lights, if i tripled my yield i'd be getting 3 grams per watt i'm pretty sure that's impossible. There is a whole hell of a lot of opinion on this section of the forum, not much to back those opinions up besides bashing and name calling, not much fact or science . You won't see many side by side grow logs of LEDs vs HID lights because usually they don't work out well for the guy who spent 10x more to cover the same area and yields slightly less. Just watch greengene's 1000w hps vs AT600 grow log, he confined his 1000w HPS to a 4x4 to give the AT600 the advantage (a 1000w hps easily covers a 5x5 with the proper reflector) and still yielded a few ounces less with the LEDs than the HPS. If i were looking to get a new light source i'd look into CMH lights, LEDs are just too costly, for what they are, they have zero UV, zero far red, HID lights are still superior.
Look at my last journal. I harvested my hps room one week before my led. Gpw for bothe were documented using the same strains cut from the same mom. Each plant is broken down to its gpw for both.
If you don't yield more , what's the point? Saving 30$ a month in electric? That's like 2 grams of weed. Some people need the heat, it was -10F already this year where i live, my grow room is 68F with all my HPS lights running. Proper ventilation and heat exchange will do wonders for any grow.
I used to say the same thing as a decent size hps grower.
Now, my electric bill is cut in 1/2 & I'm flowering twice as many plants in one room
& am Looking to get a 3# increase in yields.
It's all in my journals. I'm only here to share the truth as most people know. Not to get likes or make friends, although I appreciate the ones I have made.
What you say about hps & MH is true though to an extent. Hps grows bigger buds & promotes the second growth spurt, MH provides them more color, trichs & terps. Hps & MH will provide more plant Vigor, thicker stalks.
But a good color balanced led such as white or enhanced white will come pretty darn close to doing all these things while saving a ton on electricity (in a larger setting) & because the spectrum is much fuller, the bud is frostier w/ higher terps then hps.
So, good led gives higher quality & better gpw (save Electric) while matching or exceeding g/sq'.
These are facts Yoda. I document it all in my journals for everyone to see.
Not to mention I compared them for a year before making the solid switch.