Yip, thats why i wrote that two of the hc4's would equal 400w, the same as the hps that is referenced, and the two of them combined would give out less light than the hps!
Again this just shows the variables between lights of the same power usage.
The link you posted shows the difference between two specific products so cant realy be used to answer such a generalized question.
Air cooled reflectors deal with most heat issues nowadays, granted the heat produced is just wasted energy but grow area temperatures due to lights are almost a thing of the past regardless of which lighting option you chose!
So in conclusion the question is almost unanswerable unless you are talking about two specific products.✌
Which is why I asked him what he thought an "average" DIY cob build would be!!
Christ, this is like pulling teeth. We KNOW that assorted premade LED lights have such a variance in capabilities it is beyond belief, but this was a question over a traditional HPS vs COB when the "person concerned" could not even define what he meant by an "average" COB build.
Now, as stated, an HPS with a MAGNETIC ballast, not ELECTRONIC, produces circa 0.9 µmol/w which is less than the HC4.
With me so far? Good.
Then an ACTUAL comparison, and you can read exactly what they used, proved that similar wattage over a defined coverage gave a 131% increase in µmol/w when wattage and actual footprint was equal when using CObs. That one does not need Einstein to figure out, does it.
But, like the previous person, you are ignoring the VERY important link that gives you the factual data showing the difference and are quibbling over minor details which ignore the bottom line of the "other person's" declared definition regarding µmol/w and how even the HC4 produces MORE µmol/w when compared to an HPS with a magnetic ballast.
Now, and I'm sorry for the language used, if fuckwits cannot even define the parameters they want to use for comparison, even when asked to do so, then you will get multiple examples regarding the one, dodgy, figure he used.
The data is clear, it has been explained, and, once more, if you think that LED is somehow less efficient than HID despite so much less energy being converted to pure heat I would like to see the REAL data proving that, for I have provided a clear example of how, watt for watt, COB's can produce 131% more µmol/w, which was the figure he wanted.
You want to prove that wrong, be my guest.