A watt is a watt 600w will produce the same amount of heat no matter what the source is. If you get a genuine quantum board hlg will replace anything that's breaks saving you that $15-$30.
First lets start with this...."Physics 101 for dumbasses"
A Watt is a unit of power, defined as the rate of energy transferred [per second]. The energy is usually defined as Joules; therefore, one Joule per second is one Watt.
When measuring heating effects, a unit of thermal energy known as a calorie is used. One calorie is 4.184 Joules.
Materials have a property called thermal capacity or specific heat. This is a measure of how many calories are needed to raise 1.0 gram of the material one degree Centigrade. The thermal capacity of water at 15 deg. C is 1.0 calorie. That is 4.184 Joules or 4.184 Watt-seconds. The entire energy could be transferred to the water in one millisecond at a rate of 4184 watts to produce the same temperature rise of one deg. C.
The thermal capacity of materials changes slightly with temperature primarily due to changes in density, and very dramatically at phase transitions, such as ice melting and water boiling.
So this means that an HID with an aluminium reflector will generate different heat than the same watt light with a steel reflector.
Now to the lighting power factor (and yes this is cut and paste from skoomd1 on Reddit.
600w 6x Vero 29 cob array
Here is the spectrum, which is extremely close to the sun which plants grow their best under PERIOD. No stretchy, leggy plants like with HPS, increased potency and smell in buds, and pheno colors will just pop out every time.
-Color temperature of 3500k
-80 CRI (closeness to sun with 100 being identical, over 50 CRI is high for growing and means your plants will express their phenotype fully and be more potent)
-937 PPFD covering a 4x4 space (600-1000 is optimal, ppfd is PAR averaged over a given space))
-1396 PPF
-49% efficiency
-2.33μmol/J efficiency/par output (Quantum boards are 2.8 at same power and go as high as 3, CXB3590s at 50w is around 2.6-2.7μmol/J)
-Outputs 294 PAR Watts, and 306 Watts of heat (wasted energy)
-No hotspots, every point over a 4x4 space would be
600w HPS Eye Hortilux bulb (the best on the market) in any decent reflector/ballast combo
Here's the spectrum which is nearly all green and yellow light, which is still in the PAR range so 1 par W of hps = 1 par w of COB, but the plants can hardly make good use of those wavelengths versus the Chloraphyll A/B spikes in the blue/red wavelengths, like you see on the COB's spectrum.
-Color temperature of 2100k
-25 CRI (hence the disgusting inefficient yellow/orange light and the TERRIBLe stretching hps causes)
-671 PPFD over a 4x4 space (600-1000 is optimal)
-999 PPF (how much PAR it outputs per second)
-22% Efficiency (some lamps can go up to 30%on paper but its rare to actually see due to differences in ballasts and wattages between individual setups)
-1.65μmol/J raw par output
-Outputs 150 PAR Watts and outputs 450 Watts as wasted heat
-Very uneven light coverage, you have a large hotspot in and around the middle of the canopy, and will VERY rapidly drop off around the edges to very low levels.
So if you want to mimic the same PPF of a 600w HPS, then you could reduce your wattage on the LED to both energy cost and extra heat produced, and still yet get better performance.
Oh and if one lived in the US and could take advantage of HLG free replacement program, then one should take advantage of that. But for those that live outside the US, unfortunately the postage for the return would be the same cost as me jumping out and buying a Cree, Citizen, or Vero COB. If you read my post thoroughly and not just read what you wanted to create an arguement over, you will see that I do like QB as they produce nearly on the same product as a COB (obviously dependant on Kelvin, watt for watt, etc etc) but have the added bonus of a more evenly spread light distribution. I have both, and as I said only prefer the COB for accessability to replacement for the cost
