In order to boost efficiency you can do a few things differently but get similar results:
- use more efficient whites (hlg uses the new evo chip, very short supply of these apparently, only seen them with hlg and invisible sun)
- use more white diodes per watt (hlg have higher diode count than chilled)
- use more efficient reds (not 100% sure which one is the winner here, osram square versus samsung lm351)
- Use more red diodes per watt of added red (chilled wins here with 45 versus 2x18 for the 2 hlg boards)
But for me in this question the main thing is spectrum:
Chilled v3:
View attachment 5030090
New hlg diablo:
View attachment 5030091
Pretty similar, chilled got a bit more red, hlg got a wider blue peak. So same-sies? Hard to say but from what ive seen from growers adding extra blue/violet it is to prefer as it adds to a fuller spectrum in a especially important part of the spectrum. Better coverage in the 430-450nm of the spectrum, to me its preferable than adding even more 660 red. This blue region both covers a chlorophyll peak and a peak in the stomata aperture action spectrum: it should help your plant drink more water/nutes and help you avoid some of the problems with growing with leds. Adding even more reds: its fairly easy to overdo on 660 reds and get a spectrum that gets a hard time to work well, especially when using high intensity. So for me on efficiency and spectrum the hlg wins. But chilled wins on form factor: being a bar light it is likely better at delivering the light to the cannopy instead of losing light to walls and hanging height. RN my vote would be hlg. It would also support changing tent size to 2x 2x2 or even a 3x3 if things change in the future. As well as the warranty issues raised before. Best of luck.
Ps: the light that hasnt been mentioned is
@Grow Lights Australia s 420 Highlight board: its got great efficiency and an even better spectrum than both lights mentioned but you would pay maybe a bit more and have to do a bit of very basic diy. But it adds violet/uv all the way down to 400nm, loads of 660 red but also far red (730nm) which works together in tandem with 660 reds. If youre looking for a light that has it all this should be considered.