I've been scratching my head about why people often seem to find that CFL doesn't yield as well as other lighting sources e.g. HPS, as peoples' usual explanations about light not penetrating etc etc don't make much sense to me. Well, I've been trying a CFL grow and I think I have a pretty good answer for everybody now: I bought two types of CFL lights: ones which were advertised as 30W and ones which were advertised as 105W (that's real watts, not equivalent watts). They didn't seem that bright to me so, feeling a bit suspicious, I spent a tenner on a nice german power meter. That told me that the 30W CFLs were actually drawing 25W each, which is not great. But far worse was the larger lights explicitly advertised as grow bulbs. They came out as 41W each rather than the advertised 105W! That's not even half!

Consequently, my CFL grow which should have been running on a total of 300W real power has actually been getting a measly 157W! My calculations were based on getting about 18 to 20 thousand lumens, but in fact I've probably been getting more like 9 or 10 thousand.

In my opinion a CFL grow should be the match of HPS watt for watt (maybe a little in HPS favour), so I should have been about comparable with a ~200W HPS setup. If I'd not done these measurements I would have been scratching my head why I only got half the yield compared with a 200W HPS setup and would probably have concluded that, for whatever reason, CFL is just not as good for growing cannabis.

Has anybody else tried measuring the power consumption of their lighting setups, especially those based on CFL? I've a feeling that many grow lights in particular, which are often made by smaller companies many from china with no reputation to go before them, really have light outputs far far less than those that are stated.
Powernoob Reviewed by Powernoob on . Theory about why CFLs don't work as well as HPS etc I've been scratching my head about why people often seem to find that CFL doesn't yield as well as other lighting sources e.g. HPS, as peoples' usual explanations about light not penetrating etc etc don't make much sense to me. Well, I've been trying a CFL grow and I think I have a pretty good answer for everybody now: I bought two types of CFL lights: ones which were advertised as 30W and ones which were advertised as 105W (that's real watts, not equivalent watts). They didn't seem that bright Rating: 5