Aren’t most light sources (unintuitively) measured by the light output of an equivalent incandescent light source? I certainly don’t expect a light labeled as a “40 watt” using anything close to that.
Grow lights usually draw half of their advertised power, and try to justify it by saying 'equivalent' somewhere on the box next to an asterisk.
Very few grow lights that have ever hit my hands came close to their advertised power rating. One company sold me a 50w, 135w, and 300w light set. the 50w was 45 at the wall, 135 was 75, 300 was 150.
And that's because their thermal designs are utter garbage. They can't run at full power. Most UFO lights are literally bolted to a plate, no fins of any sort, and a fan set blows down on it to cool the LEDs. If you get a rectangular panel, odds are you might get one undersized heat sink that doesn't cover the entire LED array (just the array, not the whole panel)
Most efficiency specs are garbage, too, measured with non-calibrated COTS light meters. I can toss most lights in my integrated sphere and I'll see way different from what is claimed.
Very few companies can actually be trusted. I have yet to find one with 100% honesty.
