What is the difference between "LED Watts" and "True Watts"?
LED diodes are rated based on the amount of power (wattage) they can theoretically handle, if they are perfectly cooled. Some LED grow light companies advertise their lights based on this theoretical wattage- we call it "LED watts". However, excessive heat generated by running LEDs at this theoretical maximum causes LEDs to degrade ("burn out") and makes them shift the color of light they are giving off, so in the real world LEDs are never run at their full rated wattage. This means that "LED Watts" is a completely useless number for comparing the light output from two different lights-- for example, you can have two "500 LED Watt" lights, with one running 100 watts of actual power through the LEDs, and the other running 300 watts of actual power.
Many companies selling LED grow lights only use the "LED watts" to advertise their lights, as the number is always larger and more impressive than the actual power draw, but it really tells you nothing about how much wattage is actually being used to produce light. The only reason we include LED light watts on our website is because so many people request it as a means of comparison (for which it is completely useless-- true wattage is the most accurate means of comparing relative power of any plant grow light).