Understanding LED Light Output And How To Avoid Being Misled With False Wattage Claims

We've seen a concerning trend in LED grow lighting which revolves around the promotion of false and misleading lamp wattage. This is important to indoor growers because the amount of photosynthetic light output a lamp produces is limited by the amount of wattage the unit draws from the wall. Lower light output levels will affect crop yield, potency and flavor profiles. 

Here is an example of one of many products advertised online with a misleading claim of total wattage. We've circled the claimed wattage, and in the description of the product the admission of actual wattage which is not always very obvious to spot.
 

 

Advertisement with Misleading Claims

 

It's actual wattage is 330 watts. However it advertised as a 1200 watt grow light. That is a 300% inflation of actual light production output which is very misleading. 

LED diodes output visible light energy in lumens or luminous flux. Each diode is supplied incoming voltage which is distributed to the diodes as a portion of the total amount of wattage the unit draws from the wall. Each LED light is limited to a specific maximum wall draw based on the voltage supplied to the Driver / Power Supply Unit. It varies slightly if the light is wired to accept 110/220/277 volts. But the variance is small as compared to the lamps wattage wall power draw. 

Many of the products with inflated wattage claims also lack information on photosynthetic light output. The total amount of photosynthetic light being created is measured in a lab using a machine called an Integrating Sphere. The sphere measures total luminous flux output which can be translated to Photosynthetic Photon Flux or PPF. Nearly every manufacture or lighting worldwide owns an Integrating Sphere, and in order to secure UL or ETL safety ratings these products are also sent to third party labs who use a sphere to test the total light output versus energy consumed. We suggest that consumers buying LED lighting for indoor growing ask the supplier how much PPF the light is producing. This is important information needed to do side-by-side comparisons between grow lights. There are a lot of variables to consider when buying a grow light but at a minimum, the total amount of watts being consumed by the light (power draw at the wall) and the total amount of photosynthetic light (PPF) being created is important.

An easy test for LEDs verifying actual watts being used is to buy a product like the Kill A Watt. Simply plug the light into the Kill A Watt meter and it will display several power and energy consumption variables including watts being drawn from the wall. The light advertised above would theoretically show a power draw of 330 watts. Assuming that claim is true. These can be purchased for less than $20 online. 

 

Kill A Watt power meter

 

Indoor growers will benefit from more truthful comparisons when making decisions to buy LED grow lights to maximize their crop success. 

 


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