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LED FAQ: How Much Light Do I Need?


One of the more challenging factors when deciding what fixture is best for your application is the intensity of the light that is required. How much light do you really need? LED manufacturers use equivalency ratings as a way to start you on the right path. For instance, a 250W metal halide fixture could be replaced by the Jarvis Corp WMFT-250, which is a 55W LED fixture. Or a 100W metal halide could be replaced by the Cree 25W LED wall pack or the WPD Lighting Solution FTWP30, a 30W LED fixture. In many cases the equivalencies assigned by manufacturers can be used as a ball park estimate for the amount of light you are looking to replace.

That being said, there is a more technical way to go about finding the perfect quantity of light for your application. The Lumen Rating, or how much light your eye can perceive from any given light fixture, is a much more effective method for figuring out what is best for your application. 

But be careful, LEDs are measured through source efficiency, meaning the actual amount of light output you get when the fixture is running. Many HID fixture are measured at source capacity, the maximum potential output of that bulb. This will give you a lumen rating that will never be achieved, unless in a perfectly replicated scenario, and inflates other specs and features as well. 

We give a range of the potential of the light as opposed to dictating exact results. For instance, the FTWP30 has an equivalency range of 100W-150W. This will depend on what kind of technology you are currently working with. Much like the variation in LED output and the lumen vs. wattage rating, there is even more variation among the different HID fixtures such as high pressure sodium, metal halide, mercury vapor, incandescent, and others.

In other words, a HPS fixture that is 125Ws could potentially have the same lumen rating as a metal halide fixture that is 100Ws. Furthermore, a LED fixture can have a higher lumen rating than both of those fixtures, but only run at 29Ws. This all comes back to how each different technology uses different internal electrical variations to perform as intended by the manufacturer. 

If you are struggling to find out how much light you need for your application feel free to give us a call at (800) 701-1371 or email us at Our goal is to match you up with the perfect fixture so that you get sufficient lighting to your specifications.


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  • Nick Strauss