How do I know which LED fixture/bulb will accurately substitute for my conventional lighting product?

The short answer is "let us help you."  There are several things to consider while attempting to understand if an LED product will be an appropriate substitute for your conventional lighting product, whether that product be an incandescent, fluorescent, or HID.  Where applicable throughout the BrightWay website, we have tried to include a reference guide comparing our LED products to popular conventional light sources of similar brightness.


The lighting industry has traditionally associated the light output of a light source (bulb or tube) in terms of the WATTAGE consumed as opposed to the LUMENS emitted.  In other words, the industry has partaken in a little bit of a misnomer.  Lumens are an actual measure of light output, whereas wattage is simply a measure of power drawn.  Due to the fact that LED products are typically much more efficient at converting electrical energy into light energy, LED lighting products are being appropriately labeled with both a wattage and a light output.  However, it can still be difficult to compare LED lighting with conventional products because many of the conventional products still don't bare a label that discloses the luminous output.  This creates a tough situation for consumers trying to evaluate an LED light source with the less efficient conventional lighting technologies.

Light at the Source vs. Delivered Light

Yet another aspect of lighting that can cause confusion is the difference between Lumens (the amount of illumination at the source of the light) and Footcandles or Lux (a measure of illumination delivered to a surface or point).  The reason why this makes things a little bit difficult to compare conventional lighting technologies to LED lighting is that LED products are lensed to distribute light in a more directional fashion. 

For example, a metal halide (MH) bulb is placed into a parking lot fixture which is meant to throw light downward in a 180 degree distribution.  The MH bulb is emitting approximately 18,000 lumens and is doing so in all directions, with the fixture attempting to reflect light back out and deliver it to the pavement below.  Whereas an LED fixture that is emitting around 12,000 lumens at the source is lensed in a manner such that it is distributing all of that light directly out of the fixture, no reflection, and as such can often deliver as much light to the surface in a more even fashion than its MH counterpart.  In other words, when less lumens are distributed more efficiently from the light source, it is possible that they can yield more footcandles (or lux) delivered to the active surface – which tends to be what most applications require and/or desire.  This is a big reason why lighting designers might model up a photometric layout of a room/space in computer aided design software – to help them understand how much light is being delivered and where it is being delivered to.

Varying Efficacy of LED Products

There are lots of LED manufactures making lighting products and many of those products have varying efficiencies of LEDs inside them.  As such, it is currently rather difficult for any organization in the LED industry to publish a generic “LED Conversion” document for ALL LED products which states that a particular LED wattage should adequately replace ALL conventional light products of a particular wattage – irrespective of manufacture.  An example statement, “most 35W LED wall packs should replace most 175W Metal Halide wall packs.”  This very issue is what makes it difficult for energy providers and utilities to devise generic prescriptive rebate programs for retrofitting to the more efficient LED lighting products.

Light Degradation

Conventional lighting technologies tend to degrade in light output much faster than LED lighting.  So, if you have a conventional lighting solution that is a couple of years old, there is a good chance that it could be 30-40% less illuminant than when it was first installed. This means that the existing conventional lighting solution could be much less bright than a new version of the same solution – to which a new LED product might be compared.  It is important to understand if your existing light levels are sufficient and to consider if you’d prefer more or less light in the space being considered for retrofit.  Depending on the application, there could be an opportunity to not only reduce the power consumption per fixture by switching to LED lighting, but also to reduce the number of fixtures needed in order to provide a comparable level of illumination.