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How Many LED Watts Do I Need to Replace my Existing Lighting?




We hear this question all the time. The unfortunate reality is "watts" is the wrong way to shop when you are replacing your existing lighting. You need to be focusing on "lumens". In the world of LED Lighting , a watt is consumed by the LED product and light is produced, that light is called lumens. Some LED products are better at doing that than other products.


So it is important to understand that not all LED products are equal in terms of how efficient they are at converting watts to lumens. In technical terms, we call this lumens/watt.

Here is a practical example - Replacing 400W HID


Our Commercial Retrofits are built to run between 145 and 165 lumens per watt. This means that for every watt consumed, they will produce 145 to 165 lumens.

So our 100W Retrofit kit at 155 lumens per watt produces 15,550 lumens. In contrast, a competitive retrofit product that uses older LED Chips is designed to run at 97 lumens per watt. This competitive Retrofit kit produces slightly over 13,000 lumens but needs 135W to do produce that amount of light.

So clearly watts is a poor gauge to determine what you would use to replace an existing light source. If a customer called both companies and asked "how many watts do I need to replace 400W Metal Halide", we would say 100W, they would say 135W.

How is that customer supposed to make a decision? But even then, our 100W produces more lumens than their 135W product.

So when customers ask us how many 'Watts" do I need to replace an existing light source, we always convert them to lumens.

However, there is one large elephant still left here that we need to talk about. And that is the discussion of efficiency. In the above example, our retrofits produce more light while consuming 35 less watts per unit.

This is important, because this is 35 less watts that you are consuming and paying for on your electricity bill. So efficiency does matter, because it means your electricity bill will be significantly less using the 100W Retrofit kit than our competitors 135W Retrofit kit.

So as with the discussion above, there is a vast difference between LED products being offered on the market today.

Read the specs, and educate yourself on lumens. The less watts you consume saves you money, the more efficient the light is means it will produce more light using less energy than less efficient models.

Should I Buy New fixtures or retrofit my existing Light Fixtures?


This is another interesting question. And over the years, we have seen some pretty interesting answers coming from some of our competitors. Those that sell new fixtures claim new fixtures are the way to go. Those that sell only Retrofit kits claim that retrofitting is the only way to go. Who is the LED Consumer going to believe?

Fortunately, MyLEDLightingGuide sells both new Commercial Lighting Fixtures and hid replacement kits and so we are not biased in helping our customer make this decision. Keep in mind one point as you make your decision. Retrofit Kits are typically less expensive than a brand new fixture because you are not paying for the cost of the fixture. You are also not paying for the disposal of the existing fixture.

We have also heard the stories about how LED performs better in a new fixture than they do if you retrofit an existing fixture. That's an interesting argument. Fortunately, we have had cases where we have sent both new fixtures and retrofits to customers to "test" the different options. Based on our experience, we have not seen evidence where the new fixture "always" performs better or is preferred over the retrofit solution. In more cases than not, the correct LED solution wins because they are the right solution for their needs.

Also, some "new fixture" vendors would like for you to believe that retrofits do not last long or as long as their new fixtures. Some vendors like to claim that all product coming from overseas are cheap and made poorly. Here is what we believe to be true. Our products are currently in their 6th generation of production. They come with a 10 year warranty.
They are built with brand name LED Chips and Drivers.


Here are some points of discussion you should consider if you are debating whether you should retrofit or replace your existing fixtures.

If your fixtures are in relatively good shape, retrofitting is typically lower cost, all things considered. New fixtures are not cheap, and using your existing fixture will save you money, plus a Retrofit kit is less expensive to ship than a new fixture.

  • If you have a large investment in your LED Light fixtures, then retrofitting allows you to keep your fixtures but move over to the new technology. A good example of this is area lighting at car dealerships where the pole and light head are an architecturally matching pair. Replacing the head with a non-match led head does not make sense.
  • If your fixtures are old and deteriorating, then you should replace your fixtures. Our Retrofits are not water proof, and you could damage them if they get wet. The LED Drivers are typically waterproof (look for the IP rating on the label, it needs to say IP65, IP66 or IP67).
  • There are instances where we would always recommend new fixtures over retrofit. One instance would be for High Masts and most 1000W Metal Halide High Bay applications.
  • It takes slightly longer to retrofit a fixture than it does to replace it.
  • You have to account for the disposal of the bulb, ballast and fixture when you replace a fixture and account for the disposal of the bulb and ballast when you retrofit a fixture.
  • Retrofit solutions perform as well as new fixture solutions.
  • Retrofit solutions will last as long as new fixtures as long as the Retrofit kit is installed properly.
  • Regardless of what solution you choose, you need to review the specifications of the LED components.
  • You should always determine how many lumens you need to replace your existing fixture, NEVER purchase based on watts. Not all LED solutions produce the same lumen per watt output.
  • Pay special attention to the lumens per watt of a fixture. IT DOES MATTER. A LED product at 135 lumens/watt will consume far less energy than a LED product producing 97 lumens/watt. Not all LED solutions are the same. (remember, always buy on the lumens you need, never on the watts you think you need.)
  • To calculate lumens per watt, take the total number of lumens a product produces and divide it by the watts it consumes.


Some Lumen Guidelines to Follow


For indoor fixtures


250W HID 10,000 - 14,000 LED Lumens
400W HID 15,000 - 25,000 LED Lumens
1000W HID 38,000+ LED Lumens

For outdoor fixtures



250W HID 7,000 to 10,000 LED Lumens
400W HID 12,000 to 16,000 LED Lumens
1000W HID 38,000+ LED Lumens

  • Our most powerful Retrofit kit produces over 50,000 lumens, our most powerful new fixture produces over 117,000 lumens.
  • We have new LED Lighting fixtures that can replace from 100-1000W HID, we have retrofits that can replace from 100-1000W HID.
  • Pay special attention to the lumens per watt of the LED fixture or retrofit. IT DOES MATTER. A LED product at 150 lumens/watt will consume far less energy than a LED product producing 97 lumens/watt. Not all LED are the same. (remember, always buy on the lumens you need, never on the watts you think you need.)
  • To calculate lumens per watt, take the total number of lumens a product produces and divide it by the watts it consumes.
  • You can get rebates for both new fixtures and Retrofit kits. Make sure they are DLC Qualified. That is the key to getting rebates with your utility company. You can check if a product is DLC Qualified on the DesignLights Consortium website. DLC has rebates for LED Lights.
  • Rebates with DLC Premium should be higher than rebates with DLC Standard. Your utility company is typically who provides the rebates and sets the rebate amounts.  Check their website.
  • All DLC Products are warrantied for at least 5 years.
  • All our LED Fixtures and Retrofit Lighting are either UL Listed or ETL Listed.
  • Replacing the light parts of an existing fixture with the a Retrofit unit will not void the UL/ETL Listing of the fixture.
  • ETL Listing is the same as UL Listing. They perform the same test, and the certification is the same. The only difference is that the company who performs the test.

The Truth About LED Lumens


Why is it you can replace some lights with more 'advertised' lumens with a LED light with less lumens. Here are 4 reasons why you can use less LED lumens to replace traditional HID lights

1. Focused Directional Lumens


LED light is directional, conventional light sources are omni-directional and require reflectors to gather the light and focus it to where it is needed. Any reflection that is over 1 bounce effectively loses the effect of the lumen. It has been proven that you can lose up to 30% of the effective lumens in this process.

2. Quality of Lumens


This is related to Color Rendering Index, or CRI, and the best explanation is seeing how much better you can see when comparing LED to High Pressure Sodium. It is not uncommon to have customers tell you that 20,000 lumens of LED appear brighter than 60,000 lumens of HPS. The basic truth is you need less quantity when you have higher quality.

3. Photopic and Scotopic Lumens


This has to do with how a camera perceives lumens and how humans perceive lumens. Photopic lumens are lumens that are detected by a device that is similar to a camera. Light meters register photopic lumens.  Scotopic lumens are lumens detected by the human eye. LED produces light within these spectrum's, which means the light perceived by LED is light that we use. It is rare to see a LED light produce IP or UV spectrum. These wavelengths are invisible to people, so they have no value to us from a vision perspective.

The science of scotopic lumens is associated with a factor that allows us to adjust the photopic value to give a true representation of how useful the lumens are. The factor, developed by scientists, is an attempt to level the playing field. The factor is used to adjust the effective value of the lumen, either up or down from the advertised photopic lumen advertised on the package. Some lights, like HPS, have a factor that reduces the lumen amount. LED, on the other hand, typically has a factor > 1.7, which means the lumens it is producing is far more effective to us. Therefore, less lumens is required to do the job.

4. Lumen Degradation


It is not uncommon for HID bulbs to have lost up to 50% of its initial lumens after only 5000 hours of life. Yet these bulbs are rated for 20000 hours. That means the customer is using a bulb that is performing poorly for the next 15000 hours of life. As well, as lumens degrade, so does CRI. And so the "effective lumens" of the light is dropping quickly.

We have been very successful replacing 400W Metal Halide bulbs with our 100W LED Bulb Replacement Kit. The comments we here back is the light is brighter and the area is brighter. It currently produces 15,500 lumens.

Another example is 100W LED LowBay producing 14,000 lumens. This is designed to replace upwards of 400W metal halide. If you have a low bay fixture filled with CFL bulbs or a 250W Metal Halide bulb, this light is going to be a dramatic improvement over what you have. And we have models in either black or white, so it can easily fit into any decor. We can add opaque lenses to hide the LEDs, if that is what you are looking for. L70 life hours exceed 50,000 hrs, compare that to a Metal Halide bulb that is at L50



MyLEDLightingGuide has been in the business of educating and selling LED Lighting since 2008. If you have any questions about our products or LED in general, feel free to contact us or call us at (888) 423-3191


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