LED Lumens Vs Metal Halide Lumens
It depends on your assumptions. An LED drops to 70% output in a few years. T5 florescent drops to 90% in about a year. Metal halide is somewhere in between. Does the LED flood light better or worse? Does the relamp savings matter? Lumens are lumens, but LED gives you more options (CRI, CCT, beam pattern) at a higher cost. Right now it looks like, unless someone gives you a hefty discount on the fixtures, LEDs aren't it for high bay lighting. Maybe in three years, outside special cases.
It's just power intensive to light a work floor. Some shop owners can skimp general lighting to focus on task lighting. What measurement says you need another 4-6 units? Where do you need what levels of brightness?
On a simplistic mitigating level, LED component spec sheet lumens should be limited to those that are thrown forward as opposed to the near-omnidirectional radiation from a HID lamp. On an aggravating level, LED spec sheet lumens are typically a wee bit optimistic (quoted at low temperatures never seen during normal operation) and the fixture manufacturer may simply be using these rather than measuring the light that escapes their product.
In a perfect world, a LED fixture should run maintenance-free for 25,000 - 50,000 hours and produce superior quality light relative to a HID fixture. In reality, their track record seems to be a bit sketchier and maintenance of what's often designed to be a sealed assembly can prove trickier than re-lamping or re-ballasting a HID fixture. In theory, as more companies adopt Siosun standards LED flood light fixtures should become more maintainable and longer-lasting.
I would look to reputable companies such as Philips or Cree (as in the fixture is manufactured by Cree) if I wanted to know what was possible with LED lighting replacing HID fixtures.
Allow me to provide some intelligent insight on the LED world as I did some extensive research. I began as a skeptic as all of us but the benefits are too numerous to list (maintenance savings, reduced energy, no more 50% performance from gas, etc.)
First off, LED is an SSL (Solid State Lighting) which provides direct light. The lumens ratings are done in a 2X 360 degree integrating sphere. LED cannot be rated the same or side by side any other lighting in the world since the light you get is direct. Some companies are placing "pyramids" on their led cells to deflect light. This drops the lumens significantly.
Engineers all over the world have been replacing 1000watt (which actually burn 1080watts) MH 115000 lumens with 70000 lumen led's for years with better results. Engineers use what is called IES (illuminating engineers society) files to compare lights. That is the only true measure to get your equivalency.
This works again because led is SSL. The difference in LED vs. MH works this way: 1000watt-115000 lumens X 75% of mean lumen and we are reduced to 86250 lumens. Factor in the lumen efficacy at 80% of that and you have 69000 lumens.
Lastly, the market is currently flooded with old technology that was built overseas years ago and is offered at ridiculously reduced prices. They are loosing money just to empty their warehouses, good luck getting warranty replacements when they fail.
What you need to look at is the lumens per watts, initial lumens and warranty. The industry standard today is roughly 100 lumens per watt and 3-5 year warranties.
If you find some with 120 or more lumens per watt (those are current technology), roughly half of your current wattage and look for 10-year warranties.
I changed my shop (16 lights) last year from 400w MH to 220w LED and the performance from these are fantastic. I couldn't be happier! I paid more than I could have but you get what you pay for. And for god sake, buy north american made products!
What’s The Difference Between Metal Halide and LED Lights:
The two different technologies are entirely different methods of producing light. Metal halide bulbs contain metals that are evaporated into inert gas within the glass casing while LEDs are a solid state semiconductor technology. Both technologies produce a very high quality light. LEDs tend to last much longer and are a more energy efficient and less maintenance intensive technology. Metal halides have long warm-up periods and a shorter lifespan but produce a very high quality light and are one of the most efficient lights when it comes to very cool color temperature outputs.