# LEDs - Do Lumens count?



## jw0445 (Oct 9, 2009)

That's impressive. Thanks for sharing.


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## 99cents (Aug 20, 2012)

Where did you get the photos, Dave? That's not PN in October. 

All I can think of is lumen depreciation. You're going to lose half your punch, probably more, over the life of the MH lamp. Combine that with a dirty old milky lens and the old fixture isn't very efficient.

The lumens difference with LED is still something I'm trying to wrap my brain around, though.


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## drewsserviceco (Aug 1, 2014)

Just my shot in the dark:

It's related to the lights actual wavelength (I think) where the HID lighting is a more diffuse wave so you're losing lumens as you get further away from the fixture where LED is a more focused wave and will penetrate further....
...so you can do more with less. 

Thanks for the side by side comparison.


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## daveEM (Nov 18, 2012)

99cents said:


> Where did you get the photos, Dave?


You must live on the wrong side of PN . Here in the West End we bask in sunshine and all things are great. 

1st. pic I took at 7AM on October 19, 2016. 

2nd. pic yesterday October 20, 2016 at 7AM give or take a minute. 

I'm efficient eh? Usually I'm looking for stuff to do starting around 3AM but didn't want to risk arrest by taking the pic then. Married a long time arrest is also possible if I try anything with the other half. :jester:

I've been looking after the place about 5 years now. The bulb would be at least 2 pushing closer to 3 years old. The lens dirty for sure. The old fixture does have a hood on it blocking light from going straight up. Light can go out and down...

*Note*: The pic below is a Look-Alike type I installed a couple of years ago when that lens broke. The MH fixtures looks the same except they are about 4 inches deeper (room for the ballast).


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## daveEM (Nov 18, 2012)

drewsserviceco said:


> Just my shot in the dark:
> 
> It's related to the lights actual wavelength (I think) where the HID lighting is a more diffuse wave so you're losing lumens as you get further away from the fixture where LED is a more focused wave and will penetrate further....
> ...so you can do more with less.
> ...


They do say on their website (in the link 1st post)...



> The new 18 Watt LPACK is designed with next generation LED chips and phosphor, *precision engineered optics* and super high efficiency driver.


Good stuff this technology.


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## drewsserviceco (Aug 1, 2014)

I agree with you on the optics, but I was referencing the actual wavelength of light that is being produced. 

I noticed this most when doing a retrofit in a dirty old warehouse. 

As I looked down the long aisles, the area that still had the existing lighting was more "ambient". It looked like the air space between the fixtures and the floor was more illuminated. 

The area using the LED lighting, as you looked down the aisle, that same air space looked dimmer, but all the surfaces were brighter. 

Kinda rambling, but hopefully I'm getting the idea across. 👍


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## 99cents (Aug 20, 2012)

daveEM said:


> You must live on the wrong side of PN . Here in the West End we bask in sunshine and all things are great.


Yeah, I'm just a south side schlep. The only green grass we have over here is that cheap indoor/outdoor carpet left over from the 70's  .


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## MikeFL (Apr 16, 2016)

Very cool post DaveEM.
Thanks.
It looks like that turned out real well.


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