LED 2 x 4 foot troffers equivalent T 8

[Stevenfyeager]

How can these 2 x4 foot 4900 lumen troffers be equivalent to the 4 foot, 4 foot bulb fluorescent bulb fixtures if each T 8 bulb is 2900 lumens? ( Nicor product) I just want to
make sure my sore customer will be happy with changing T 8 troffers to LED fixtures. Thank you.

 

[Stevenfyeager]

("store" customer). sorry

 

[steve66]

2900 lumens is the output of each lamp, but the fixture will loose some of that light.

You are comparing that to the output of the fixture with the LED.

Also, I believe something about the output of LED makes it seem brighter than it is.

 

[mpoulton]

Gotta check the photometric data for the two fixtures to see if the LED is a decent replacement. It's the total lumens out of the fixture that counts, and the distribution of that light (angle) matters too.

 

[JFletcher]

LED lights are more directional than fluorescent. Brightness is in K; they're probably 4100K bulbs and may have a higher CRI than fluorescents.

Sore customer. Funny typo!

 

[GoldDigger]

LED lights are more directional than fluorescent. Brightness is in K; they're probably 4100K bulbs and may have a higher CRI than fluorescents.

Sore customer. Funny typo!

Actually, color temperature is in K. That is the general tendency of the light color from red to yellow to white to blue.
It is a reference to the temperature of a hot filament (actually a black body radiator) that gives the same visual effect.
It is generally true that for the same amount of radiated energy in the visible range you can see better when the color temperature is higher. You may not like the effect, but you can see better.

Independent of the overall warmth bias, the Color Rendering Index (CRI) gives an indication of how well the light allows you to see the same gradations of color that you see under tungsten incandescent light of the same color temperature.

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