Lighting How many cfl actual watts will i need per auto??

[droskee420]

...i have done alot of research on the autos,cfls etc..cant seem to get the hard info i need. the grow room will be 3x2x6 HPS is not an option because of heat and financial status.
loving this forum...hope it keeps on keepin on....thanks everyone

 

[Egzoset]

Hi,

I'd like to see an answer on what has been asked in your title as well.

All i can tell is that you can't win on all aspects of the trade-offs you need to make. It takes a lot of CFLs to equal the flux of a single HPS lamp, so much that i doubt this would be economically viable in the end if cost were the only parameter to consider. Alternately, no HPS lamps is faint enough to compete with CFLs when it comes to remaining relatively cool, IMHO.

My guess is "Trade-Off" would be the master key-word here, it's possible to optimize your selection but there are limits.

You can start with a few lamps for young plants and these will be happy but a time will come when it will be necessary to add many more lamps, which is what i'd like to read about as well...

 

[ripster]

Here's what I found:

Do not use watts when calculating the light output. Watts represents how much power is being used, not how much light is being generated. For example, it takes 100 watts for an incandescent bulb to generate about 1,600 lumens, but it only takes between 23 and 30 watts for a compact fluorescent bulb to generate the same amount of light.

lumens; a 23w compact fluorescent emits about 1600 lumens.


Dimensions: 4 ft x 3 ft = 12 sq ft
Requires: 75 footcandles or 75 Lumens/square foot


This room needs 75 lumens per square foot, therefore:



900 lumens required in the area



Incandescent Requirement:



Using the 900 lumen requirement:



900 lumen / (1690 lumen/ bulb) = .53 bulbs



Therefore we need 1 incandescent bulb ( rounded from .53) to meet the lumen/fc needs for this area.



Compact Fluorescent Requirement:

---------- Post added 11-29-2011 at 01:04 PM ----------

Compact Fluorescent Requirement:



Using the 900 lumen requirement:



900 lumen / (1750 lumen/ bulb) = .51 bulbs



Therefore we need 1 Compact Fluorescent bulb (rounded from .51) to meet the lumen/fc needs for this area.

 

[jiml74]

Ripster my box is 13.5 sq feet. 13.5 x 75 lumes per sq feet is 1012 lumes. Im running two 65 watt at 3900 lumes each and two 42 watt at 2600 lumes each, for a total of 13,000 lumes. I can fit a few more lights in the box, but would it just be over kill. Can I have to much light?

 

[ripster]

Ripster my box is 13.5 sq feet. 13.5 x 75 lumes per sq feet is 1012 lumes. Im running two 65 watt at 3900 lumes each and two 42 watt at 2600 lumes each, for a total of 13,000 lumes. I can fit a few more lights in the box, but would it just be over kill. Can I have to much light?

Maybe you mean your box is 36 cubic feet? But square feet, it's 6. Length x width = square feet. And Length x Width x Height = Cubic Feet..:thumbs:

Anyway, you have plenty of light there dude. One more wound hurt a thing...

@jiml74
OOPS.. your not the original poster of the thread. Sorry. Thought I was talking to droskee420. You can have to much light, but yours sounds fine. Just watch for any white dry looking spots. That would be light burn...

 

[jiml74]

So sorry Droskee420. I did not mean to hijack your thread, it was just a great question. Lol, Aslo very bad math on my part.

 

[Egzoset]

I'm even worst on the calculations - hence the reason why i appreciate this thread myself!

75 lumens per square feet hey?!

Taking notes...

 

[Nelson]

My tank is 32 sq ft. 4'X 8'. I use 28, 45 watt bulbs, that put out 3,000 lumens each, total 84,000 lumens. That is about 2,600 lumens per sq. ft. I never feel that my tank is overlit. I don't have plant burn and the tank grows fine. Sure is a lot more light per sq. ft than you are talking about. I t sounds like not enough light to me.

Maybe you mean your box is 36 cubic feet? But square feet, it's 6. Length x width = square feet. And Length x Width x Height = Cubic Feet..:thumbs:

Anyway, you have plenty of light there dude. One more wound hurt a thing...

@jiml74
OOPS.. your not the original poster of the thread. Sorry. Thought I was talking to droskee420. You can have to much light, but yours sounds fine. Just watch for any white dry looking spots. That would be light burn...

 

[jiml74]

My box is 2 feet long 3 feet tall and 1.5 feet deep. so I think that makes my box 9 cubic feet.

I was just trying to figure out the optimal amount of light. I know is when I open the box its dam bright. Lol

 

[Stunted]

My box is 2 feet long 3 feet tall and 1.5 feet deep. so I think that makes my box 9 cubic feet.

I was just trying to figure out the optimal amount of light. I know is when I open the box its dam bright. Lol

I use the following as a rough guide:
HID lights around 50 - 75 w per sqf
CFL lights around 75 - 100+w per sqf

So I would be aiming for around 300w with CFL's or a 250 MH/HPS in that space (2 x 1.5 = 3)