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CFL Lumens/Watt Chart - Find Most Efficient Setup

Discussion in 'Indoor Growing' started by FirstTimeGrow, Apr 28, 2007.


    FirstTimeGrow Well-Known Member

    I am preparing to make a large grow area and want to use CFLs. I was wondering what the most cost effective setup would be and thought others might be interested in the Lumens/Watt ratios for CFLs.

    CFL Lumens/Watt

    105w - 65.714
    85w - 58.823 (49.412)
    65w - 52.308
    55w - 65.454
    42w - 66.667
    40w - 66.25
    32w - 65.625
    30w - 66.667
    27w - 64.815

    Based on my calculations it seems that the 30w-55w are the most efficient CFLs.

    dew-b Well-Known Member

    i have a 150w cfl that puts out 7900 lumes
    here is a link to it 150W 6500K Mogul Base Compact Fluorescent Grow Lamp - Plantlighting Hydroponics. it works real good i have had good resultz with it . my plants are doing real good. justgrowing 2 rightnow till i can build a proper grow box. have them in my pantery fornow. if ihad a camera iwould post some pics

    FirstTimeGrow Well-Known Member

    Thanks for posting about that

    7900/150 = 52.667

    Say you had 5 of these 30 watt bulbs:

    30 Watt - Full Spectrum High Definition - Compact Fluorescent - 30W/SPRING/64K - As Low as $3.98 ea.

    That would still be 150 watts, but these put out 2000 lumens each, so that would be 10,000 lumens for 150w instead of 7900 for 150w.

    Thanks for your post though, I'm trying to figure out what the most cost effective setup would be.


    cali-high Well-Known Member

    yeah go to home depot and get 3 42w bulbs

    nongreenthumb Well-Known Member

    don't go getting yourself confused,

    having 10 bulbs that put out 2000 lumens doesnt mean you get 20,000 lumens, it means you get 2000 lumens at a foot away with better light penetration covering a larger area.

    the 30 watt bulbs may well be the most efficient per watt

    light deminishes exponentially

    intensity = light output devided by square distance

    at 1 foot away those bulbs will put out the stated lumens change that to 2 foot away your going to get 500 lumens. 2000 lumens divided by 2 squared.

    so to get the most out of those bulbs you are going to have to have them really close to make sure you get enough lumens to the plant and have more per plant to make sure you get enough light penetration

    2000 lumens isnt going to be enough for the plant,
    and you will begin to see stretching when the plant is crying out for light.

    so yes per watt a single 30w bulb is more efficient than a 100 w bulb, but the 100w bulb is going to be better to grow with as it will give you sufficient lumens to get you to flowering.
    tokes' likes this.

    DoobsDay Well-Known Member

    those spiral cfls are exceptionally bad when it comes to light penetration and intensity, since these lights are designed to disperse light evenly in all directions, even with a good reflector not much is accomplished. id recommend buying the cfl floodlights, these cfls will put more light out in one primary direction.

    fdd2blk Well-Known Member

    those bulbs are good for what they say at no more than 2" away. once you pass 2" they aren't much at all.

    believe me.

    Attached Files:


    cali-high Well-Known Member

    very nice i was gonna buy one but do you really need one?

    nongreenthumb Well-Known Member

    or get a mh and hps and have fantastic plants

    either that or get a hps for flowering and a 6400k cfl 100 watt at least for veg

    DoobsDay Well-Known Member

    what did you expect there flourescents.

    buy a hps light or go outdoors

    nongreenthumb Well-Known Member

    have a look at fddsblk's pictures and posts and threads, I'm sure you will be embarrased by that remark

    DoobsDay Well-Known Member

    excuse me? more forum drama for you non green? fdd i meant no offense i was agreeing with you, i hope you saw that

    nongreenthumb Well-Known Member

    just seemed like you were telling one of the most experienced growers on here who grows both inside and out, has made his own strains to go buy a hps.

    Thats all, no drama

    midgradeindasouth Well-Known Member

    I got a trio meter ph/lumen/wetness for 9.50 at my local hydo store.
    I agree the light with cfl's diminishes rapidly at distances further than 2".
    The cfl's work good if you can maintain light distance from plant.
    From 3rd week of veg- 1st week of flowering I moved my cfl's daily.

    DoobsDay Well-Known Member

    my apoligies for not being clear, that comment was directed towards the one who started the thread

    nongreenthumb Well-Known Member

    well you did quote the fdd with that message, so thats probably where the misunderstanding came from

    I dont know if its just me or not, but is everyone expecting me to be kicking off every second now, just because i stood up for someone.
    ThE sAtIvA hIgH

    ThE sAtIvA hIgH Well-Known Member

    light diminishes the same wether its a cfl ,hps ,regular bulb etc etc

    nongreenthumb Well-Known Member

    The sativa high.

    If the option to give neg rep was still available, I would be most definately giving you loads right now.

    That avatar is disgusting, get something in blue !!!

    DoobsDay Well-Known Member

    nongreen maybe your reading into something that isnt there.

    "light diminishes the same wether its a cfl ,hps ,regular bulb etc etc"

    correct me if im wrong but are you saying cfls have the same reach HID as lights?

    nongreenthumb Well-Known Member

    that was the way it looked first off,

    it wasnt your intention and this bit of banter has gone further than it should have done, it was a misunderstanding that has been cleared up, i was just explaining how i misunderstood you.

    cfls dont have the same reach as hps

    the light deminishes just as quickly though

    intensity = lumens divided by distance squared

    that is the law of deminishing light

    so if you got a 2000 lumen cfl at a foot away

    2000 / 1 x 1 =2000

    2 foot away 2000 / 2 x 2 = 500

    600w hps

    92000 / 2 x 2 = 23,000

    so as you can see the light deminishes at the same rate but because the hps has more lumens to start with it has a further reach

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