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6500K 3K Lumen Fluorescent vs 6500K 2.3K Lumen LED. Which is the better choice?


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Old 10-26-2016, 06:34 AM
Psycrops Psycrops is offline
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Default 6500K 3K Lumen Fluorescent vs 6500K 2.3K Lumen LED. Which is the better choice?

I plan on growing lettuce/kale hydroponically.
-----
Was curious what you all think might be sufficient for my purpose.
I'm also looking at it from a long-term price perspective as well.

It basically comes down to these options:

fluorescent: 6500k - 3050lumens - 86CRI - 32w - $1.59 per bulb

vs

led: 6500k - 2300lumens - 80CRI - 22w - $10.16 per bulb
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Will be using 3 hydroponic raft setups (all a mixture of lettuce/kale).
This comes to 3 fixtures per raft (2 bulbs per fixture).
3 fixtures x 2 bulbs = 6 bulbs per RAFT x 3 RAFTs = 18 bulbs total.
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Pricing Long-Term

~Fluorescent
Upfront Costs: $39.75 for 25 bulbs (I only need 18, but it's required that I buy a case (those can be backups I guess))
Monthly Energy Costs = $34.21
Yearly Energy Costs = $410.57

$450.32 = first year costs total for energy and bulbs.

~LED
Upfront Costs: $182.88 for 18 bulbs
Monthly Energy Costs = $23.52
Yearly Energy Costs = $282.24

$465.12 = first year costs total for energy and bulbs.

$15 more than the fluorescent, but more efficient/last longer, and end up saving $128.33 in energy costs the next year + years after that.

So the LEDs pay for themselves in the first year and save much more in the upcoming months/years.
-----
QUESTION: What would you all choose?

Is the lose in lumens really all that bad considering what I'm growing?

I tried researching the importance of lumens and only came up w/ a sq ft lumen number that didn't seem to have much confidence behind it.

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Old 10-27-2016, 01:03 AM
trurl trurl is offline
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I have really no idea what I am talking about, but I did just get through setting up homemade leds for my first grow! If you are getting just led bulbs you will need a lot more than just the bulbs themselves. Are you getting panels?
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Old 10-27-2016, 02:15 AM
GpsFrontier GpsFrontier is offline
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Hello Psycrops,
I would use florescent lights for growing lettuce and kale on small scale. HID (metal halide) lights on large scale. Why? Because it's the most cost effective, and being cost effective is very important to me. You said you plan to have 3 raft systems but you didn't say how many Sq feet it would be. First I wouldn't grow lettuce and kale in the same system since kale needs a stronger nutrient solution than lettuce.

Manufactures of LED lights like to promote their products as more energy efficient. But in reality you don't save much at all, and if you do manage to save some money in electricity, it will take between 5 and 10 years to break even for the much higher equipment costs. I'm not going to wait that long to start saving.

Two 4 foot twin bulb T5 florescent lights (216 watts) is enough to cover a 2x4 foot space (8 Sq feet), possibly even a 3x4 foot space (12 Sq feet). Or 6 four foot T8 bulbs (192 watts) to cover the same space. Since you will need between 25 and 35 watts of LED lighting per SQ foot, you won't be saving anything. In fact it will probably cost more to run LED lights.

For this example I will use the smaller Sq footage of 8 Sq feet

Florescent
T5's-216 watts covers 8 Sq feet

LED
8 Sq feet x35= 280 watts (64 watts more than T5 Florescent).
8 Sq feet x25= 200 watts (16 watts less than T5 Florescent).

Even if you can manage to do OK with using just 25 watts per Sq foot of LED lights you would only be saving 16 watts. Using the national average of 10 cents per kilowatt hr, those 16 watts only save you $0.86 cents a month running the lights for 18 hours a day.

$0.86 x 12= $10.32 a year, and $51.60 after 5 years, and $103.20 after 10 years.

Now when you run the numbers you have to take into consideration the cost of the lighting fixtures as well, not just the bulbs. By the time you add up the equipment cost for both types of lighting, and divide that by the little energy savings if any, it can easily take 10 years just to break even.

Not only do LED not really save you much at all in electricity, but LED lights aren't all the same. Manufactures sell blue, red, and white LED's. But there is a vast difference in both actual light wavelengths emitted, as well as intensity and concentration of those wavelengths from one LED bulb to another even if they are the same visible color. In other words, you won't get the same results from every LED light even if they are the same color spectrum.

What Wavelength Goes With a Color?
Light Absorption for Photosynthesis
Light and photosynthetic pigments
Which regions of the electromagnetic spectrum do plants use to drive photosynthesis?
What are these Pigment involved in Photosythesis?

As for your question about the importance of lumens for plants. There are many ways of measuring light intensity, lumens is just one of them and isn't really important to plants. Comparing lumens is only useful in comparing one bulb to another bulb of the same type. What is important is the actual wavelength of that light. Light is wavelengths. Plants use certain wavelengths in different processes, and the measurement of lumens doesn't measure the specific wavelengths plants use. That would be PAR (Photosynthetically active radiation).

As I said lumins is only useful in comparing similar bulb types. As an example, if you were comparing Metal Halid Bulbs, and a 400 watt MH bulb put out 36,000 lumens, and the 200 watt bulb put out 18,000 lumens, and the 100 watt bulb put out 9,000 lumens, you can see that the lumen output is proportional to the wattage, and you can assume the par output will be proportional as well. In other words four 100 watt bulbs would give you the same lumen/par output as one 400 watt bulb. But since distance from the bulb is important, you could space the 4 lower wattage bulbs out and get better overall coverage from the 4 bulbs than the single higher wattage bulb, and for the same amount of electricity/wattage consumed.
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Old 10-27-2016, 07:22 AM
Psycrops Psycrops is offline
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Quote:
Originally Posted by trurl View Post
I have really no idea what I am talking about, but I did just get through setting up homemade leds for my first grow! If you are getting just led bulbs you will need a lot more than just the bulbs themselves. Are you getting panels?

These are LEDs that are used in a T8 fixture. You just rewire the ballast slightly and they work (or so it's said). No panels.



Quote:
Originally Posted by GpsFrontier View Post
Hello Psycrops,
I would use florescent lights for growing lettuce and kale on small scale. HID (metal halide) lights on large scale. Why? Because it's the most cost effective, and being cost effective is very important to me. You said you plan to have 3 raft systems but you didn't say how many Sq feet it would be. First I wouldn't grow lettuce and kale in the same system since kale needs a stronger nutrient solution than lettuce.

They grow area per raft will be 55"L x 45"W and around 20-25"T of wiggle room for the lights/plants, which works out to 16.25sq ft. Lettuce will occupy the top raft and kale for the other two rafts. Kale also grows taller so it will have more height in that area. I already got the PPM/EC/CF and preferred pH figured out for the different varieties.

The fixture is 48"L x 5.5"W. They will be spaced 7" apart w/ 7" of space @ the end.

If using 1,500 lumens per sq ft, it comes out to 18,300 lumens w/ fluorescents & 13,800 w/ LEDs (24,375 lumens needed). I guess that's how it's measured out.

The numbers don't make since. Seems many sources have different numbers and for the most part, seems like they're being pulled out of someones ass w/ no reasoning behind it. Ive seen grows use much less. If worse comes to worse, I can always use less grow space and tighten fixture gaping.

The interior top/bottom/sides/+raft base will also be wrapped in mylar which should hopefully help with maximizing light.


Quote:
Originally Posted by GpsFrontier View Post
Manufactures of LED lights like to promote their products as more energy efficient. But in reality you don't save much at all, and if you do manage to save some money in electricity, it will take between 5 and 10 years to break even for the much higher equipment costs. I'm not going to wait that long to start saving.

Two 4 foot twin bulb T5 florescent lights (216 watts) is enough to cover a 2x4 foot space (8 Sq feet), possibly even a 3x4 foot space (12 Sq feet). Or 6 four foot T8 bulbs (192 watts) to cover the same space. Since you will need between 25 and 35 watts of LED lighting per SQ foot, you won't be saving anything. In fact it will probably cost more to run LED lights.

The numbers I ran above show the LEDs to be on par with the fluorescents in terms of costs for the first year, and dropping to around 31% in energy costs the following years. That's not real word though numbers though, just something to go by. Not 100% sure how efficient the brand I'm getting is, as they're from overseas.

If using wattage per sq ft, LED-25w per sq ft would put it @ 406.25w required. The LEDs only total to 132w (22w/6 bulbs). Which means I would need 274w/12 more bulbs ($121.92) and around $90 more in light fixture money.




Quote:
Originally Posted by GpsFrontier View Post
Even if you can manage to do OK with using just 25 watts per Sq foot of LED lights you would only be saving 16 watts. Using the national average of 10 cents per kilowatt hr, those 16 watts only save you $0.86 cents a month running the lights for 18 hours a day.

The only thing that peaked my interest to the LEDs was being curious if I could get away with using less lumens for my particular situation. Since that particular LED could fit the fixture I was looking at, it was the cheapest of the LEDs and the fluorescent was the cheapest of the fluorescent.

If factoring lumens or wattage per sq foot, then LEDs will never win as you're always going to need to match wattage or lumens regardless of bulb type. The only thing it seems LED has over fluorescent is lumens per wattage and bulb life (quality control issues don't factor in), which my above options put it to around 104 lumen per watt for the LED and 95 lumen per watt for the fluorescent. So @ the end of the day that's not much cost savings to do cartwheels over.


Quote:
Originally Posted by GpsFrontier View Post
As I said lumins is only useful in comparing similar bulb types. As an example, if you were comparing Metal Halid Bulbs, and a 400 watt MH bulb put out 36,000 lumens, and the 200 watt bulb put out 18,000 lumens, and the 100 watt bulb put out 9,000 lumens, you can see that the lumen output is proportional to the wattage, and you can assume the par output will be proportional as well. In other words four 100 watt bulbs would give you the same lumen/par output as one 400 watt bulb. But since distance from the bulb is important, you could space the 4 lower wattage bulbs out and get better overall coverage from the 4 bulbs than the single higher wattage bulb, and for the same amount of electricity/wattage consumed.

For my particular setup size. I couldn't get away w/ using a MH in my setup as I only will have 20-25"T of room per raft. I should had mentioned this earlier, but the rafts stack on top of each other. The whole setup will be around 59"L x 48"W x 80-90"T and will house 3 rafts.

MH is the best bet, but I wish they made longer bulbs as I have some ground to cover. Plus they're only around $8 which is absolutely nuts.


Thanks for the informative feedback. Maybe I'm over complicating stuff.
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Old 10-28-2016, 01:06 AM
GpsFrontier GpsFrontier is offline
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Hello Psycrops,


Quote:
The interior top/bottom/sides/+raft base will also be wrapped in mylar which should hopefully help with maximizing light.
While Warping mylar around the plants will help reflect light, it will also cause air circulation problems. Air circulation is very important not only for plant health, eliminating heat build up, but also for providing CO2 the plants need to grow as well.

Quote:
The only thing that peaked my interest to the LEDs was being curious if I could get away with using less lumens for my particular situation. Since that particular LED could fit the fixture I was looking at, it was the cheapest of the LEDs and the fluorescent was the cheapest of the fluorescent.
First good LED grow lights aren't cheap. The price is coming down, but their still not cheap yet.

Quote:
Not 100% sure how efficient the brand I'm getting is, as they're from overseas.
Price doesn't guarantee good quality either since many Chinese companies charge high prices for low quality LED's. So you really have to do your research on the company manufacturing the lights in the first place. Don't trust manufactures propaganda. It's time consuming to do so, but I have seen countless people who were so excited they were going to save so much money in electrical costs, only to find out later after they spent all their money that they weren't really going to save much of anything in reality, and/or the plants were growing malformed.

Quote:
If using wattage per sq ft, LED-25w per sq ft would put it @ 406.25w required. The LEDs only total to 132w (22w/6 bulbs). Which means I would need 274w/12 more bulbs ($121.92) and around $90 more in light fixture money.
When planing to use LED's you really have to do your own testing. Like I said LED's aren't all created equal, and good ones aren't cheap. With cheap quality LED grow lights ones flooding market, you have to really research the manufacture, and even then do your own testing. The 25 watt to 35 watt per Sq foot recommendation isn't an absolute because it's going to depend on the quality of the LED's themselves. When I say Quality, I mean how they were designed and manufacture. It doesn't mater how many watts a light is putting out if it's not putting out enough PAR light (wavelengths plants use).

Here is a video that tested florescent lights with common LED grow lights.
Low Watt LEDs vs T5 Grow Lights: Seed Starting / Lettuce Test

While looking up the video to post for you, I found this new one he has put out as well.
T5 Fluorescent vs Transcend LED Grow Lights -Hydroponic Lettuce Test

He had good results using those LED's, so I ran the numbers, here's how it breaks down.

T5 florescent
4 foot twin bulb florescent light fixture with bulbs $40
$40x2= $80
216 total watts

T5 LED's
4 foot twin bulb florescent light fixture with bulbs $40 (you don't need the bulbs because you will be using the LED tubes instead, but they come with the fixture)
$40x2= $80
LED T5 bulbs $70 each
$70x4= $280
120 total watts

That's a $280 equipment cost difference.

Electrical costs calculated using the national average of 10 cents per kilowatt hr

Florescent 216 watts running 18 hours a day
Daily $0.39
Monthly $11.70

T5 LED 120 watts running 18 hours a day
Daily $0.22
Monthly $6.60
That's a $5.10 difference in electrical cost per month

$280 divided by $5.10= 54.9. So it will take 54.9 months to break even in electrical costs from the higher equipment costs. 54 months is 4.5 years. It will take nearly 5 years just to break even before you can actually start saving any money.

Even if you are willing to wait 4.5 years before you start saving any money, I find it ironic that the company has a 5 year warranty which tells me that's probably about the lifespan of the bulbs themselves. So just when you are about to start saving money, you will probably have to buy new bulbs and wait another 4.5 years to break even again. If the bulbs wear out before the 5 years, they wont replace them with new bulbs, they will just prorate them and you wont get hardly any money back or towards new bulbs anyway.

Quote:
The only thing it seems LED has over fluorescent is lumens per wattage and bulb life (quality control issues don't factor in), which my above options put it to around 104 lumen per watt for the LED and 95 lumen per watt for the fluorescent.
Again you cant really compare lumens from one type of bulb to another type of bulb. Florescent lights and LED lights are two very different bulbs. You can compare lumens from one florescent bulb to another florescent bulb, or compare lumens from one HID bulb to another HID bulb. But not a florescent bulb to a HID bulb or to a LED light. I don't think you can really compare lumens from one LED light to another LED light since LED's are so vastly different.

Quote:
For my particular setup size. I couldn't get away w/ using a MH in my setup as I only will have 20-25"T of room per raft. I should had mentioned this earlier, but the rafts stack on top of each other. The whole setup will be around 59"L x 48"W x 80-90"T and will house 3 rafts.

MH is the best bet, but I wish they made longer bulbs as I have some ground to cover. Plus they're only around $8 which is absolutely nuts.
I'm not sure if your planning to grow them on a shelving system, or side by side with the lettuce raised higher to be the same height as the kale. If your growing them on a shelving system I would go with using florescent lighting. But you don't need long MH bulbs/tubes to be able to use HID lighting. That's why I gave you the example of comparing lower wattage MH lights. You can get the same effect as using long tubes when you use lower wattage MH bulbs spaced out, and without using any more electricity. A typical 400 watt HID light will normally be able to cover a 8-10 foot wide space (80-100 Sq feet) depending on the plants and shading. I attached a drawing showing what I mean. If I read your figures correctly you plan to have 3 systems each just under 20 Sq feet, for a total of about 60-70 Sq feet give or take depending on how far apart each system is spaced, which should easily fit within the sq footage of the example in the drawing I made. 100 watt HID lights aren't easy to find, you really have to look around and make some calls to find them. But they do make them and here is a link to one I found. Mini Sunburst MH w/Lamp, 100W

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