CFL: Calculations and Room Design

Since I'm in <3 with Compact Fluorescent Lighting (CFL) I wanted to spend some time today to share with you what I've found during my hours of research.

Not only are these the best way to light (cost, efficiency, growth) vegetation for the least amount of money spent in intial costs and expenses of operating the lights they are flexible enough to be used in extremely small spaces. They produce very low amounts of heat allowing them to be placed directly next to the vegetation.

After all, 'compact' is in the name!

Since we are recreating the outside invironment inside we must work with at least 10,000 Lumens per square foot as the sun produces that much light, on average, on Earth during a sunny summer day.

Here is an equation every inside grower should have burnt into their brains:

The Inverse Square Law

E = I / r*r

E = Illuminance
I = Pointance
r = Distance

Illuminance is the amount of light emitted over an area, whether you are using Metric or Standard measurement, produced by the Pointance (source of light) at a specified Distance.

For example, 1 unit of distance from the Pointance to the perpendicular object would calculate as such:

E = I / 1*1

If we assume the Pointance is producing 10,000 Lumens (L):

E= 10,000L / 1*1

E = 10,000L per square unit area

If the Pointance is situated at 2 units of distance above the perpendicular object, assuming the pointance is producing 10,000L:

E = 10,000L / 2*2

E = 2,500L per square unit of area

That is one fourth (1/4) of the light per 1 square unit of area. This means, if the pointance is twice the distance it will require four times the light to cover the area with 10,000L.

E = 40,000L / 2*2

E = 10,000L per square unit area.

Given this knowledge of how light spreads over an area, not diminishes, the CFL's have an obvious advantage over high-intensity discharge (HID) lamps. HID lamps produce so much heat that they require distance from the canopy of vegetation to prevent burning and potential destruction of the vegetation.

For example, a high-pressure sodium (HPS) lamp producing 95,000L per 600 watts (w) of energy consumed (158.3L/w) situated 4 units of distance above the canopy would look like this:

E = 95,000L / 4*4

E = 5,937.5L per square unit area

Same equation with a 1000w HPS producing 140,000L (140L/w):

E = 140,000L / 4*4

E = 8,750L per square unit area

Notice how the 600w HPS is more efficient in terms of L/w than the 1000w a the same distance. The 600w HPS is producing 158.3L/w and the 1000w HPS produces 140L/w.

With proper ventilation, or even water-cooling, the HPS can be set closer to the canopy (within 2 ft.). This is of course costs quite a bit of money while the CFL's can be set right next to the canopy with no extra equipment and a very low initial cost.

One 600w lamp can be had for $100.00, then there is the hood/reflector, socket/cord, ballast, and ventilation/water-cooling. This could easily add up to $1,000. The 1000w counter-part is around the same price.

Now, lets compare some CFL's to each other and then back to the HPS lamps. Keep in mind that CFL's are *self-ballasted* (the ballast regulates the electricity to maintain a steady current).

These do not require anything special, household socket and wiring will work:

13w; 700L = 53.8L/w
15w; 900L = 60L/w
26w; 1,700L = 65.3L/w
30w; 2,000 = 66.7L/w
32w; 2,100L = 65.6L/w
40w; 2,800L = 70L/w
55w; 3,600L = 65.5L/w

These require special sockets, but standard household cords:

125w; 8,000L = 64L/w
150w; 10,000L = 66.7L/w
200w; 12,000L = 60L/w
250w; 15,000L = 60L/w

One more factor to consider is the HID's wear out quickly. Through half of their life the light emitted could drop as much as 50% and they will still look bright as hell. The CFL's generally just go out. I've sure the quality degrades a bit, but since they aren't as hot as the HID's they will maintain light out-put better longer.

All of the CFL's listed can be had for under $100 and only the big ones need the special socket and standard household cord. With heat still being emitted from these CFL's you'll only need a simple fan (you should already have these for circulation) to cool the growing space.

Since the CFL's can be placed right on the canopy you can pretty much throw out the Inverse Sqaure Law. Not only that, but they come in the blue and red lighting spectrum for all stages of growth.. for the SAME price.

Now that we've compared the CFL's to themselves lets find the most efficient CFL's (L/w) and compare them to the HPS lamps.

CFL:
40w; 2,800L = 70L/w
150w; 10,000L = 66.7L/w

HPS:
600w; 95,000L = 158.3L/w
1000w; 140,000 = 140L/w

In order for a CFL to match the initial lumen output of the HPS it would take:

34 - 40w CFL's
9.5 - 150w CFL's

Now, let's apply that nifty little equation from the beggining of this thread:

The Inverse Square Law

E = I / r*r


E = 95,000 / 4*4

E = 5,937.5L per square unit area

E = 140,000 / 4*4

E = 8,750L per square unit area


Since the CFL's produce very little heat compared the HPS lamps they will be placed right next to the canopy practically negating the Inverse Square Law in this setup.

Now, let's see how many lumens can be spread over a 4x4 area with CFL's:

34 - 40w CFL's = 95,200L
10 - 150w CFL's = 100,000L

Now, let's divide that total Lumen output by 16 (4x4) to see what we get over a 1x1 area:

34 - 40w CFL's = 5,950L per square unit area
10 - 150w CFL's = 6,250L per square unit area

Keep in mind we are trying to get at least 10,000L per square unit area, that would still take two 600w HPS.

Since the CFL's are compact they can be used in much smaller, more efficient designs.

Let's say we can fit this into a 2x2:

34 - 40w CFL's = 95,200L
10 - 150w CFL's = 100,000L

34 - 40w CFL's = 23,800L per square unit area
10 - 150w CFL's = 25,000L per square unit area

Given different designs, light placement, soil or hydro, ScroG, SoG, supplimental lighting, nutrition, and grower experience will ALL affect the end yield.

As you can see from the math the CFL's have a very good chance of being equivalent to the HPS.. and even surpassing them with Lumens given an area.

Another huge factor is the Color Rendering Index (CRI). Most HPS lights only provide up to 80% CRI. While CFL's claim 100% CRI. CRI is how well the lamp can recreate natural sun light.

Remember, anyone can get these CFL's at almost any store these days. They use normal sockets, except for the big ones, and normal household plugs. The price is noticably cheaper and easier to maintain.

Just something to think about with your current setup or a noOb starting out in their closet.



Enigma

Huh!
HuH! what

Wow... nice work, very helpful in aiding my decision def. going for cfl now =D

Peace

This is what makes CFLs ideal for small grows (2 - 5 plants). However for larger grows, I would definitely go with HID. It should also be said that the setup can be a bit of a pain w/ CFLs too. You have to move the lights often; sometimes daily, sometimes twice a day if you keep them really close when you first start flowering.

I turn my plants a quarter turn every other day, and that means moving lights to get them close but not too close. It can be back breaking in a tight space. It should also be said that heat can get to be a problem w/ large numbers of CFLs in tight spaces. That said they can produce some really nice results as evidenced by several journals on this site.

I'm loving CFLs right now and HID is not an option for me at this time. Check it out if you considering CFLs https://www.rollitup.org/cfl-growing/50550-poppinsmokey-s-first-grow-cfl.html

poppinsmokey said:

This is what makes CFLs ideal for small grows (2 - 5 plants). However for larger grows, I would definitely go with HID. It should also be said that the setup can be a bit of a pain w/ CFLs too. You have to move the lights often; sometimes daily, sometimes twice a day if you keep them really close when you first start flowering.

I turn my plants a quarter turn every other day, and that means moving lights to get them close but not too close. It can be back breaking in a tight space. It should also be said that heat can get to be a problem w/ large numbers of CFLs in tight spaces. That said they can produce some really nice results as evidenced by several journals on this site.

I'm loving CFLs right now and HID is not an option for me at this time. Check it out if you considering CFLs https://www.rollitup.org/cfl-growing/50550-poppinsmokey-s-first-grow-cfl.html

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Exactly!

The number of lights to even come close to a HID system is daunting. For larger grows the simplicity of the HID setup is a big factor. If you want one good plant, or maybe 4 good plants, a small room surrounded with CFL's will be VERY efficient. For a tight space (low volume) ventilation is a MUST! Those plants like to breathe!

For a space 2x2:

4 150w CFL's will produce 10,000L per square ft.
14 40w CFL's will produce 9,800L per sq. ft.

So, for a closet op this might be well considered. Combine this with a very simple Deep Water Culture (DWC) hydro setup you could produce some very nice plants!



Enigma

How do you understand the described watt numbers(cfl)? It's a used up power or delivered power(in watt numbers)?
Sorry for my bad english........
Peace

SunZa said:

How do you understand the described watt numbers(cfl)? It's a used up power or delivered power(in watt numbers)?
Sorry for my bad english........
Peace

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The watts are how much energy the bulb needs in order to light. The amount of lumens is how much light is emitted from the lamp.

If you take the total lumens and divide that by the amount of watts consumed you will see how much light per watt is generated by the bulb. The lower the number the less efficient it is, the higher the number the more efficient it is.

This is critical in selected your lights.



Enigma

Enigma, thanks for all the sciencey stuff.

Sorta.

Luminous intensity, measured in lumens, is a measure of the energy or push behind your photons, aka brightness, as the eye perceives it. It's an analogue of voltage in an electrical circuit.

Placing 2 CFLs next to one another does not make them any brighter or more intense. Therefore, lumens don't 'add' when 2 CFLs are used to cover the same area.

If both of your CFLs are 1500lm, the intensity in lumens in the area covered by 2 CFLS is... wait for it... 1500lm. You are throwing more low energy photons at your lighted area from more angles (from 2 sources), not photons with greater energy, 'push' or brightness. It's the energy of the photon striking the leaves that drives photosynthesis and allows light to penetrate foliage. Intensity is what cannabis needs to grow heavy, dense buds.

You could put 110 x 1500lm CFLs over a 20sq ft area, but for the above reason, you'll never ever get the yield and density of the 165,000 lm from a single 1000HPS. You could put a million of them in the same room and not one will get any brighter.

Moreover, HPS is much more efficient than CFL in watts per lumen. 110 14W (1500lm) CFLs would consume about 1540W.

HPS delivers high intensity light, well suited for cannabis, necessary for dense flower formation. The low intensity light from CFLs will yield sparse growth, long internodal distances and fluffy buds- and much lower yields per watt than HPS.

Your price estimate of over $1000 for a cooltubed 600W HPS is just plain nuts. Go shopping and find out what they really cost.

I can buy a 600 ballast for about $85, cooltube with built-in socket & reflector for $85, 600HPS lamp tube for $39, 150mm blower for $57, 6m of ducting for under $15. All up for an air cooled 600, $281.00.

Now go out and get an HPS and grow some dope.

Al B. Fuct said:

Enigma, thanks for all the sciencey stuff.

Sorta.

Luminous intensity, measured in lumens, is a measure of the energy or push behind your photons, aka brightness, as the eye perceives it. It's an analogue of voltage in an electrical circuit.

Placing 2 CFLs next to one another does not make them any brighter or more intense. Therefore, lumens don't 'add' when 2 CFLs are used to cover the same area.

If both of your CFLs are 1500lm, the intensity in lumens in the area covered by 2 CFLS is... wait for it... 1500lm. You are throwing more low energy photons at your lighted area from more angles (from 2 sources), not photons with greater energy, 'push' or brightness. It's the energy of the photon striking the leaves that drives photosynthesis and allows light to penetrate foliage. Intensity is what cannabis needs to grow heavy, dense buds.

You could put 110 x 1500lm CFLs over a 20sq ft area, but for the above reason, you'll never ever get the yield and density of the 165,000 lm from a single 1000HPS. You could put a million of them in the same room and not one will get any brighter.

Moreover, HPS is much more efficient than CFL in watts per lumen. 110 14W (1500lm) CFLs would consume about 1540W.

HPS delivers high intensity light, well suited for cannabis, necessary for dense flower formation. The low intensity light from CFLs will yield sparse growth, long internodal distances and fluffy buds- and much lower yields per watt than HPS.

Your price estimate of over $1000 for a cooltubed 600W HPS is just plain nuts. Go shopping and find out what they really cost.

I can buy a 600 ballast for about $85, cooltube with built-in socket & reflector for $85, 600HPS lamp tube for $39, 150mm blower for $57, 6m of ducting for under $15. All up for an air cooled 600, $281.00.

Now go out and get an HPS and grow some dope.

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The point I was trying to make was: at this point for anything small a CFL could produce enough light to veg and flower a plant. Going any bigger than say a 3' x 3' area the amount of CFL's needed to cover that area would be tremendous compared to an HPS.

Next, CFL's are still pretty much infants technology-wise.. maybe they will get better in the future. At this point the HPS blows them away comparing the amount of light per bulb. Any grow mag will show you the comparison between the HPS and the other bulbs.. and how many it would take to match its power.

The HPS does penetrate the vegetation better than the CFL's. There is no question about that. The offset to that is the CFL's can be placed within inches all around the grow for better coverage. Lower intesity = more lights, higher intesity = less lights.

Using any fluorescent has produced small, bushy plants with closely stacked nodes. The 1000w MH from the last DWC grew tall skinny stalks which needed support for the entire life of the plant. The HPS only made this worse. I switched to fluorescents and since birth they've stayed tight and bushy.

The places I've priced the HPS setup have been pretty high.. I'd like to know where you could get one so cheap.. I've got a new setup in mind like I showed you.

For my purposes, I'm looking for a 400 MH and 600w HPS vented hood.. if I could find a cool-tube that could handle both with a "bat-wing" reflector for that price I'd be going NUTZ!

Anything from the local shop is obviously going to be raping my wallet..



Enigma

Enigma said:

The point I was trying to make was: at this point for anything small a CFL could produce enough light to veg and flower a plant.

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Whether flowering 1 or 100, CFLs will always produce poor results compared to HPS. They are simply not suitable for flowering due to their low-intensity output.

However, by no means are fluoros useless. CFLs or plain tube fluoros are great for seedlings and clones- and in fact are the preferred tool for that job. They're just the wrong tool for flowering.

Next, CFL's are still pretty much infants technology-wise.. maybe they will get better in the future.

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CFLs are not a young technology at all. They are simply fluorescent tubes bent or coiled to conveniently fit sockets intended for typical incandescent lighting. Would you believe fluorescent (low pressure mercury arc) lighting has been with us since 1901?

CFLs, with their internal electronic ballasts, are indeed something of an improvement on regular fluoros with coil and core (magnetic) ballasts, but ballasts are simply current limiters. The electronic means of current limiting is still just current limiting, accomplished in CFLs with more compact and lightweight circuitry.

CFLs and traditional cylindrical tube fluoros have similar luminous output per watt. CFLs are about 10% more efficient than a fluoro with a coil & core ballast, owing to the lack of eddy current losses as happens in an iron cored inductor.

The main benefit in CFLs isn't greater output nor significantly improved efficiency, though... It's the ability sell a hell of a lot more of them because they can fill all those billions of existing incandescent light sockets out there!

The cheap, disposable electronic ballast circuitry in CFLs has been made possible by recent developments in surface-mount electronic component technology and high-speed automated circuit board production. It has been possible for a very long time to make electronic ballasts for fluoro lighting; making them so cheaply you can afford to throw away the ballast when the tube wears out is the only thing that's new.

Your love affair with CFLs has come about because they are inexpensive and very easy to use- and are available for sale damn near everywhere, including in any supermarket. Don't fool yourself into believing that CFLs are any sort of an improvement over typical cylindrical fluoros- they're just easier to use, cheaper to buy and easier to find than cylindrical tube types.

The HPS does penetrate the vegetation better than the CFL's. There is no question about that. The offset to that is the CFL's can be placed within inches all around the grow for better coverage. Lower intesity = more lights, higher intesity = less lights.

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Fluoros will never deliver the luminous intensity of HPS, even accounting for spacing required by HPS. Cooltubes on HPS lights allow even closer spacing to leaves. I don't think you've grasped the order of magnitude difference in the intensity of HPS v fluoros. Even though intensity reduces with distance by an inverse square rule, HPS has enough intensity to make up the difference- and then some.

Using any fluorescent has produced small, bushy plants with closely stacked nodes. The 1000w MH from the last DWC grew tall skinny stalks which needed support for the entire life of the plant. The HPS only made this worse. I switched to fluorescents and since birth they've stayed tight and bushy.

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If you got spindly plants from a 1000MH or 600HPS, you had other problems and the first place I'd look for trouble is your thermometer. Excessive air temp is another good way to induce stretchy plants, aside from insufficient light. If your op consistently exceeded 26-27C, you just found the cause of the stretch. Excessive heat isn't a failure of the HID lighting- it is a failure to set up the op to remove the heat these lights produce.

Fault #1 in 90% of the grow ops I look at is failure to install sufficient ventilation to suit the plants and shift the heat from lights. When choosing a space to grow in, the ability to ventilate the space must be the very first consideration but is usually the very last, creating loads of problems down the track.

The places I've priced the HPS setup have been pretty high.. I'd like to know where you could get one so cheap.. I've got a new setup in mind like I showed you.

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I haven't seen your new setup. Got a link?

My information on suppliers won't be worth much to you unless you're in Australia, but diligent shopping should turn up broadly similar prices.

For my purposes, I'm looking for a 400 MH and 600w HPS vented hood.. if I could find a cool-tube that could handle both with a "bat-wing" reflector for that price I'd be going NUTZ!

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Remembering for the moment that lumens don't 'add' and recalling your mention in post #1 in this thread that light intensity reduces by a function of an inverse square rule, using two HID lights isn't of great benefit. Using two of differing output will pose mounting complications. The 400 will need to be closer to the plants than the 600 to get best use of its luminous output, so you won't want it in the same fixture as the 600. If you are trying to cover the same area with both of those lights, the 400 being closer than the 600 will mean that it's actually in the way of light coming from the 600.

You will find some old-style enclosed hood fixtures out there which can handle 2 HID lamps at once, but again, since lumens don't 'add,' they are of dubious benefit even if equipped with a pair of matching HID lamp tubes.

Those sellers which spruik the benefit of using MH & HPS together for flowering are downright ponderous. WHY would you do it? It is the red-orange spectrum of HPS which best mimics late autumn sunlight, when coupled with a 12/12 light cycle, both which trigger cannabis' DNA to make flowers.

Anything from the local shop is obviously going to be raping my wallet..

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Shop online or simply at other hydro shops. You can't possibly have access to only one hydro shop.

If I had your gear, I would be raising mums with the 400MH and flowering with the 600HPS in a cooltubed batwing.

Heh I remember when my post was the only one remotely addressing these issues. Im so proud ^^

Listening to these two obviously very intelligent guys debate this topic makes me feel like a Ten year old, holding an Ice cream.....smarter than I'll ever be.....Must be the 2000 hits of Ecstacy I took...

Damb Al, looks like you ventured off your thread for this one! Good to read a post from you.....I mean out side of your thread that is! C

K thx for all that, but let me stop y'all for just a minute. I'm not writing what I have written either to debate nor win any debates. It's just a straight comparison between the two sorts of lighting and how best to apply them given their inherent benefits and limitations.

dcg, I can't promise to venture far from the Get A Harvest Every 2 Weeks thread- I just don't normally have the time for it. I'm procrastinating some manicuring work at the moment, therefore... I have an excuse.

My right thumb is killing me at the moment! So I think we are in the same boat right now....

CFL's are great for my hallway....600w HPS in a air cooled hood powered by a quality electronic ballast, that runs so cool that I can let my plants grow into it, now that is for my op....

I hate to say it, but I don't have a lot of love for electronic ballasts for HPS just yet. They don't have the nearly decades-long reasonable service life of well made coil & core ballasts and the heat issue is solved by putting the ballast outside the grow room airmass.

I did a side-by-side comparison of a Lumatek 600 ballast and a typical magnetic and found identical luminous intensity from a single HPS used in testing- despite some sales claims of up to 30% greater intensity with the Lumatek. The Lumatek drew about 55W less than the magnetic, about a 9% power savings. The Lumatek did live up to sales claims about low heat emission, running cool as a cuke, while you could keep your coffee warm on the magnetic (don't try this at home, kids ).

If you must locate your ballast in the op airmass, a Lumatek is for you. If you really need to save 9%, well, same deal.

However, semiconductor devices in power electronics applications are simply more prone to failure in long service usage than the much simpler iron cored inductor based ballasts. At the end of the day, it's a lot easier to break a transistor junction than it is to break a coil of copper wire.

Sometimes simpler is better, but there's a trade-off.

Since the topic on this thread is about room design, I hope I am not stepping on your toes Enigma with these post about Lights....I love the old school mentality Al, I am of a younger Millennium generation that will always try to do as little for the most gains....That is when efficiencies of the Electronic ballast come into play..I hope to use less energy, thus lowering my power bill "less overhead" ie:work. I think we are onto a new era for ballasts, as long as they hold up over time...Which mine are doing very well...Hell, just the shipping charges are lower due to there lighter weight, and smaller size. So on and so forth...

Al B. Fuct said:

I hate to say it, but I don't have a lot of love for electronic ballasts for HPS just yet. They don't have the nearly decades-long reasonable service life of well made coil & core ballasts and the heat issue is solved by putting the ballast outside the grow room airmass.

I did a side-by-side comparison of a Lumatek 600 ballast and a typical magnetic and found identical luminous intensity from a single HPS used in testing- despite some sales claims of up to 30% greater intensity with the Lumatek. The Lumatek drew about 55W less than the magnetic, about a 9% power savings. The Lumatek did live up to sales claims about low heat emission, running cool as a cuke, while you could keep your coffee warm on the magnetic (don't try this at home, kids ).

If you must locate your ballast in the op airmass, a Lumatek is for you. If you really need to save 9%, well, same deal.

However, semiconductor devices in power electronics applications are simply more prone to failure in long service usage than the much simpler iron cored inductor based ballasts. At the end of the day, it's a lot easier to break a transistor junction than it is to break a coil of copper wire.

Sometimes simpler is better, but there's a trade-off.

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That is the exact issue I'm having at the moment.

Using T5's for veg I've seen a noticable increase in 'bush'. At the same temp and humidity we had horrible problems with stretchy plants using a HID. The only thing I can chalk it up to is the fluoro's.

Now, for the 4x4 space I'm using a simple 1000w HPS will suit nicely. I don't have the time or patience for such a big space to stack CFL's. The CFL's are great for veg, or flower on a small scale.. say a closet grow.. which are most of the questions asked on here.

I agree, CFL's can't match the intensity of the HPS. For a small space they, in my mind, would be prefered over the HID anyday. The yield wouldn't be as good as a HID, but if the HID fried them.. there would be NO yield.

See what I'm getting at?

HPS = great if space is available
CFL = great if space is confined

Maybe in the future the CFL's will become more powerful.. for now I'm just relying on math to dictate my decision.

Now, the real question is how long will those electronic ballasts last?

I'm not sure if the ballast will be able to be situated outside of the enclosed area.. so this might be an option.

The other issue is, if it will burn the bulb if it fails or if the ballast itself will just fail.

daddychrisg said:

Now, the real question is how long will those electronic ballasts last?

The five year warranty is good enough for me!

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That is something I can rely on.. but if it goes out I will be fucked waiting for a new one.