Its a 10x10 room. What size exhaust fan and filter do I need. I was thinking of going big around 1100cfm with a 5 or 6 foot carbon filter. I also will have to filter the incoming air because I will be in a dank basement and need to keep all the mold and bacteria out. I also figured I would cool my 3 1000k lights with this clean air using a Y adapter or whatever its called. What size intake fan do I need. It will be pulling air in through a filter and one duct for fresh air and the rest will be split to the lights and out of the room (I dont know if that lessens the total cfms or not. I want to keep negative pressure but I dont want to burn a fan up. If this was your room what would you do. I am thinking a 500 in and a 1000 out roughly. will 500 be enough to cool my lights and fill the room with air.
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Fan question - intake and out
- Thread starter worg
- Start date
S
slave4sail
10x10x(assuming 10)=100 remember cubic kind of means 3d or 3 measurements needed. ! this calculation should actually be 1000! Hasty error in calculations, my mistake.
Without mention of any co2, I will assume you are just running open ends on the ducting? If so, you will want around 300cfm to maintain adequate exchange of fresh air for the space. That will translate to just about well made 6" inline fan. Bigger fan is always an option, and a something I will always suggest as long as adequate intake can be provided.
Getting to the intake, you do not need a separate fan for intake. One single fan creates both intake and exhaust, that is the design feature at it's purest form. The fan will create the negative pressure, and want to be fed adequate intake. These intakes are passive and require no additional force, other than the pressure created by the fan. An inline fan will have two openings, and usually an arrow depicting flow. One side is the intake, one the exhaust. If the grow space does not account for the required intake, then for sake of efficiency should be provided. It does not nescesarily have to be sourced by an additional fan, although that is perfectly fine should the design call for it. Utilizing an additional fan for intake helps when adequate passive intake area can not be provided. Either way, proper caluculations should still be made.
The intake should be though about in terms of area, rather than another fan size. If the area needed for passive intake is not available, by all means use an additional fan; but the math works all the same. The cubic area of the space and size of fan will dictate the amount of intake, and everything in the design should be matched for this.
500 in and 1000 out? There is 500 missing somewhere in there.
Assuming adequate intake provided:
A well made 6" inline fan can adequately pull this off with average to moderate ambient temperatures.
A well made 8" inline fan can pull it off with slightly higher ambient temperatures, and so on.
The total cfm will be unique to each individual product and should have available to you a flow chart at various pressure differences. Those figures are the most important to determining the outcome of your desired design application. Really hope this helps you and your room design.
Without mention of any co2, I will assume you are just running open ends on the ducting? If so, you will want around 300cfm to maintain adequate exchange of fresh air for the space. That will translate to just about well made 6" inline fan. Bigger fan is always an option, and a something I will always suggest as long as adequate intake can be provided.
Getting to the intake, you do not need a separate fan for intake. One single fan creates both intake and exhaust, that is the design feature at it's purest form. The fan will create the negative pressure, and want to be fed adequate intake. These intakes are passive and require no additional force, other than the pressure created by the fan. An inline fan will have two openings, and usually an arrow depicting flow. One side is the intake, one the exhaust. If the grow space does not account for the required intake, then for sake of efficiency should be provided. It does not nescesarily have to be sourced by an additional fan, although that is perfectly fine should the design call for it. Utilizing an additional fan for intake helps when adequate passive intake area can not be provided. Either way, proper caluculations should still be made.
The intake should be though about in terms of area, rather than another fan size. If the area needed for passive intake is not available, by all means use an additional fan; but the math works all the same. The cubic area of the space and size of fan will dictate the amount of intake, and everything in the design should be matched for this.
500 in and 1000 out? There is 500 missing somewhere in there.
Assuming adequate intake provided:
A well made 6" inline fan can adequately pull this off with average to moderate ambient temperatures.
A well made 8" inline fan can pull it off with slightly higher ambient temperatures, and so on.
The total cfm will be unique to each individual product and should have available to you a flow chart at various pressure differences. Those figures are the most important to determining the outcome of your desired design application. Really hope this helps you and your room design.
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so you are saying I need to match my intanke and outake fans. I want to just use a passive intake but I have to filter the air coming into the room. Basement grow and dirty air is the reason. I appreciate the informative response. For negative pressure it makes sense to me to have less coming in than going out. How much less I dont know.
OK I have been brainstorming a little about this. Can't I just filter the passive air coming in without a fan. Maybe 2 small filters that go straight into the wall with no fan. The pressure created should pull air through the filters. My only concern is that the filters will impede intake air and not enough will get through in enough time.
good for bugs and dirt. You'll have constant fresh air as long as you run the exhaust 24/7, you don't need an intake fan for this.
S
slave4sail
Mind if I stop back in worg?
Over thinking is much preferred to under thinking, but experience will be the best tool in your box.
Also, it looks like I made an error in mathematics in the initial response. 10x10x10=1000 not 100. How did that happen? I apologize for not double checking before submitting, however the rest of my comment I stand behind.
Think of your filters like this, they will in turn reduce the amount of surface area on the intake if not properly sized to the application. Surface area of the intake opening if larger than surface area of the filter will lead to loss of performance at the fan. If properly sized filter with adequate surface area is used, then the intake's surface area does not conflict with the newly added filter.
Everything works on each other. Sorry if this is difficult for me to convey, but try and focus on what physics are going on. One addition changes the dynamics of physics in the growspace, and everything in turn adjusts accordingly. This applies to a fan, intake vent, or other similar miscelaneous additions. Although all of the figures in the following article I do not preach, the gist of this article is a great read to help understand airflow.
Below are a few specific quotations that relay the information I have difficulty conveying.
"Ventilation is a general term for controlling the air quality in the growing environment. Fans are a most valuable tool, and can be better put to use with understanding the different types of fans available to the grower and where each type is best suited. The most critical fan in the growing area is often the exhaust fan. It is capable of removing heat and moisture from the grow room, as both accumulate rapidly in indoor growing situations. Indoor growers typically require an exhaust fan capable of exchanging the volume of air in the room within five minutes. A 10 wide X 10' long X 10' high has 1000 cubic feet of volume (10x10x10=1000). So, a 200 cfm exhaust fan is required (1000 cuft / 5 min = 200 cfm). This is the ideal situation. In reality, there are often several lights in this same room, and due to remote locations, static pressure from extensive ducting, and the incredible amount of heat generated, greater capacity is required. Greenhouse growers often multiply their square footage by eight to determine fan capacity for summer cooling, a requirement similar to indoor growing conditions. For example, a 10' wide X 10' long grow room would require 800 cfm fan capacity (10 X 10 X 8=800).
After determining your cfm requirements (cubic feet per minute of air flow), you will need to determine your intake requirements. As a rule of thumb one square foot of opening to the area is required for every 700 cfm of exhaust output. Otherwise static pressure (the room sucking into itself), will severely limit the exhaust output. It is not often feasible for the indoor gardener to have openings for intake air in the grow area, so intake fans are required, and greater attention must be paid to the type of exhaust fan chosen."
The Growing Environment by E.B. found in Maximum Yield January 2001 Issue
As noted before, the specific fan specifications will dictate nearly the rest of the design. In the same way that everything plays off one another in a wonderful symbiotic effect.
There is another article specifically about static pressure and intake size, however the specific volume seemed to have grown legs and walked off. Will continue to look for it, but I sincerely hope you are able to find some resolution with these comments.
Also think about the filter in the same way as the passive intake. The passive intake must be matched to have a large enough area to accomidate the pressures created by the individual unique inline fan chosen (remember specific specifications will vary). Likewise, a filter before the passive intake must also allow the same airflow so that it is not to impede the flow. Filters by design are made to capture small particles, so the reality is the area if the filter must be quite larger than an unobstructed passive intake area to maintain the same flow pattern uninterrupted. Back to searching the alternate issue with reguard to flow, static pressure, and intake size requirements. If it is found, will comment with an article summary for you.
And again, sorry about the math goof earlier. I do not want it to lead to confusion. Wonderful comment hazy lady, accurate and on point. nam myoho renge kyo
Over thinking is much preferred to under thinking, but experience will be the best tool in your box.
Also, it looks like I made an error in mathematics in the initial response. 10x10x10=1000 not 100. How did that happen? I apologize for not double checking before submitting, however the rest of my comment I stand behind.
Think of your filters like this, they will in turn reduce the amount of surface area on the intake if not properly sized to the application. Surface area of the intake opening if larger than surface area of the filter will lead to loss of performance at the fan. If properly sized filter with adequate surface area is used, then the intake's surface area does not conflict with the newly added filter.
Everything works on each other. Sorry if this is difficult for me to convey, but try and focus on what physics are going on. One addition changes the dynamics of physics in the growspace, and everything in turn adjusts accordingly. This applies to a fan, intake vent, or other similar miscelaneous additions. Although all of the figures in the following article I do not preach, the gist of this article is a great read to help understand airflow.
Below are a few specific quotations that relay the information I have difficulty conveying.
"Ventilation is a general term for controlling the air quality in the growing environment. Fans are a most valuable tool, and can be better put to use with understanding the different types of fans available to the grower and where each type is best suited. The most critical fan in the growing area is often the exhaust fan. It is capable of removing heat and moisture from the grow room, as both accumulate rapidly in indoor growing situations. Indoor growers typically require an exhaust fan capable of exchanging the volume of air in the room within five minutes. A 10 wide X 10' long X 10' high has 1000 cubic feet of volume (10x10x10=1000). So, a 200 cfm exhaust fan is required (1000 cuft / 5 min = 200 cfm). This is the ideal situation. In reality, there are often several lights in this same room, and due to remote locations, static pressure from extensive ducting, and the incredible amount of heat generated, greater capacity is required. Greenhouse growers often multiply their square footage by eight to determine fan capacity for summer cooling, a requirement similar to indoor growing conditions. For example, a 10' wide X 10' long grow room would require 800 cfm fan capacity (10 X 10 X 8=800).
After determining your cfm requirements (cubic feet per minute of air flow), you will need to determine your intake requirements. As a rule of thumb one square foot of opening to the area is required for every 700 cfm of exhaust output. Otherwise static pressure (the room sucking into itself), will severely limit the exhaust output. It is not often feasible for the indoor gardener to have openings for intake air in the grow area, so intake fans are required, and greater attention must be paid to the type of exhaust fan chosen."
The Growing Environment by E.B. found in Maximum Yield January 2001 Issue
As noted before, the specific fan specifications will dictate nearly the rest of the design. In the same way that everything plays off one another in a wonderful symbiotic effect.
There is another article specifically about static pressure and intake size, however the specific volume seemed to have grown legs and walked off. Will continue to look for it, but I sincerely hope you are able to find some resolution with these comments.
Also think about the filter in the same way as the passive intake. The passive intake must be matched to have a large enough area to accomidate the pressures created by the individual unique inline fan chosen (remember specific specifications will vary). Likewise, a filter before the passive intake must also allow the same airflow so that it is not to impede the flow. Filters by design are made to capture small particles, so the reality is the area if the filter must be quite larger than an unobstructed passive intake area to maintain the same flow pattern uninterrupted. Back to searching the alternate issue with reguard to flow, static pressure, and intake size requirements. If it is found, will comment with an article summary for you.
And again, sorry about the math goof earlier. I do not want it to lead to confusion. Wonderful comment hazy lady, accurate and on point. nam myoho renge kyoWOW. thanks so much for all the detail. I am going to use the can 150 combo- I think it is 971 cfm. my room is 700c/m 10x10x7. This should give me enough power. I read somewhere else the area of the passive intake should be twice the size of the exhaust hole. Your documented info is much more detailed. I am going to start with a 12x12 dark room vent (I would like one I can open and close as needed). If I need more I will add more but I think this is a good place to start. I am going to go with a furnace filter over the intake. It should not really impede intake very much.
Also if anyone is reading this I was going to use a seperate fan to suck air through my lights and out of the room. Most people seem to have their filter and lights combined into one. Wouldnt lights stay much cooler with outside air pulling through them rather than air from the room. In the winter I dont see this as an issue but temps in the 90s here in the summer. thanks again s4s.
Also if anyone is reading this I was going to use a seperate fan to suck air through my lights and out of the room. Most people seem to have their filter and lights combined into one. Wouldnt lights stay much cooler with outside air pulling through them rather than air from the room. In the winter I dont see this as an issue but temps in the 90s here in the summer. thanks again s4s.
thehappyguy
Member
you're going to cool your lights and your room separately? that's a fantastic idea. you could probably get away with a much smaller fan with a filter on your actual room since most of the heat being generated will be taken out by the light duct. if you cool your lights from outdoors, also, instead of the grow room like many have it, you won't have to run a filter on it and that really helps with cfm.
S
slave4sail
Anytime worg, and remember as much as the formulas and calculations help. Nothing can replace setting it up with a few days to tweak this or that, and get it dialed exactly how you like best. If I am thinking of the correct model the can 150 filter is a great choice, and has a good amount of surface area compared to the smaller versions. This will allow good airflow versus the smaller filters. This is the large, heavy, and tall filter the 150? Believe that is the one. Tall and large filter equals tall and large surface area.
As for the additional concerns you are having about where to pull from when venting the lamps, it depends on the ambient temperature of the air that you are sourcing. Be it air from outside, or from the growspace itself; the ambient temperature of that air and the rate of flow will determine which will remove the most heat from your lamps and design.
If you can vent the lamps on a separate duct run not interfering with the exhaust run for your grow space, that would be a great benefit. This will be a great ventilation design should the ambient temperatures fall within an acceptable range. Most people who utilize one duct run only for the lamps do not always have the option for sourcing additional intake from outside, I assume this is the reason for the majority of others utilizing only one duct run for the entire ventilation design.
Just a thought, but you have options that allow for quite a nice grow space. Not to pile on to your thinking plate have you ever thought about sealing the canopy area up, adding a lung room and supplementing with co2? I do not wish to overstep my bounds, and for all I know that is not in the budget. You have options afforded to you in your design and space that many others do not have access to, and I wish you the utmost positive vibes from me to you in the implementation, and execution of whichever design you end up choosing. happyguy makes great points as well.
As for the additional concerns you are having about where to pull from when venting the lamps, it depends on the ambient temperature of the air that you are sourcing. Be it air from outside, or from the growspace itself; the ambient temperature of that air and the rate of flow will determine which will remove the most heat from your lamps and design.
If you can vent the lamps on a separate duct run not interfering with the exhaust run for your grow space, that would be a great benefit. This will be a great ventilation design should the ambient temperatures fall within an acceptable range. Most people who utilize one duct run only for the lamps do not always have the option for sourcing additional intake from outside, I assume this is the reason for the majority of others utilizing only one duct run for the entire ventilation design.
Just a thought, but you have options that allow for quite a nice grow space. Not to pile on to your thinking plate have you ever thought about sealing the canopy area up, adding a lung room and supplementing with co2? I do not wish to overstep my bounds, and for all I know that is not in the budget. You have options afforded to you in your design and space that many others do not have access to, and I wish you the utmost positive vibes from me to you in the implementation, and execution of whichever design you end up choosing. happyguy makes great points as well.
thehappyguy
Member
i really enjoy all of the information you have been posting. very informative and eloquently put.Anytime worg, and remember as much as the formulas and calculations help. Nothing can replace setting it up with a few days to tweak this or that, and get it dialed exactly how you like best. If I am thinking of the correct model the can 150 filter is a great choice, and has a good amount of surface area compared to the smaller versions. This will allow good airflow versus the smaller filters. This is the large, heavy, and tall filter the 150? Believe that is the one. Tall and large filter equals tall and large surface area.
As for the additional concerns you are having about where to pull from when venting the lamps, it depends on the ambient temperature of the air that you are sourcing. Be it air from outside, or from the growspace itself; the ambient temperature of that air and the rate of flow will determine which will remove the most heat from your lamps and design.
If you can vent the lamps on a separate duct run not interfering with the exhaust run for your grow space, that would be a great benefit. This will be a great ventilation design should the ambient temperatures fall within an acceptable range. Most people who utilize one duct run only for the lamps do not always have the option for sourcing additional intake from outside, I assume this is the reason for the majority of others utilizing only one duct run for the entire ventilation design.
Just a thought, but you have options that allow for quite a nice grow space. Not to pile on to your thinking plate have you ever thought about sealing the canopy area up, adding a lung room and supplementing with co2? I do not wish to overstep my bounds, and for all I know that is not in the budget. You have options afforded to you in your design and space that many others do not have access to, and I wish you the utmost positive vibes from me to you in the implementation, and execution of whichever design you end up choosing. happyguy makes great points as well.
two things i think of:
- you could just y-split both the entrance and the exit, have smaller ducting going up to a large 6" fan and perhaps a 3 or 4 inch fan to pull through a carbon filter from the grow room. i don't know if this would cause problems, it would take experimenting, but it sure as hell would be convenient.
- if you're going to have the capability to seal off the grow room (which you do if your lights are totally cooled on a separate duct through the room) then you should go the extra mile if you can, and if you can't then in the next grow or two you can, and get co2.
I was gonna go with CO2 and seal the room but this being my first independent grow I thought I should take it one step at a time. It would also cost me an extra grand to get an A/C, bottle or generator, and CO2 meter or whatever you call the thing that measures the PPMs. If I do go the CO2 route this run I will be eating pasta for 3 and a half months. Its cool though I love pasta. Thanks happy, hazy and s4s for all your input. I am quite new here and this place rocks. I have had some free time this past week and have been trolling all day here. I have learned so much. I am going to do a soil, 3kw, scrog with 32 plants Completely legal grow. Veg for about 15 days with Lst and then flower. I will probably top depending on what strain I choose (something kushy). I think I am going to go with cutting edge nutes and maybe another one and pick the best one for my next grow. Then add another and so on to try to narrow down what works for me. BTW the 150 is the 5 foot filter with the 950cfm can which should be quite enough. I worry about odor much more than electricity. Although legal a low profile is always good. I dont want stupid cops busting in breaking all my stuff and then appologizing. Thanks again, you all rock
S
slave4sail
Your planning will make for great success. Now that you mention smell as a top concern, I would not vote with exhausting out of the window and sealing the space using co2 for the first time around. It will be much a learning experience, and less equipment to goof does not always mean less end results. One thing to suggest is planning the space according to both designs. In a way that they overlap, and when you decide to run an additional exhaust line out the window and seal it up to run co2 it will not take a total re-build. This will save much head and back aches if you decide to progress in steps, which in m opinion is the best route. co2 is a subject all it's own, and let me tell you that the benefits will never be gained unless the grower is already maximizing an environment without the addition of extra co2. It is only to be used to go beyond traditional metabolism rates, yet requires an absolute dialed environment to maintain it's effectiveness. Without sounding like an intake junkie, if adequate fresh air intake is provided there will be plenty of co2 for the plants. Adding the co2 is when that is not enough. Or to stroke ones ego, sadly myself included at times. Thanks for allowing my comments with an open mind. Treat yourself, and eat seafood and steaks. Plenty of flower clusters will still be had. Trust in it.
Do you know which reflectors you want?
3kw kushy scrog sounds all smiles
thank you for the kind words happyguy, a joy just to share our thoughts on this hobby
Do you know which reflectors you want?
3kw kushy scrog sounds all smiles
thank you for the kind words happyguy, a joy just to share our thoughts on this hobby
I was thinking the same thing, however bigger is better. I got about another month to research before I begin to build. I agree with you that CO2 is a monster unto itself and I think while my first plants are doing their thing I can get well read in CO2. I know that nothing teaches like experience so as soon as I can afford to make a mistake I will give it a try. Also great idea about shaping my room into something that will be easy to convert later when I do seal it. It is amazing all the love and thought we put into growing (or in my case getting ready to). Most of my friends have fairly below average rooms and their yields usually reflect it. Good herb but they dont seem to care about it like I do. I have high expectations of myself and I want at least a pound a light. A gram a light by my third or fourth pull. What is your method for getting big pulls? Do you choose to veg for awhile? Anyway thanks again for all the good advice slave4sail. Reflectors I read on here where somebody did some sort of footcandle measurment with three or four different kinds and the sun system super sun 2 won. Seems like as good a reflector as any I guess. I am going to use the Lumatek ballasts. The room I am gonna use already has 240 laundry outlets so I am going to rewire one of those to the four outlet timer thing. It is going to a 30amp fuse which I believe can power up to 7200 watts. I would like to keep everything around 4kw and with a big humidifier working overtime it might be a little tough but it should be somewhere close. For veg I am probalky going to only run one then maybe two MH. I like scrog because as of now I dont have anywhere to Veg. I think after this pull I will get a Jardin tent or maybe build a smaller room so I can keep it semi perpetual.
S
slave4sail
There are two ways of looking at big pulls. Pull by pull, or over a specific period of time versus another. Both are great ways to reference progress, and progress shall indeed commence! If you will please give me a moment to compose and gather my thoughts on that topic, I would be happy to share my thoughts on it. I think it's best I tread carefully as to not mix your thinking up, or sway you with any of my preferences. In a nutshell, the most important part of any method for big pulls is maintaining a schedule and sticking to the desired plan that should already be determined ahead of time, all the while leaving room for considerations to improve. None which can negatively affect above all quality or quantity. If you don't have room for a veg space, then you don't have room for a veg space. I think you do 5 or 6 pulls a year is better than 3 or 4. Time as futile the concept may be in my opinion, serves as a great indicator for progress and efficiency. More to come on this as I soak in what you have said, and try to figure what I would do in such a situation. Be forewarned, since you mention you are doing soil. My advice will lean heavily to dedicating a space for pre-veg. I assume you are sourcing cuttings from a disp.?
30x240=7200 you are correct, however it is advised you stay at or below 80% of the total load. 7200x0.8=5760watts @ 240 volts.
Section off a veg space, and you will be amazed how much can be done in relatively small spaces. This benefit in overlapping time will increase your pull per year considerably. The ss2 reflectors are great, and should do well with an average of 10 plants per lamp.
5 or 6 pulls a year is better than 3 or 4. Time as futile the concept may be in my opinion, serves as a great indicator for progress and efficiency. More to come on this as I soak in what you have said, and try to figure what I would do in such a situation. Be forewarned, since you mention you are doing soil. My advice will lean heavily to dedicating a space for pre-veg. I assume you are sourcing cuttings from a disp.?30x240=7200 you are correct, however it is advised you stay at or below 80% of the total load. 7200x0.8=5760watts @ 240 volts.
Section off a veg space, and you will be amazed how much can be done in relatively small spaces. This benefit in overlapping time will increase your pull per year considerably. The ss2 reflectors are great, and should do well with an average of 10 plants per lamp.
Ya I have to tax myself with dispensary clones. Brand new state and I dont know to many people there. I will figure out a veg space. I will have all the room in the world but really will not have the funds to build a new room for a little while. I can start to put it together bit by bit. You are so right. Saving that extra two weeks or a month is vital. While Im doing the first one I am going to get a strain that I really want from seed, germinate and choose the best female, clone and then when the first pull is done get the new girls in there. After that I should have ample time to get a veg room together. Once I get that done I can change up my growing technique and maybe add a 600w to the mix and try to go big as opposed to scrog. If my results are really good with scrog I might not change it up, it all depends and time will tell.
thehappyguy
Member
dialing in your grow space is more important and effects yield more than people think. doing a run without all the extra fancy gear will help you know what your room is like and having less things to fuck up will ultimately aid your success. once you figure out what the real working temps of your room will be, you can go from there.
scrog with many plants will probably become trying. training will take a long time, but with perseverance you can make large yields. best of luck to ya, keep it simple for the first round and then start making it more elaborate. make sure you note places where things are wrong so that you can fix them. if this means halting your future grows while you fix important things, that is better than a non-permanent "fix" that will only hold up for so long.
best of luck to ya man
scrog with many plants will probably become trying. training will take a long time, but with perseverance you can make large yields. best of luck to ya, keep it simple for the first round and then start making it more elaborate. make sure you note places where things are wrong so that you can fix them. if this means halting your future grows while you fix important things, that is better than a non-permanent "fix" that will only hold up for so long.
best of luck to ya man
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