Grow room design - Ventilation

T

TowelieMan

New Member
Hi all,

I'm a newb, looking for some advice on how to keep my room temp and humidity regulated. I'm currently installing a floor in the attic. I have about a 16'x12' room but only part of that is full standing height (6') since you run into the roof. I have 2 A/C registers delivering air into the space. Here's a pic:

Plants_5_5_13 586.jpg
Right behind the camera, there's currently a 7.5" exhaust fan venting the attic. We've already had a couple of 90+ degree days this year and without insulation up there yet, the fan and cool air only kept it in the upper 80's. I'm thinking about building a smaller room within this one that will be easier to control. I need to insulate the whole attic but can't use much of the space and want to isolate the grow room from general crappy things in the attic, am I correct?
Any feedback welcome. If you had a virgin attic, how would you set it up? I'm only looking to grow small-ish crops for now (10 plants?)
Thanks!
 
S

silasraven

Well-Known Member
ten sounds good 600 watt or 1 300 watt LED for the temps issue. grab 6 inch inline fans maybe 3 for the space and set them up with 2 intaking air from outside. find a small air filter and just make a box for it to pull the air from outisde in. mylar will be thebest thing you can do for the grow besides tons of fans and intake from the outside.
 
Friendly Caregiver

Friendly Caregiver

Well-Known Member
Build one of these on your roof. It looks like you are more than capable of handling the construction. Here is the link, it might be choppy.

http://www.lulusoso.com/products/Industrial-Roof-Exhaust-Fan.html

With this room, you have to remember one thing. Remove the heat from the reflectors you are using as soon as possible. Don't have it bend in all sorts of directions, and going through multiple lights to end up exhausting into another room. Go straight out of the ceiling, and keep the duct as short as possible.
 
A

AMCRambler

Member
I would be really worried about heat in an attic in the summer. I would think the best way to do this would be to build a smaller room EXTREMELY well insulated with your AC units cooling that smaller space. I would also worry about the heat signature up on that roof with infra red cameras on helecopters.

Best of luck!
 
C

contraptionated

New Member
Whatever ventilation scenario you choose, always use passive intake (no intake fans...ever). For example, if you had one 6" exhaust fan pulling air out of the room you would use at least 4x the circular mil area of that fan in the form of a hole (no fan blowing in). The reason why forced intake is not necessary and also a possible "Welcome To Jail" card is because if the exhaust fan craps out and the intake fan doesn't you will create a tremendous amount of positive pressure and you will definitely leak odors outside. Passive intake will also insure a negative pressure environment which is one of the features you need to prevent heat from escaping which would in turn make the windows of your house glow when viewed with infrared cameras. Infrared heat guns from squad cars will also be able to detect you. If you expel the heat fast enough ( I use a 10" can fan with a can filter 150 blowing through a horizontal duct with no bends, 20 foot run for every 1200 watts of lamps and it has worked perfectly for me) you still need to line the room with an extremely low density insulation with the ability to scramble infrared frequency. I will suggest to only use 2 layers of 3/4" thick white polystyrene foam board with reflective Mylar coating. It's called Polyshield and its sold at Home Deep and its sold in 4' x 8' sheets. Keep the room as detached from the attic walls as possible. Think Magnetos prison at the end of the first X-Men movie. Also, provide a raised floor for the air to circulate through a multitude of floor perforations ( in the form of 1/4" holes, many thousands depending on how much exhaust, remember to equal at least 4x the circular mil area of the exhaust) . Because you are in an attic you would never exhaust straight up and out of the roof directly from the ceiling space in the grow room because light will definitely escape so instead make holes up top and out of a sidewall (4x the area of the exhaust port) and then in an area within the attic but made to be completely dark, you can setup a can filter combo in a vertical position to blow straight up and out of the roof with a special roof cap that prevents water leaks. But remember, strange exhaust openings on your homes exterior can attract the attention of rats or law enforcement. I have a super stealth way of exhausting outdoors but I will never tell. P.S.The raised floor idea is in fact the penultimate venting/cooling method. It provides the most even bottom to top air circulation while constantly replenishing new air directly to the undersides of the leaves , exactly where the stomata need it.
 
Southernhempshire

Southernhempshire

New Member
If you use passive intake,don't you find your just sucking in the hot air thats in the attic space? (About 40 c here)I did and had to get a intake fan rigged,sucking air in through the ceiling of a spare room,so its cooler temp.
id insulate your attic space then build a simple room,then insulate that again.double bubble foil works well,and cheap to buy.
have your filter at a high spot within the room,then you can just suck out into the attic space with no worries about smells leaching outside. Im against directly blowing air out of vents,chimneys etc as it creates a obvious heat signal
In the hottest months i can keep the inside of the grow space a steady 26-28c while the attic space gets up to 40c
using a fan controller will allow you to keep neg pressure at all times,one with temperature probe helps,just set your max temp and leave it to it.
Best of luck.
 
C

contraptionated

New Member
Southernhempshire said:
If you use passive intake,don't you find your just sucking in the hot air thats in the attic space? (About 40 c here)I did and had to get a intake fan rigged,sucking air in through the ceiling of a spare room,so its cooler temp.
id insulate your attic space then build a simple room,then insulate that again.double bubble foil works well,and cheap to buy.
have your filter at a high spot within the room,then you can just suck out into the attic space with no worries about smells leaching outside. Im against directly blowing air out of vents,chimneys etc as it creates a obvious heat signal
In the hottest months i can keep the inside of the grow space a steady 26-28c while the attic space gets up to 40c
using a fan controller will allow you to keep neg pressure at all times,one with temperature probe helps,just set your max temp and leave it to it.
Best of luck.
Click to expand...
Just because I suggested the utilization of passive intake doesn't mean that the intake holes would need to be fed from the attic. Matter of fact, I suggested raised floor passive intake, so where do you think the air would be fed from? The ceiling below could easily be used ...I never said it couldn't and in fact that is exactly what I implied (I did mention the use of a raised floor passive intake and never made any mention of sucking air from the attic). I did mention bottom to top airflow so the pulling of air from the ceiling of the room below (through the raised floor) is more than just implied. It is obvious. Also, why would passive intake neccessarily mean pulling air from the attic?
 
Southernhempshire

Southernhempshire

New Member
No prob,all good then.
Just got lost in your reply.
I wasnt saying your wrong,just questioning what i read,simples....
wrap one up and relax.
 
justugh

justugh

Well-Known Member
can i ask u.........do u see the plumbing vent pipe.............if u have access to that run your exhust to that and let it vent out the top of the house .......just keep pressure blowing out of the grow room and u will be fine

lucky bastard if i could tie into that pipe i would not need carbon scubber .............it is a vent pipe for the plumbing in the house when u flush toilet the air bubbles this is were all the gases exit ..........the green room gasses would mix in and u could not see a thing ....if u got dank u might smell it on the outside out house none windy damp days .......but looks like u are in a 2 maybe 3 story house every 20 feet off the ground the wind is blowing 10 mph faster so if it is 6 on ground up there it is 16
 
WeeGogs

WeeGogs

Active Member
contraptionated said:
Whatever ventilation scenario you choose, always use passive intake (no intake fans...ever). For example, if you had one 6" exhaust fan pulling air out of the room you would use at least 4x the circular mil area of that fan in the form of a hole (no fan blowing in). The reason why forced intake is not necessary and also a possible "Welcome To Jail" card is because if the exhaust fan craps out and the intake fan doesn't you will create a tremendous amount of positive pressure and you will definitely leak odors outside. Passive intake will also insure a negative pressure environment which is one of the features you need to prevent heat from escaping which would in turn make the windows of your house glow when viewed with infrared cameras. Infrared heat guns from squad cars will also be able to detect you. If you expel the heat fast enough ( I use a 10" can fan with a can filter 150 blowing through a horizontal duct with no bends, 20 foot run for every 1200 watts of lamps and it has worked perfectly for me) you still need to line the room with an extremely low density insulation with the ability to scramble infrared frequency. I will suggest to only use 2 layers of 3/4" thick white polystyrene foam board with reflective Mylar coating. It's called Polyshield and its sold at Home Deep and its sold in 4' x 8' sheets. Keep the room as detached from the attic walls as possible. Think Magnetos prison at the end of the first X-Men movie. Also, provide a raised floor for the air to circulate through a multitude of floor perforations ( in the form of 1/4" holes, many thousands depending on how much exhaust, remember to equal at least 4x the circular mil area of the exhaust) . Because you are in an attic you would never exhaust straight up and out of the roof directly from the ceiling space in the grow room because light will definitely escape so instead make holes up top and out of a sidewall (4x the area of the exhaust port) and then in an area within the attic but made to be completely dark, you can setup a can filter combo in a vertical position to blow straight up and out of the roof with a special roof cap that prevents water leaks. But remember, strange exhaust openings on your homes exterior can attract the attention of rats or law enforcement. I have a super stealth way of exhausting outdoors but I will never tell. P.S.The raised floor idea is in fact the penultimate venting/cooling method. It provides the most even bottom to top air circulation while constantly replenishing new air directly to the undersides of the leaves , exactly where the stomata need it.
Click to expand...
don't listen to this idiot, use an exhaust fan 1 size higher than your intake fan we need to get lots of cool air in the room with lots of c02 in it, I take it they do not sell heaters in your country you idiot, I use a 12" exhaust and an 10" inlet but my room is exhausting very high up on the roof in a block of flats so no carbon filter is needed. if I was using a carbon filter I would have to go 2 sizes bigger as the filter puts a stranglehold on the exhaust fan so I would use a 12" exhaust and an 8" inlet that way negative pressure is maintained if we all worried about fan failure we would not be growing in the first place and passive intakes are ok for a computer grow or some tiny grow like that not a large room with lots of plants.
 
C

contraptionated

New Member
The exhaust pulls it in and pushes it out all at the same time. Negative pressure is achieved by not going over 5X ( approximately) of your exhaust port or in the case of a properly enlarged exhaust port as per manual D of ACCA you would go about 2X as large on the passive intake holes as the size of the exhaust. How is saving electricity and getting the same result idiotic?? Plenty of people understand passive intake , the problem is that you don't. It works very well for me and chances are you don't have 18Kw of light so you don't know how well passive intake works on a grand scale. Until you speak from experience( and I've been there and done that with every known method of growing and ventilation) you can't hang. Why would the ACCA manuals suggest passive intake in the first place if it didn't work. Do you even know what an ACCA manual is??
 
C

contraptionated

New Member
Whether or not the carbon filter puts a stranglehold on the exhaust, it would never help to put an intake fan. How does an intake fan improve the performance of an exhaust fan you moron!!
 
C

contraptionated

New Member
Negative pressure is not maintained efficiently with an intake fan. It is done efficiently by knowing how to size your passive intake according to the exhaust parameters. If you don't know how to do that without wasting electricity go learn something and read manual D of the ACCA then talk to me when you know what your talking about. The possibility of an exhaust fan crapping out is only one of the reasons why passive intake is better. You can keep believing what you believe and wasting that electricity to compensate for your lack of knowledge. P.S. The carbon filter will always put some type of a "stranglehold" on the exhaust. It is not remedied with an intake fan, it is remedied by enlarging the duct on the outflow of the exhaust you idiot!! That 8" intake fan to feed the 12" exhaust would draw about 260-280 watts of electricity costing 30 bucks more per month ( approx. depending on utility rates) if on 12 hrs./day and twice as much for 24/7 runtime. Lets call that extra fat on your electric bill an "idiot tax" for not knowing how to do passive intake.I base my advice on ANSI recognized reference literature and you base your advice on an inefficient method for the sake of paying more on your electric bill and creating more noise ( extra blowers make extra noise) that would need a silencer to quiet down. I use the least amount of air blowers to achieve the same result (you use 2 and I use 1) and I'm the idiot?????
 
jrainman

jrainman

Active Member
Ok So first thing ,Do not Tie in to your Plumbing Vent , if you induce your vent with air pressure , your drains will not work properly and or your house will smell like shit.

I would offer you advice ,but when doing a attic build ,I would need to know the Most important thing witch is how your house is vented , They are 2 types of house venting 1) is called gable venting= this is when you have vents ( grills on either side of your attic ) the 2) is called Ridge vent =a ridge vent is just that where the 2 roofs meet at the top of the roof (ridge) it will be vented 70-90% of the ridge line.

Like I said I would offer advise ,but you need to understand how a house (structure ) breaths before you can give the proper advice. A house need to breath properly by just adding exhaust and intake air you can effectively cut the life of your house , your roofs life span will be greatly reduced along with the framing structure of the house.

not doing this properly will also have a great effect on the efficiency temps of your entire house.( R value reduced)
 
HappyMan420

HappyMan420

Well-Known Member
AMCRambler said:
I would be really worried about heat in an attic in the summer. I would think the best way to do this would be to build a smaller room EXTREMELY well insulated with your AC units cooling that smaller space. I would also worry about the heat signature up on that roof with infra red cameras on helecopters.

Best of luck!
Click to expand...
run your lights at night in the summer.

-HM420
 
C

contraptionated

New Member
HappyMan420 said:
run your lights at night in the summer.

-HM420
Click to expand...
That would only make it easier for thermal imaging (via helicopter) to detect you because of the increased heat differential between the outside temps and the inside of your grow, but I do implore the person who opened the thread to rely on Jrainman for ventilation advice. Jrainman respects the ANSI recognized ACCA Manual D ( it is apparent in all the advice he gives on proper duct sizing). He also knows that passive intake is a viable option ( that is implied because he never argued my ideas on passive intake, whether or not there are so many other ways to vent/ cool a grow space and whether or not he agrees on my unconventional methods 100%).To the person who started the thread: be happy that Jrainman entered the discussion, now pick his brain while he is showing interest before its too late.
 
C

contraptionated

New Member
WeeGogs said:
don't listen to this idiot, use an exhaust fan 1 size higher than your intake fan we need to get lots of cool air in the room with lots of c02 in it, I take it they do not sell heaters in your country you idiot, I use a 12" exhaust and an 10" inlet but my room is exhausting very high up on the roof in a block of flats so no carbon filter is needed. if I was using a carbon filter I would have to go 2 sizes bigger as the filter puts a stranglehold on the exhaust fan so I would use a 12" exhaust and an 8" inlet that way negative pressure is maintained if we all worried about fan failure we would not be growing in the first place and passive intakes are ok for a computer grow or some tiny grow like that not a large room with lots of plants.
Click to expand...
Also... I would never use a heater. That takes more power...idiot!! I recycle heat from taking in air from an adjacent room that has the lights on while the room that has the lights off( which needs the heat) passively takes it in. So you waste power on heaters and intake fans you moron!!! I don't need any of those things. Your total gpw efficiency ( including all the power you use , not just the wattage consumed by lights) must be abysmal. You picked a fight with the wrong Jedi Knight.
 
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