Fan Size Needed for 10x10x6.5' Tent

[RandyWatsonJr]

Howdy all


Can someone assist with this one? I'm struggling to find the answer on my own. Given this tent size, and the fact I would like to fully exchange the air once every 5 mins or so (right?), what size fans will I need and what would be the proper set up?

Additional info:
I will have a carbon filter
I should not have more than one, if any, 90 degree angles in the ducting
I will not be using Co2 initially (unsure if relevant) but would like to eventually introduce it to the garden

Let me know if you need additional information to help solve this riddle

Sexual Chocolate,
Randy Watson

 

[Newty]

I run an 8" exhaust and 6" intake in a 8x4x6.5

10x10 I would use a 10" exhaust which is 1200cfm at full speed(for an AC Infinity T10 fan anyways).
If you want an active intake, 8" for the intake would be good.


Make sure the tent you get has the proper duct opening sizes for a 10".

The room the tent is going to be in, can you heat and cool it to keep temps in check during winter and summer and when lights are cranked up in flower?

 

[RandyWatsonJr]

I run an 8" exhaust and 6" intake in a 8x4x6.5

10x10 I would use a 10" exhaust which is 1200cfm at full speed(for an AC Infinity T10 fan anyways).
If you want an active intake, 8" for the intake would be good.


Make sure the tent you get has the proper duct opening sizes for a 10".

The room the tent is going to be in, can you heat and cool it to keep temps in check during winter and summer and when lights are cranked up in flower?

Thanks dood. How do you have yours scheduled to exchange the air? Is it true you want the air exchanged once every 5 mins or so? If so, does that mean the fans run 12 mins per hr in 1 min increments every 5 mins, and then shut off?

Sorry for the noob question/s but what do you mean by active intake? Like it's always active?

The room the tents are going in (I'll have 1 flower tent, 1 veg/mother/clone) is typically low 50's during the winter months and low/mid-60's in the summer months. In addition to humidifier and dehumidifier I also plan to have a window AC unit and possibly some sort of space heater or radiator.

 

[Newty]

Thanks dood. How do you have yours scheduled to exchange the air? Is it true you want the air exchanged once every 5 mins or so? If so, does that mean the fans run 12 mins per hr in 1 min increments every 5 mins, and then shut off?

Sorry for the noob question/s but what do you mean by active intake? Like it's always active?

The room the tents are going in (I'll have 1 flower tent, 1 veg/mother/clone) is typically low 50's during the winter months and low/mid-60's in the summer months. In addition to humidifier and dehumidifier I also plan to have a window AC unit and possibly some sort of space heater or radiator.

I run my fans 24/7, some people will cycle them off for 15 mins every hour. In flower you definitely want to run 24/7, no odor control if the exhaust is not running.

An active intake is when you have an exhaust fan pulling air out of the tent and a separate inline fan feeding air into the tent.
Passive intakes is what normally people use which is just running only an exhaust fan and keeping flaps at the bottom of the tent open to pull air in.

I feel I can heat and cool easier with am active intake, just my experience.

I run mine off an AC Infinity Controller 69, if temps get to warm the Contoller will raise the speeds of the fans automatically.

Example of Active Intake:

Exhaust system pulling hot air out

Intake pulling fresh air in

 

[RandyWatsonJr]

Thanks this is helpful. I'm still trying to determine the size required to exchange the air, regardless of the number of times per hour I'm looking exchange. It's also my understanding (that I don't really understand) that I need to maintain a negative pressure and this is dependent upon fan size and/or the speed in which they are running.

 

[Newty]

Negative pressure is when your tent walls suck in a little bit, to create this all you need to do it open flaps on the bottom of the tent and the exhaust fan will do the rest.

The other way to create negative pressure is to run an intake fan that's smaller/lower speed then the exhaust fan. If you were to do this I would recommend a 10" exhaust and 8" intake for a 10x10.

Either method works, the first method is more common. I use the second method.

10" inline fan with around 1200 cfm will work good for an exhaust for a 10x10 grow tent and gives you enough cfm that you don't have to run it full blast. You want a fan that has a speed contoller or better yet a temp and humidity contoller. You won't be running the fan full blast all the time, depends on temp, humidity, etc.

I prefer AC Infinity. I linked a 10" fan with controller.
There's many brands out there but I personally recommend AC Infinity.

CLOUDLINE PRO T10, Quiet Inline Duct Fan System with Temperature Humidity VPD Controller, 10-Inch

Your source to create smart growing systems with components including advance grow tents, inline fans, clip-on fans, LED grow lights, and UIS™ controllers.

acinfinity.com

 

[RandyWatsonJr]

Negative pressure is when your tent walls suck in a little bit, to create this all you need to do it open flaps on the bottom of the tent and the exhaust fan will do the rest.

The other way to create negative pressure is to run an intake fan that's smaller/lower speed then the exhaust fan. If you were to do this I would recommend a 10" exhaust and 8" intake for a 10x10.

Either method works, the first method is more common. I use the second method.

10" inline fan with around 1200 cfm will work good for an exhaust for a 10x10 grow tent and gives you enough cfm that you don't have to run it full blast. You want a fan that has a speed contoller or better yet a temp and humidity contoller. You won't be running the fan full blast all the time, depends on temp, humidity, etc.

I prefer AC Infinity. I linked a 10" fan with controller.
There's many brands out there but I personally recommend AC Infinity.

CLOUDLINE PRO T10, Quiet Inline Duct Fan System with Temperature Humidity VPD Controller, 10-Inch

Your source to create smart growing systems with components including advance grow tents, inline fans, clip-on fans, LED grow lights, and UIS™ controllers.

acinfinity.com

Bingo - this is what I was after. Thank you! I'm getting a trolmaster to monitor and control all of my environmentasl. No co2...yet.

Edit: And yeah the tents will be AC Infinity's

 

[RandyWatsonJr]

Negative pressure is when your tent walls suck in a little bit, to create this all you need to do it open flaps on the bottom of the tent and the exhaust fan will do the rest.

The other way to create negative pressure is to run an intake fan that's smaller/lower speed then the exhaust fan. If you were to do this I would recommend a 10" exhaust and 8" intake for a 10x10.

Either method works, the first method is more common. I use the second method.

10" inline fan with around 1200 cfm will work good for an exhaust for a 10x10 grow tent and gives you enough cfm that you don't have to run it full blast. You want a fan that has a speed contoller or better yet a temp and humidity contoller. You won't be running the fan full blast all the time, depends on temp, humidity, etc.

I prefer AC Infinity. I linked a 10" fan with controller.
There's many brands out there but I personally recommend AC Infinity.

CLOUDLINE PRO T10, Quiet Inline Duct Fan System with Temperature Humidity VPD Controller, 10-Inch

Your source to create smart growing systems with components including advance grow tents, inline fans, clip-on fans, LED grow lights, and UIS™ controllers.

acinfinity.com

confirming I only need a temp/humidity controller for the intake and not the outtake fan?

 

[Newty]

confirming I only need a temp/humidity controller for the intake and not the outtake fan?

If you're running both an exhaust fan (outtake fan) and intake fan, you will want a controller for each.
Depending on what controller you are going to use, some can control multiple units at once.

The reason you want one for both is because if the exhaust speed rises to get rid of heat, you want the intake speed to rise also to keep proper negative pressure.

 

[PooToe]

10 x 10 x 6.5 = 650 cubic feet of space.

You want from 1 - 3 air exchanges a minute.

You'll need a fan that can move, at minimum, 650 cfm.

I've never had the need for an intake fan other than the environment the tent is in doesn't allow me to open up the bottom flaps to let air in because of light leaks or whatever other condition doesn't allow you to be able to open the bottom flaps. I've seen setups where they use a cardboard box at each flap opening with one side open to block light and still use the bottom flaps.

The T10 says it'll move 1200cfm at full speed so at full speed you should be exchanging 2 times a minute.

You can set your controller to auto first setting up the parameters you want the tent to stay at or, set the fan to On and spend a little time dialing in the fan speed that gets you to the environmental specs range you want your tent to be at.

 

[RandyWatsonJr]

10 x 10 x 6.5 = 650 cubic feet of space.

You want from 1 - 3 air exchanges a minute.

You'll need a fan that can move, at minimum, 650 cfm.

I've never had the need for an intake fan other than the environment the tent is in doesn't allow me to open up the bottom flaps to let air in because of light leaks or whatever other condition doesn't allow you to be able to open the bottom flaps. I've seen setups where they use a cardboard box at each flap opening with one side open to block light and still use the bottom flaps.

The T10 says it'll move 1200cfm at full speed so at full speed you should be exchanging 2 times a minute.

You can set your controller to auto first setting up the parameters you want the tent to stay at or, set the fan to On and spend a little time dialing in the fan speed that gets you to the environmental specs range you want your tent to be at.

This is where my head wants to explode, thinking about all the variables and facts/opinions you find online.

A commercial grower recently told me no more than 1 full air exchange is required per 15 min increments. That's the most spaced out I've ever heard, with 1 full air exchange per 3-5 mins being the most common that I've read. You're saying 1-3 per minute which seems excessive but what the fuck do I know.

I was hoping to not having these fans running at 100% power (yet, with future potential mods) and I wasn't planning to run them 24/7. I was hoping to set them onto a timer that has them running a cycle of fresh air somewhere between 3-15 mins, probably closer to 3, OR has them running when the temp or humidity levels are rising.

Do the fans counteract each other though? For example, does the 1200cfm fan not push out as much air if at the same time, an 8 inch fan is pulling in 807cfm? Like I said, this is where my head wants to explode.

Do I only want/need one fan?!?

 

[PooToe]

I would imagine that the reason most people go with the 1 -3 air exchanges a minute is to keep as much fresh CO² in the air as possible for the girls to have at their disposal.

My setup will consist of one box fan mounted horizontally above my Bar light pointed at the roof with a couple of stationary fans under the canopy for air movement.

The idea is for the box fan to pull air from below through the air flaps, through the canopy removing moisture and gasses, past the light helping cool it and out the tent through the exhaust fan.

You don't need to run your exhaust fan 24/7 if you set it on auto and set the minimum fan speed to 0. Once the sensor shows you're within range it'll reduce the fan speed to whatever you set your minimum at. I set my minimum at 2 to make sure there is always air moving in and out of the tent.

Not sure why your commercial grower buddy is telling you that as I've worked in several licensed grow ops and they all stick to the same rule of 1 - 3 air exchanges per minute. Everyone has their preferences.

As far as fans counteracting, your exhaust will overwhelm your intake and pull whatever the physics of the air inlet diameter will let it.

Again, I don't use intake fans. I rely on the exhaust fan to pull enough through the flaps. Less fans means less things to break and buy. A 20in box fan costs around $30 and is more durable than The Terminator. A 6" oscillating fan will cost about the same and do 1/4 of the work and need to be replaced at least annually.

 

[Newty]

You're making it more complicated then it needs to be.

You only need 1 fan if you're going to run a passive system. The 1 fan would be used for exhaust.

In a 8x4, I run a 8" with 807 cfm. It runs at an average of speed 3 out of 10.

A 10" fan with 1200cfm in a 10x10 will run nowhere near full speed unless your tempatures are crazy high.

Manufacturers have been making these grow tents and equipment for years.
Manufacturer websites show 10" 1200 cfm recommendations for a 10x10.
The tents have 10" duct holes because they are meant to support a 10" fan.

 

[Newty]

As far as fans counteracting, your exhaust will overwhelm your intake and pull whatever the physics of the air inlet diameter will let you.

Again, I don't use intake fans. I rely on the exhaust fan to pull enough through the flaps.

Thats why it's important to have the intake adjust with the exhaust.

I have cfm relation to speed charts for my fans so my intake cfm is always at the proper level compared to the exhaust cfm to keep proper negative pressure. If exhaust cfm raises, my intake does automatically also.

I can't be home all the time to open more passive flaps to allow more air in if exhaust speed has to go up, this is where contol of the lung room needs to be handle well.

I gave enough info of Active systems so I'll just leave this post as my final thoughts on it and people can make the best decision for there particular setup and environmental factors.

 

[PooToe]

Thats why it's important to have the intake adjust with the exhaust.

I have cfm relation to speed charts for my fans so my intake cfm is always at the proper level compared to the exhaust cfm to keep proper negative pressure. If exhaust cfm raises, my intake does automatically also.

I can't be home all the time to open more passive flaps to allow more air in if exhaust speed has to go up, this is where contol of the lung room needs to be handle well.

I gave enough info of Active systems so I'll just leave this post as my final thoughts on it and people can make the best decision for there particular setup and environmental factors.

How do you regulate the intake in relation to the exhaust? The flaps should have enough cfm to be able to accommodate your exhaust fan at full speed.

 

[Newty]

How do you regulate the intake in relation to the exhaust? The flaps should have enough cfm to be able to accommodate your exhaust fan at full speed.

I have an ACI Controller 69 that I control both with. My 8" exhaust runs at a minimum of 3 and my 6" intake minimum of 4. If my temp hits 78, the controller automatically raises both fans 1 speed setting, if temp climbs more and reaches 80 then they both go up another speed setting. Every 2 degrees higher the temp gets, the speed of both fans increase by 1 level.

 

[Newty]

How do you regulate the intake in relation to the exhaust? The flaps should have enough cfm to be able to accommodate your exhaust fan at full speed.

Depending on tent size, your passive intake size can be to big for lower fan settings My tent has 4 big passive flaps at the bottom (bigger chance of light leaks), running all 4 open all the time with the exhaust at level of 3 is not going to be at the proper negative pressure because the intake flaps are over sized for how much air is being pulled out. I would have to either run my fan at much higher speed all the time or I would have to keep some shut to maintain the proper ratio of air coming in and out and if temp increases and the fan speed goes up, I would have to open more flaps to keep the negative pressure consistent and I can't do that when I'm not home.

Pretty much if I shut off my intake right now and open all my passive flaps, negative pressure is gone unless I crank up the speed of the exhaust fan.

 

[Newty]

Why don't you want to run the exhaust 24/7? Without it running, you can't control tempature, humidity, and you stop the exchange of fresh air.

Also important to mention there's no odor control if the exhaust isn't running because you would be sucking nothing through the filter.

If you're worried about electricity cost, it only would cost approximately $12 to run an AC Infinity 10" exhaust at max speed for 1 month but in reality you will be running it at much lower speed so it will be even cheaper.

You will see electricity cost go up a lot more from high wattage equipment such as grow lights, heaters, air conditioners, dehumidifiers, etc.

If you are worried about the noise, AC Infinity inline fans are very quiet. I have 4 AC Infinity inline fans running 2 tents in 1 room of my house and I can not hear them running, even if I'm right next to the door to the room. You can hear them when you're inside the room but you could talk to someone in person or on a phone and not even notice they are there.

There's countless different ways to setup and run grow tents, what works for 1 person might not work for another. I can only tell you what works for me and what I've learned along the way from making mistakes, researching, and getting help from others.

 

[RandyWatsonJr]

Why don't you want to run the exhaust 24/7? Without it running, you can't control tempature, humidity, and you stop the exchange of fresh air.

Also important to mention there's no odor control if the exhaust isn't running because you would be sucking nothing through the filter.

If you're worried about electricity cost

If you are worried about the noise, AC Infinity inline fans are very quiet. I have 4 AC Infinity inline fans running 2 tents in 1 room of my house and I can not hear them running, even if I'm right next to the door to the room. You can hear them when you're inside the room but you could talk to someone in person or on a phone and not even notice they are there.

There's countless different ways to setup and run grow tents, what works for 1 person might not work for another. I can only tell you what works for me and what I've learned along the way from making mistakes, researching, and getting help from others.

Honestly I’m starting to question the person who gave me the every 15 min advice regarding the fans, although maybe he meant for when/if I introduce the tents to co2? Either way, you have me convinced to run a 10” and 8” fan - the larger pulling air out.

 

[Newty]

Honestly I’m starting to question the person who gave me the every 15 min advice regarding the fans, although maybe he meant for when/if I introduce the tents to co2? Either way, you have me convinced to run a 10” and 8” fan - the larger pulling air out.

He may have been giving advice for co2, I don't run it so I can't say.

Running 2 fans is completely up to you, it's not necessary. I find it easier to control my temps and humidity with one. It's just what I prefer. You can always start with just a 10" pulling air out and see how it goes and if you need to, can add a 8" intake later.

It can become a lot when you start researching and asking questions, there's just so much information out there and everyone does things a little differently.