[weeeduh]

So I have a cabinet that I am going to get cut out this week.

The inside dimensions are exactly 22"x43.5"x69"

This puts me at just over 38CF of volume of scrubbed air that I will need to move out of my cab once every 5 minutes.

This means I only need to push out 7CFM in my fan filter combo (assuming I have heat under control).

Now I haven't quite figured out the calculation yet, but this is what I am looking at getting.

https://www.htgsupply.com/viewproduct...roductID=52531

4" fan/filter 170cfm @ 80w.

That sounds like it will destroy my plants inside of 38CF! Something like swapping the air out over 4 TIMES a minute!

So I am thinking I can still use this, as long as I get one of these to change the speed of the fan.

https://www.htgsupply.com/viewproduct...roductID=53142


Sounds good right?

[FreezerBoy]

While you may want to control fan speed for sound purposes, 170 cfm in that space will do no harm. Are you sure 170 is enough?

[weeeduh]

I think the 170cfm with filter attached will be too much. I am not exactly sure how those ventilation numbers work, but just thinking about it, my main concerns for ventilation are 2 fold.

1st being the heat put off by the lights in such a small place as well as my ambient temps likely to be hitting the mid 80's.

2nd is cleaning the air. If I can control my temps with either cfl and lowering ambient temps with ac OR control with a high intensity independent aircooled hood the I am sure the 170cfm is way too much I will be growing in a 38cf cab, that means 170 cfm will exchange the air more than 4 times per minute.

If I can run the cab with lights at 5 degrees over ambient, then I will need to run ac during the day in the middle of summer, which I don't see as a problem. Just were I am setting up has no ambient ac duct.

So assuming that I am able to pull that off, with flouro's or unrestricted air cooled lights, then my next concern really is how big to make the intake holes.

I really am not sure if the 170cfm is what I am really going to get out of the combo. From what I can tell, as long as I keep my temps under control I only need to exchange the air in the cab at the cab cubic feet, which is 38cu, once ever 4-5 minutes. So I only need to push out 7-8cfm to keep the air fresh both inside and outside the cab. So I am not sure how a 170cfm rated fan/filter combo can get knocked all the way down to 8cfm.

I am also a little concerned that if I go with such an oversized solution and don't regulate the airflow, either by restricting the intake holes or slowing down the fan, that I will stunt my plants potential.

I think my math is right here, and I really hope that a combination of restricting intake and slowing down the fan will solve the oversized problem.

Thanks for the feedback FreezerBoy. I assume when you say it will do no harm you mean that I won't be creating a wind tunnel that will shock the plants. If that's the case, I'm going to just go with it, and if I have to adjust, I am sure I can adjust.

I am eager to get started, and you can only plan so much. The old saying, you study long, you study wrong comes to mind. Sooner or later, just gotta do it.

[FlaDankster]

I purchased the same unit from HTG.Just hooked it up and got all squared away yesterday.It to my surprise is doing what i wanted but my space is larger than yours,4x7x8 with a 600 as my source of light.I have central a/c to my room but without the a/c runnin temps are stayin at 78.

A bit of overkill is kinda a good thing incase you need more air flow.For your space you will def need the speed control.I can't find all my paper work i got with the fan but i beleive the 4 inch scrubber cfm is between like 145-230 or so.Maby you could use that filter with a smaller fan??.And i will say this,the fan is not very quiet so if stealth is a concern your gonna have to do some extra work to hide your noise like i did.Call HTG and speak with them,GOOD customer service they have,they will help.

[LunaShadow]

As you have a small space shouldn't you get a smaller fan?

Using that speed controller you might find you have to reduce the speed of the fan to such an extent that you get a motor humm.

Getting a smaller fan to start with or using a variac speed controller will eliminate these possible issues.

atb

[FlaDankster]

Originally Posted by LunaShadow

As you have a small space shouldn't you get a smaller fan?

Using that speed controller you might find you have to reduce the speed of the fan to such an extent that you get a motor humm.

Getting a smaller fan to start with or using a variac speed controller will eliminate these possible issues.

atb

Another thing.These fans are on the cheaper side of things so ya gotta ? how long this thing would last being turned all the way down for the majority of it's use i would assume>

[FreezerBoy]

Originally Posted by weeeduh

1st being the heat put off by the lights in such a small place as well as my ambient temps likely to be hitting the mid 80's.

Mid 80s won't kill you but, it's not optimal. Dropping temps another 10º would be better for you and that means a bigger fan. HOWEVER, bigger fans mean more noise and noise raises questions. Questions, bad. Very, very bad.

Blasting directly on the plants would be bad but, 170 cfm flowing through the cab is nothing to worry about unless it's too little air flow or too loud for the surroundings.

[weeeduh]

Originally Posted by FlaDankster

I purchased the same unit from HTG.Just hooked it up and got all squared away yesterday.It to my surprise is doing what i wanted but my space is larger than yours,4x7x8 with a 600 as my source of light.I have central a/c to my room but without the a/c runnin temps are stayin at 78.

A bit of overkill is kinda a good thing incase you need more air flow.For your space you will def need the speed control.I can't find all my paper work i got with the fan but i beleive the 4 inch scrubber cfm is between like 145-230 or so.Maby you could use that filter with a smaller fan??.And i will say this,the fan is not very quiet so if stealth is a concern your gonna have to do some extra work to hide your noise like i did.Call HTG and speak with them,GOOD customer service they have,they will help.

Thanks for the feedback, on this. Are you cooling your light and scrubbing your air in the same duct? I was thinking that if I decided to go with HID in cooltube or hood that I would go with the 6" in line duct fan from htg. Now that I think about it, that probably is a better solution!

I can get this 4" filter by itself https://www.htgsupply.com/viewproduct...roductID=49749

with this 4" in line duct fan at 80cfm. https://www.htgsupply.com/viewproduct...roductID=46434

For that matter, I don't think I would need the variable speed as at most I am looking at 2 air exchanges per minute. I could restrict this by choking off the holes if it gets to be to much air moving around. But it sounds like that is not even going to be a problem.

As far as noise, yes that is definitely a concern as well when thinking about the security of the grow. I put noise and fresh air together under security concerns.

I am pretty good with acoustics. The cab I am building is already being designed for noise insulation, so i should be good.

Thanks all for feedback, this really gives me confidence that I am going down the right track for indoor growing.

[FlaDankster]

What up weeeduh.....

Yes i am scrubbing and cooling with the same line.

For your cab bro 6 inch would be waaayy over kill just because of an HID light i think.Like i said,i'm scrubbin and cooling a 600 watt hps in a 4x7x8 space.So far it is doing fine.? is would that 4 inch scrubber(that is rated at a higher cfm than the booster fan your lookin at)going to work properly???To my understanding for things to work right the fan and filter cfm have ta go kinda hand in hand.I feel the combo you posted would do fine for you,cfl,HID don't matter.But i'm tellin ya....it's a bit loud.

[FreezerBoy]

Originally Posted by weeeduh

with this 4" in line duct fan at 80cfm.

That's a duct booster, meant to work as an aid to your real fan. Without a real fan doing all the work, it's pretty useless.