Fan and filter outside of tent?!?

Hello and thanks for reading!

Am in the process of planning my first grow and so far have a tent (2.6’ X 2.6’ X 5.2’) and a viparspectra 900w
Im now thinking about what ill need for ventilation!

What i am thinking of doing (due to small size of tent) is to have the fan and filter on the outside of the tent to save room on the inside
Is there any reason why this wouldnt work?!?
Also what way does it work best… fan blowing air through filter so duct out of tent into fan connected to filter
fan sucking air through filter, duct out of tent into filter connected to fan
does it not matter?!?!?!?!?!?!

many thanks!

Hi there!

You will get different answers on the filter set-up. I for one, believe air should Pull thru the filter. There is more scrubbing surface area on the outside of the filter than there is by pushing air out from the inside. I believe in the long run this will help the filter last longer.

However, many people push air through and it seems to work.

I think a 4" blower and filter would work for that size tent.

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Hi @Matthew420!

Thanks for the reply!

So when you say pull thru filter you mean air sucked thru filter i.e. duct to filter then fan?!?
And i take it it all being on outside of tent is ok?!?
Cant see why it wouldnt be but thought it worth asking!

Thanks again!

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Well, to do it how I like to, the filter needs to be in the tent. I like to pull air through the filter from inside the tent to the outside.

sorry to those who are sick of seeing this pic…

Air moving left to right in the pic.

If the filter is outside, you are pushing air thru the smaller inside diameter of the filter, which is much smaller.

Again, just my opinion as optimal. Many do it with the filter outside.


ok so it sounds like it works either way but inside would be optimal!
and thanks for the pic
first time ive seen it!

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In my opinion yes, that is optimal as the filter was designed to be used that way. Otherwise, they wouldn’t supply an outer pre-filter :slight_smile:

ahh so if they are designed to work that way then ill use them that way!
thanks again!

I actually built a box around my filter to seal it and still pull air through thread is from the ground up I attached both fan and filter outside grow box easily enough

so @Donaldj altho not optimal the filter still works fine on outside?!?
good to know
like said ive only got a small tent so once ive got the light in there it may have to go on the outside!

neg pressure is neg pressure if you put filter in a box and pull all air out of the box it needs to draw air from somewhere so you add inlet that inlet runs to tent just like a vac it sucks air from vent pipe very simple. Build a sturdy airtight box slightly larger than filter cut 2 holes one for duct from filter to fan one for duct to tent seal it all up and turn it on you tent will dent in and air out of fan goes through filter :wink: