Grow room ventilation design. 3.5'x3'x6'

I am in the processes of building my own grow room. Looking to build a PVC frame out of 1 1/2" schedule 40 PVC then wrap it in Panda Film. It will measure 3.5'L x 3'W x 6'H. I am planning on putting a 400 Watt HPS/MH with an air cooled reflector. It is 6 inches, but I am going to put a 6" - 4" reducer on each side. Hooking this all up to a 4" can fan rated at 200 CFM which will then lead to a carbon filter and finally vent to the outside of the tent.



This is what I am planning on doing. There will be 3 vents down on the bottom to allow the tent to suck air in and up over the plants and then through the light to cool that as well.

What do you guys think? Will this be a viable option, or do I need to rethink this plan. Also how often should I be venting? I would imagine I would want some C02 build up, and the 200 CFM should clear the space pretty quickly.

I prefer to use one vent but a good one. I built custom DIY lighttraps that were modified to hold hepa filters. For the larger one I used 12x20 furnace filter the highend ones and for my smaller veg cabinet I used a Eureaka vacuume filter.

I could of easily went with a 4'inch fan as my ambient temps are low around 68-69 currently but went with the 6" for stealth factor but it does add to the cost.
Another thought is after studing your diagram I noticed you had your carbon filter between the light and the fan, while this is good as it is better to pull air through the filter than out it, the models I've seen have to be at the end of the run or the beginning. With the exception of one that is encased in a sheet metal box but there is always the DIY aspect.

I was planning on finding some window screen and cutting it up and putting several on top of one another to help with the light. I also wanted to put some kind of cover on the outside to help as well.

You may have been looking at the diagram wrong though. the flow goes like this (inlets->left side of reflector to the right->fan->filter->exhaust port) So I am not quite sure where you got the filter between the fan and the light. The 2D may have something to do with that. In 3D, or real life lol, the fan and filter would be against the back wall in at the top. The lamp will be suspended in the middle, so the fan/filter will be above and a little behind it.

Think you wanna pull thru the filter

you cannn push through the filter, but you want to pull through if you can

check out how i rigged my 2x2x5.3




works really well... temps inside stay 5F above outside of tent temps,and no smell at all... 171cfm fan, 200cfm phresh filter

Gorgeous! That exactly what I needed to see! I spent last night looking for a picture of someone who has this setup, thanks for the help! I think I am going to rig it up somewhat like yours, however I am going to mount the fan on the outside on top. Been reading that it helps with the temps because its one less thing inside the space to generate heat. How many girls do you have in that tent?

Hello, I have a question about your ventilation in the photo.
The fan is pulling air from (through) the filter, thru the reflector, and out into the tent... or outside of the tent?

Sr. Verde said:

you cannn push through the filter, but you want to pull through if you can

check out how i rigged my 2x2x5.3

works really well... temps inside stay 5F above outside of tent temps,and no smell at all... 171cfm fan, 200cfm phresh filter

Click to expand...

It's going up and out, you can see it just to the right of the fan.