Grow Room Fan/ Carbon Filter Exhaust Placement

[Will Rogers]

Does it matter if the fan/filter duct is at the top of the grow room?
Seems like all pictures I've seen they're at the bottom.

I know this is a weird question.
But I'm using an existing 4'' pvc pipe which was installed in the ceiling next to the water heater.
It sticks down about 18'' from the ceiling.
And I'm assuming it is there for venting if there's a gas leak per code.
So I thought keeping the vent at ceiling height would keep original purpose of vent pipe kosher.

Also, I see no reason to use the carbon filter until flowering, right?
Gunna start building my room this week.
Thanks

 

[bushmasterar15]

I have my carbon filter/fan at the top of the tent. It really depends as some strains start putting off the funk in the late vegetative stage/preflower. So I go by if I can smell it better turn it on.

 

[Baphomatt]

It's also better to have at the top for heat management. Just food for thought.

 

[Bblitzed]

Is it better to have the filter outside or inside the tent to get rid of the smell.
Setting up my first tent.

 

[Padawan1972]

My tent is a 2x4x5. It sets in a walk in closet. I went over board with size for the exhaust fan for two reasons. One, I wanted to make sure I had plenty CMF with speed control, and two just in case I upgraded to a larger tent. I initially had the exhaust fan and filter inside the tent, the typical set up. Pulling filtered air in then out to attic. I found it was taking to much headroom. I have moved the fan outside of the tent, it sits a bracket/brace I made, about a foot above tent, the 8" vent tube drops straight into the tent. I cut a hole in the ceiling and ran the rest of the tubing into attic, then attached carbon filter to end of tubing. Long story short....Iam pushing through the filter instead of pulling. Works just fine.

 

[McDee]

Does it matter if the fan/filter duct is at the top of the grow room?
Seems like all pictures I've seen they're at the bottom.

I know this is a weird question.
But I'm using an existing 4'' pvc pipe which was installed in the ceiling next to the water heater.
It sticks down about 18'' from the ceiling.
And I'm assuming it is there for venting if there's a gas leak per code.
So I thought keeping the vent at ceiling height would keep original purpose of vent pipe kosher.

Also, I see no reason to use the carbon filter until flowering, right?
Gunna start building my room this week.
Thanks

It will work either way, more to do with you needs as far as privacy. I have mine inside at the top like most I have seen. I need stealth so needs to be inside, but if you can put outside bonus room for you. I have heard that the actual filtration is better to be pulled than pushed. So take it for what it's worth, I have 0 data to back up 1 way or other. I do feel the most effective positioning is filter at top pulled out the top vent. Heat rises so must take some odor too, if it's at the bottom it is working against that. Better safe than sorry. Also the slower air passes through the filter the better. The longer the odor has contact with the carbon the more effective it is. I have same size tent as Padawan1972 and only grow auto for now so most never get high enough for it to be an issue. My filter doesn't go below lights so not a factor. I use phresh filters the work well. I get 2-3 years out of each. I only turn on when I start to smell the pre-weed smell. When it's close i go in my room and take a big whiff. If I can smell vegetation it's time lol. In the end I dont think it matters a lot, I would prefer to get them out for more room if I could.