venting, smell and heat question

closet grow (2x7x7 size) I need to put venting into the closet. Will be installing inter and exit with 2- 4 inch inline duct fans. In the south its about 100 degrees in the attic during the summer months. I am considering installing the pull air in the bottom of the closet from the house for a/c cooled air vs pulling from the attic. The exit will go to the attic. Will the smell exit into the house from the fan vent pulling air into the room? suggestions? I am using a carbon filter for exit into the attic duck fan.

Relaxed said:

closet grow (2x7x7 size) I need to put venting into the closet. Will be installing inter and exit with 2- 4 inch inline duct fans. In the south its about 100 degrees in the attic during the summer months. I am considering installing the pull air in the bottom of the closet from the house for a/c cooled air vs pulling from the attic. The exit will go to the attic. Will the smell exit into the house from the fan vent pulling air into the room? suggestions? I am using a carbon filter for exit into the attic duck fan.

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bump for the Friday crowd....Here is the vent....http://www.htgsupply.com/viewproduct.asp?productID=46434

If you just use a passive intake or very small cfm fan from you home ambient air like described, and your exhaust fan is a good CFM rating, then you creat a negative pressure space and the air will not be able to leak back into your home, hence there should be no odor... That fan there would be perfect to draw air into your room, at 80 CFM, I would recommend a fan of about 400-600CFM to draw air out of your room.

I assume that you are using a carbon filter on the exhaust?

As stated as long as you have enough negative pressure you won't get air coming back into your living space.

I bought the same fan for both enter and exit. Think it's too late to change the order in shipping to an exit 6 inch fan. Money is a concern at the moment....

Then it will definately leak into your home. The exitting CFM has to be at least tripple the entering CFM... When you take into account the size of your room plus adding a Carbon filter, your exitting CFM will be about 40, and then entering at 80. You are going to be in a positive pressure situation. You will not really be drawing in much air, insead, air will be pushed out of every corner of your grow room causeing leaks of odor like crazy. You need a venting fan of at least 400-600CFM to be in a good negative pressure situation...

Relaxed said:

I bought the same fan for both enter and exit. Think it's too late to change the order in shipping to an exit 6 inch fan. Money is a concern at the moment....

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you want inline fans, not booster fans. those things are totally useless to move stagnate air.

bleezyg420 said:

you want inline fans, not booster fans. those things are totally useless to move stagnate air.

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Agreed, the one for intake is fine, but for exhause get a can fan, inline, or vortex... 2X7X7 way too big for a tiny booster fan....

Guess I'll enter and exit to the attic for no smell in the house for now. Deal with the heat for a season till the job front improves. Way over budget already.....thanks

Glad I didn't start cutting into the house yet. That's about $120 bucks more.

Relaxed said:

closet grow (2x7x7 size) I need to put venting into the closet. Will be installing inter and exit with 2- 4 inch inline duct fans. In the south its about 100 degrees in the attic during the summer months. I am considering installing the pull air in the bottom of the closet from the house for a/c cooled air vs pulling from the attic. The exit will go to the attic. Will the smell exit into the house from the fan vent pulling air into the room? suggestions? I am using a carbon filter for exit into the attic duck fan.

Click to expand...

For a relatively small grow space you are really put some good thought. Glad you are adhering to simple concepts of air flow..heat rises and cold air lingers to the bottom. You might want to look into 6 inch inline fans to pull and push more cfm's. Good luck with your grow.