Please Help! Ventilation Fans IN/OUT through Hydrofarm Hood

george22879

george22879

Active Member
Hello,

I have a 3x3x6 grow tent with a 400w MH. I have a 360 CFM fan that I will be using as an outtake. I want to run an intake and outtake fan. The IN and OUT duct will be run through the Hydrofarm HOOD.

My question is What CFM speed do I need for my INTAKE fan if I'm using a 360 CFM fan as my outtake?

Is the outtake fan supposed to be more powerful than the intake?

Do I also want passive intake and another outtake fan with about 70 CFM for room change as well when using this method?

Please help!
 
thedudeknows

thedudeknows

Active Member
Are you trying to cool/exhaust the tent, or just the light?

You don't need/want a fan on both ends. Ideally, pull air through the system. In your case I'd think you should simply have an open (passive) intake, and use a much smaller 4" fan to pull air through the hood, from the tent, and exhaust it outside the tent.

So the airflow would be something like:

intake inlet -> [tent air] -> [hood inlet] -> [air passes over bulb/through hood] -> [hood outlet] -> [[pulled through 4" ~150cfm fan] -> exhaust to outside

Your 3x3x6 tent is only 54ft^3. A small 4" fan rated 150cfm or so should be fine for your application including ducting through the light.
 
george22879

george22879

Active Member
thedudeknows said:
Are you trying to cool/exhaust the tent, or just the light?

You don't need/want a fan on both ends. Ideally, pull air through the system. In your case I'd think you should simply have an open (passive) intake, and use a much smaller 4" fan to pull air through the hood, from the tent, and exhaust it outside the tent.

So the airflow would be something like:

intake inlet -> [tent air] -> [hood inlet] -> [air passes over bulb/through hood] -> [hood outlet] -> [[pulled through 4" ~150cfm fan] -> exhaust to outside

Your 3x3x6 tent is only 54ft^3. A small 4" fan rated 150cfm or so should be fine for your application including ducting through the light.
Click to expand...

Thank you for your response.

Well I am really trying to cool the light. That 400w MH gets quite hot in 54 sq feet when ambient room temperature is 72-74 degrees F.

Why do you feel a passive intake through the hood is better than an intake fan duct to HOOD intake?

Is it because I get to cool the light and change room air both with 1 fan?
Is this your idea?

I will try doing what you explained and see how the temp is. I hope you are right because thats less money and hassle for me.
Should know in a few days once I get the new fan.


Thanks
 
thedudeknows

thedudeknows

Active Member
Yes that's what I was saying, and yeah it's always good to simplify.

If you have enough cool air around the tent, and enough intake surface area (equal to or greater than exhaust surface area opening), you should be good to go. If you vent this hot air to the room, expect your room temps to go up.
 
Little Tommy

Little Tommy

Well-Known Member
You could also think about adding a carbon filter into the mix as long as you are ducting. What are you doing about odor control?
 
george22879

george22879

Active Member
Well the exhaust/outtake is going into the attic. So I don't have to worry about heating up the ambient room temperature.
But other than that I have no odor control.

I want to make my own charcoal filter. Just haven't learned how to do it yet.
I definately have a powerful enough fan to do it. Just need to get the temperature and humidity under control first.

Things should be fine in a few days once I get the new fan hooked up to the hood.
Will keep you posted..
 
N

ninja12

Active Member
seen a drawing on here somewhere, showed out fan one end of hood and carbon filter the othere end. my in/out fan are the same make and size this works for me,think its with the slight restriction the filter causeson the out fan.
 
thedudeknows

thedudeknows

Active Member
Real nice. Like duder above said, put the carbon filter on the other flange on the hood and you should be golden. You may not have much smell to worry about though if it eventually vents out the attic above everyone.
 
george22879

george22879

Active Member
Thanks for the advice guys.

I've been having much better results with the current setup. With the new fan, a filter, housing for ballast, some tweaking and I should have a stable environment.
 
You must log in or register to reply here.
Top