exhaust fan question
- Thread starter PoeEttic
- Start date
LostInSpace...
Well-Known Member
Not sure about the size or pull, but general rule of thumb is to exchange the grow rooms air mass once every 3 minutes. Hope that helps.
curious.george
Well-Known Member
I messed around with the computer fan thing. They did not work for me. One of those 4 inch vortex fans with a fan speed controller and the fan packed in a box with foam moves like 100's of times more air and is just as quiet. I wish I had never messed with the computer fans, they don't produce any air pressure. I had substandard buds until I got good ventilation. What kind of light are you cooling?
GrowGreenGreen
Well-Known Member
If you know the CFM rating for each, then together they should move the sum of their CFMs. But then you add airflow resistance. Also a major factor: is your cab fairly airtight when closed up? Try one low for cool air intake and one high for hot exhaust. If you want positive pressure, put the higher-CFM one on the intake. Vice versa if you want negative pressure in the cab (sealing cracks is more imortant here, otherwise you'll suck in unfiltered air, which can be asking for trouble, depending on...things. Spores anyone??)
I am using CFL's and I dont have Vortex fan money. lol So computer fans, regardless of the cfm didnt work?
Exertion
Well-Known Member
Computer fans come in different streaths depending on their job... Like a case computer fan will have CFM ratings between 30-40max. Computer Power Supply fans (the ones inside the pw supply) will have CFM rating from 50-100 and we are only talking about the 80mm standard ones... As for the pull the bigger the fan the more pull it will have of course... Like the next computer fan size is 120mm and they are for the full size server computers with 3+ hard drives.. SLI graphics card setups.. and the 120mm fans have CFM rating above 100. Also im not liking ur idea to have two computer fans next to one another to try to generate more CFM's... it would not work because the fan in the back would be forcing air into the next which would over time cuz it to wareout/burn out.. They are to simple of a electronic to force to do anything really then wat they are made to do... So what I am saying here is select the right computer fan for wat u need it for... or buy a vent fan
im just going for airflow. I dont think cfls will produce enough heat to need to much heat ventilation. Will they?
Exertion
Well-Known Member
You should be fine with computer fans if you set them up right... Ventilation is not just for heat.. but also very important for the plants themselfs...
Cr8z13
Well-Known Member
Depends on how many bulbs and what wattage. I have some 42w bulbs that get kinda hot. You're best off setting up all of your lights and doing a dry run for a little while to find out how hot it gets without ventilation. If it stays below 80 you need only be concerned with airflow, in which case 1 or 2 modest output PC fans will do. If temps are well over 80-90, you need better fans.
curious.george
Well-Known Member
ok, for CFL's the computer fan should work. CFL's have the ballast included with the bulb, using tube floro's and mounting the ballast outside the box would produce less heat inside the box.