Hello! I have an air cooled 400w HID with 6" duct openings. Air coming in will range 70-73 degrees F and pulled through a DIY carbon filter (instructions here). Exhaust will go to the attic. I have read 240 CFM inline fan will be sufficient for heat and smell while others insist I'll need 400+. I am concerned with the noise that 400+ CFM can make, and I do not have a ton of money to spend on a fan. Could someone explain why people are saying two different things, and what they personally recommend? My next question: is this carbon filter going to lessen the smell inside the room or just the smell of the exhaust air? My final question: can I connect the carbon filter directly to the hood (and chain it up of course)? I'm a little tight on space and this would be optimal. Please explain why it would be a bad idea if you feel that way. Thanks for any advice you can give. All your suggestions will be greatly appreciated
your better off having 1 exhaust for light that sux air in from outside grow area so it actually cools the light. then another for grow area with carbon filter. im using a 6 inch for about same space (450 cfm I think but on lower speed so no noise apart from air flow ofc) so yea maybe 240 cfm is plenty. im too trashed atm to do maths EDIT: the carbon filter will stop the smell outside the grow area (closet will smell, bedroom wont)
A way to calculate how much exhaust you need... Multiply your cubic feet of grow space by 4 so for you 112*4=448 Then take your total wattage of equipment in that space and divide by 4 (so for you 100) Add the 2 numbers together and that is what you need... since you are using an air cooled hood you may be able to get by with just the 448 cfm but you have to consider that attaching the carbon filter will reduce your flow by approx. 25%. I would go with at least a 6" around 450 cfm in your space.