ventilation questions

Hey everyone. looking for some advice. Just got my carbon filter and need to know if my fan needs to connect directly to filter or if I can run filter to ducting to fan to ducting? any advice would be great. thanks

either, although less ducting is better when ever possible.

I have a 3x3x4 box with a 250 watt cfl and a 125 watt cfl, it is in the attic so heat is an issue, I have a passive roof intake built into the box and a 50 cfm kitchen exhaust fan, would a bigger exhaust fan help with the heat? Highs around 103 on hot days, inside box, lights off during day, and I have a normal size ossilating fan in there blowing at the lights on high

overwhelmed420grower said:

Hey everyone. looking for some advice. Just got my carbon filter and need to know if my fan needs to connect directly to filter or if I can run filter to ducting to fan to ducting? any advice would be great. thanks

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Going to start my grow soon, and I've done quite a bit of reading on this; best setup is to have filter -> fan -> duct, and elevate the filters high so it can get rid of the hot air for you. Like the person above said - less ducting is optimal, and try to have as few bends in the ducting as possible.

Have the fans suck IN the air from the filter for optimal results.

Good luck!

make sure your cfm rating is higher on your FILTER than the fan otherwise if higher on the exhaust it will pull all the air through b4 scrubbing it of unwanted odours

Dsmwarrior said:

I have a 3x3x4 box with a 250 watt cfl and a 125 watt cfl, it is in the attic so heat is an issue, I have a passive roof intake built into the box and a 50 cfm kitchen exhaust fan, would a bigger exhaust fan help with the heat? Highs around 103 on hot days, inside box, lights off during day, and I have a normal size ossilating fan in there blowing at the lights on high

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If the box is in the attic and heat is an issue, you might want to consider having proper ventilation. This means an actual inline fan - maybe 4" fan with a decent cfm count, a carbon filter, and exhaust ducting to the outside.

The oscillating fan isn't going to do much other than circulate air in the box, but at the end of the day if there isn't proper ventilation essentially you're just circulating heated air around. Fresh air intake - that's what you need.

Passive air intake is fine if you have a window in your attic, but if you don't you might need to have an intake duct as well.

Still, if you're going with CFL's alone, maybe your kitchen fan would be enough, but most grows are stealth, so its a good idea to invest in a scrubber anyway to keep the odour in.

Depends on your budget and restrictions, really.

I have carbon filter on exhaust fan so all the air is being pulled thru it, thought about a bigger exhaust fan since I don't have an intake fan, the passive intake is a 6 or 8 inch hole in the roof that's originally used for venting air from the house, house has a big exhaust fan in attic, will post pics if I can figure it out, I'm posting from my phone, where can I find a decent exhaust fan without spending an arm and a leg? And will it help out with temps enough to be worth the money? And it's not exactly a stealth grow, other than not getting busted by the authorities, the attic is my smoking area, so everyone knows I smoke up there, but they are leary about some being grown in the house so no one else gets in trouble, tho only growing 5 plants at the moment, gotta get started and get a couple mothers, got og kush and lemon skunk growing, and would it help to insulate the outside of the box so the ambient room temp from the attic doesn't affect the temps in my box? And budget is a little bit of a concern, I'm far from rich! But I will spend the money if need be and is worth it, which is why I went with high watt cfl's instead of t5's or a bunch of small cfl's, also for less heat than hps/mh lamps,

Dsmwarrior said:

I have carbon filter on exhaust fan so all the air is being pulled thru it, thought about a bigger exhaust fan since I don't have an intake fan, the passive intake is a 6 or 8 inch hole in the roof that's originally used for venting air from the house, house has a big exhaust fan in attic, will post pics if I can figure it out, I'm posting from my phone, where can I find a decent exhaust fan without spending an arm and a leg? And will it help out with temps enough to be worth the money? And it's not exactly a stealth grow, other than not getting busted by the authorities, the attic is my smoking area, so everyone knows I smoke up there, but they are leary about some being grown in the house so no one else gets in trouble, tho only growing 5 plants at the moment, gotta get started and get a couple mothers, got og kush and lemon skunk growing, and would it help to insulate the outside of the box so the ambient room temp from the attic doesn't affect the temps in my box? And budget is a little bit of a concern, I'm far from rich! But I will spend the money if need be and is worth it, which is why I went with high watt cfl's instead of t5's or a bunch of small cfl's, also for less heat than hps/mh lamps,

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If you have a carbon filter attached to the fan, then your 50 cfm kitchen fan isn't going to cut it, bear in mind the filter reduces the amount of air your fan can pull. Basically your fan is too weak for your setup - you need an inline fan for your filter to work.

If your attic already has a big exhaust fan, you should already have pretty good air circulation in your attic, although you need to make sure that the fan is powerful enough to create negative pressure and pull air through the hole in the roof.

Still, since you say the hole used to vent air from the house, it'll be located high above to vent out rising hot air - not a good position for passive intake. Passive intakes are usually located lower than exhaust ports so cool air can come in through it.

To answer the rest of your questions, yes an inline fan will help with the temperature of your cab, as well as take care of the odor issues. Very worth the money. If you set up your cab right, you'll notice a lot of difference.

You can probably find an inline fan at your local hardware store, or if you can't, you can always order one online. For your setup, you can get a 4" inline fan, BUT you gotta figure out a way to properly ventilate your setup. Your fan can pull air from one place to another, but you still have to figure out how to properly exhaust and intake fresh air.

You can find a 4" inline fan on ebay for about 60 bucks.

Insulating your box won't really work unless you ventilate your box properly, otherwise it's just going to be the same temperature as the attic air. Slightly less than ambient temps in the attic, but not by much.

Good luck, take a pic of your setup when you can, I'm sure the more experienced growers can help you with it.

Would a 6" inline fan with 160 cfm be ok in my setup or too big?

So I bought the 6 incher, 250cfm boosted, 160cfm free air, it was only 27 bucks, and the 4 incher they had was only 80 cfm for about the same price

I use a short piece of flexible duct between my fan and carbon filter. From what I have read, if the fan is connected directly the vibrations can cause the charcoal to settle and create voids where the filter will not be effective.

So here's a couple pics to see what I'm working with, hopefully this works

so im on my laptop, didnt work from phone, the square hole goes directly to the outside, fan is one i stated earlier, dont have a veg bulb for big light yet, $100 a bulb, and i already had the 125 with 6500k bulb, 250 is 2700k, thats why its up further away and off to the side as kind of supplemental lighting

My buddy is paranoid about me posting pics and that online, afraid we're gonna get in trouble, is it like the authorities are gonna read that I'm growing on here and trace my IP address and come knock down my door over a few plants?

Dsmwarrior said:

My buddy is paranoid about me posting pics and that online, afraid we're gonna get in trouble, is it like the authorities are gonna read that I'm growing on here and trace my IP address and come knock down my door over a few plants?

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Don't worry, that's way too much effort to knock a starting grow, and way too many operations to knock that way too. Can you imagine how many of us are doing what you're doing now? Having said that though, don't do anything stupid, keep it secret, and you should be fine. No tell, no smell, no sell, as they say.

If you're really paranoid, clear all the information from your photos before you post them. It's what I do. Right click on your photos under properties, and clear it manually.

That seems like a decent space to grow in, it'd probably be better to vent through that hole in the roof, and try and get a passive intake some place lower. Your lights should be just fine if you keep everything else (pH, drainage and nutes) under control. Good luck!

Dsmwarrior said:

My buddy is paranoid about me posting pics and that online, afraid we're gonna get in trouble, is it like the authorities are gonna read that I'm growing on here and trace my IP address and come knock down my door over a few plants?

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They aren't gonna do shit lol. They want warehouses full of plants.