uraceulose
Member
For those running cool air from outside to inside or your room or tent...how are you filtering the air to keep bugs/pests/dirt OUT?
Thanks so much for any ideas,
Thanks so much for any ideas,
-
Happy Birthday ICMag! Been 20 years since Gypsy Nirvana created the forum! We are celebrating with a 4/20 Giveaway and by launching a new Patreon tier called "420club". You can read more here.
-
Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!
How to filter intake?
- Thread starter uraceulose
- Start date
Well panty hose over the end of the duct will help filter bugs and dust but your main concern should be mold.
You need a Phresh Intake Filter
http://www.youtube.com/watch?v=iAGu9Mc7g6g&feature=player_embedded
You need a Phresh Intake Filter
http://www.youtube.com/watch?v=iAGu9Mc7g6g&feature=player_embedded
yerboyblue
Member
Just run a cheap filter like the panty hose. I use either a piece I cut from the wrap that comes on carbon filters, or the cheapest filters I can get at home depot and cut them and tape it over the intake side of the fan, preferably on the outside so nothing is in your ducting. Replace it every run.
To filter the outside air that cools my lamps I used screws, caulk, and plywood to make a sealed box with a medium duty pleated AC filter in it. I used 2x2 to make precise fitting rails so air can't get around the filter. Used studs and wingnuts for the face side for access. Face has simple foam weather stripping [adhesive back] to seal it. Works well, filters last about a month. Ducts enter on one side of filter box, exit on other side. You could use a more aggressive filter, but will have to compensate for reduced air flow and fan strain. Good luck. -granger
DIY is how I did it--homemade filter box.
Home Depot has 1 1/2" thick styrofoam boards (4'x8') for less than $10, they also have 12" square HVAC filters for about $4...and a tube of glue (for styrofoam) for about $5.
I built a box, about 24" long and about 15" wide/tall such that...the 12" filter is secured in the middle with two 6" holes at opposite ends. I ran rigid duct from roof eaves to the box (cold "unfiltered" air) and rigid duct to the environment ("filtered air"). The fan is located at the very end of the duct work and "pulls" the air from outside, through the filter and into the room.
I change filters every 2-3 months and the night air cools BOTH my lamps (hoods are barely warm to the touch) and the environment (air conditioner runs about 25% of the time when lights are on, rarely when lights are off).
I save a few benjamins each month since I use less electricity and use less canned CO2 (outside air has CO2...and its free).
Cheers!
Home Depot has 1 1/2" thick styrofoam boards (4'x8') for less than $10, they also have 12" square HVAC filters for about $4...and a tube of glue (for styrofoam) for about $5.
I built a box, about 24" long and about 15" wide/tall such that...the 12" filter is secured in the middle with two 6" holes at opposite ends. I ran rigid duct from roof eaves to the box (cold "unfiltered" air) and rigid duct to the environment ("filtered air"). The fan is located at the very end of the duct work and "pulls" the air from outside, through the filter and into the room.
I change filters every 2-3 months and the night air cools BOTH my lamps (hoods are barely warm to the touch) and the environment (air conditioner runs about 25% of the time when lights are on, rarely when lights are off).
I save a few benjamins each month since I use less electricity and use less canned CO2 (outside air has CO2...and its free).
Cheers!
CannabisTHC
Member
Horti-Control Dust Shroom, its a Hepa filter which removes everything down to .1 micron. I use one for my air cooled lights and the other for intake. I couldn't imagine not using them.
uraceulose
Member
Thank you all so much!
I will post back later this evening with an idea for a box/intake using most of these ideas
I will post back later this evening with an idea for a box/intake using most of these ideas
uraceulose
Member
So how do those boxes work?
That's the way I think I need to go.
Run one duct from the window into a box with holes on either end. Then in the middle of the box put a filter.
Have the duct run into one side of the box then out the other and into the tent?
Then have a separate exhaust duct with no box, just a filtered duct running on a fan through a filter at the end.
Thinking that an 800 cfm exhaust with a 440 cfm intake should be pretty good ?
I will also obviously have circulation running.
Please lemme know what you guys think
That's the way I think I need to go.
Run one duct from the window into a box with holes on either end. Then in the middle of the box put a filter.
Have the duct run into one side of the box then out the other and into the tent?
Then have a separate exhaust duct with no box, just a filtered duct running on a fan through a filter at the end.
Thinking that an 800 cfm exhaust with a 440 cfm intake should be pretty good ?
I will also obviously have circulation running.
Please lemme know what you guys think
Visualize a box, 24" long, 15" high, and 15" deep with a lid. Open the lid and in the middle is a slot (made from styrofoam scraps) that holds securely a normal HVAC filter that is 12x12x1. I use 6" ducting, so at each end there are two 6" holes. I bring fresh air from under the eaves of my house...which meets my security and environment needs. The filter is LESS THAN $4.
Using a 3.5x10x6 "HVAC boot" (metal connector that has a 3.5"x10" rectangle opening at one end and 6" round opening at the other) made my job easier and somewhat stealth--the cover to hide the 3.5x10 cutout I made and very easy to run round 6" ducting. The grill covering the 3.5x10 cutout...kinda matches the house's original attic vents; hard to tell the difference between the ones 20+ years old and one I made a few years ago. Sooo, cool outside air is drawn in through the "stealth attic vent"...through the filter box (cheap filter)....and then out (free of bugs, dust, critters, etc). To improve system efficiency--where possible use rigid duct instead of flex ducting ...including elbows attaching to the lamp hoods (rigid ducting has less air friction...meaning your fan can do more with less).
I also exhaust air 24/7 in veg...(no CO2) and in the flower--once every 2 hours for 20 min or so (when lights are off...bottled CO2). I live in So Cali, a few miles from the ocean and I have NO AC in veg (4-400w MH) and my temps range 69-83 degrees with a few spikes to 90 degrees during the heat wave (100+ outside...no issues). RH is 40-60--depends if it is raining or not. My flower temps range 72-81 and the AC runs about 15 mins/hour or so when lights are on...never 24/7, and hardly ever when lights are off.
BTW...use insulated ducting (flex or rigid) when you duct fresh air to your first lamp, condensation around the ducting will occur (cold outdoor air meeting warm indoor air) and why create a breeding ground for mold? Imagine that....air that is too cold that it causes water to drip from ducting and lamp housing. Yep...insulate the "cold intake" side of your ducting inside your growing environment to avoid water drippage issues.
Cheers!
Using a 3.5x10x6 "HVAC boot" (metal connector that has a 3.5"x10" rectangle opening at one end and 6" round opening at the other) made my job easier and somewhat stealth--the cover to hide the 3.5x10 cutout I made and very easy to run round 6" ducting. The grill covering the 3.5x10 cutout...kinda matches the house's original attic vents; hard to tell the difference between the ones 20+ years old and one I made a few years ago. Sooo, cool outside air is drawn in through the "stealth attic vent"...through the filter box (cheap filter)....and then out (free of bugs, dust, critters, etc). To improve system efficiency--where possible use rigid duct instead of flex ducting ...including elbows attaching to the lamp hoods (rigid ducting has less air friction...meaning your fan can do more with less).
I also exhaust air 24/7 in veg...(no CO2) and in the flower--once every 2 hours for 20 min or so (when lights are off...bottled CO2). I live in So Cali, a few miles from the ocean and I have NO AC in veg (4-400w MH) and my temps range 69-83 degrees with a few spikes to 90 degrees during the heat wave (100+ outside...no issues). RH is 40-60--depends if it is raining or not. My flower temps range 72-81 and the AC runs about 15 mins/hour or so when lights are on...never 24/7, and hardly ever when lights are off.
BTW...use insulated ducting (flex or rigid) when you duct fresh air to your first lamp, condensation around the ducting will occur (cold outdoor air meeting warm indoor air) and why create a breeding ground for mold? Imagine that....air that is too cold that it causes water to drip from ducting and lamp housing. Yep...insulate the "cold intake" side of your ducting inside your growing environment to avoid water drippage issues.
Cheers!
uraceulose
Member
Thanks so much.
That's what I'll do...
Going to buy a piece of polycarbonate and put it right in the window inside of the window screen. Just open the window about 10-12 inches...it's a sliding left to right type casement window.
Then seal the polycarbonate around the edges..cut a circular hole in the lexan/poly sheet. Mount the round ducting to the lexan then down into the box.
The only thing I'm a little hung up on is how big of a box/filter I will need. It seems as though a 20x30 inch or 20x40 inch would support 750-800 cfm? That's a little large but will still work if it's what I gotta do.
Hopefully this will keep cool w/o an aux (portable) AC..
That's what I'll do...
Going to buy a piece of polycarbonate and put it right in the window inside of the window screen. Just open the window about 10-12 inches...it's a sliding left to right type casement window.
Then seal the polycarbonate around the edges..cut a circular hole in the lexan/poly sheet. Mount the round ducting to the lexan then down into the box.
The only thing I'm a little hung up on is how big of a box/filter I will need. It seems as though a 20x30 inch or 20x40 inch would support 750-800 cfm? That's a little large but will still work if it's what I gotta do.
Hopefully this will keep cool w/o an aux (portable) AC..
Ura,
If possible, make it easy on yourself and use a filter that is available at the grocery store. Because of space, etc., I had to use an 18x18 which I can only get locally at W.W. Grainger. Not a huge PITA, but inconvenient.
I'm confused about what you said about 440cfm intake and 800cfm exhaust fan. To avoid putting a lot of strain [shortening fan life] you need twice the sq in of intake as exhaust. I don't see how a 440cfm fan can supply an 800 cfm fan without problems. I would use the 800 and just have passive intake of about 75 sq in. That would be 7.5" x 10", or 8x9.5, etc. Good luck. -granger
If possible, make it easy on yourself and use a filter that is available at the grocery store. Because of space, etc., I had to use an 18x18 which I can only get locally at W.W. Grainger. Not a huge PITA, but inconvenient.
I'm confused about what you said about 440cfm intake and 800cfm exhaust fan. To avoid putting a lot of strain [shortening fan life] you need twice the sq in of intake as exhaust. I don't see how a 440cfm fan can supply an 800 cfm fan without problems. I would use the 800 and just have passive intake of about 75 sq in. That would be 7.5" x 10", or 8x9.5, etc. Good luck. -granger
uraceulose
Member
What I meant is that the formula for intake/exhaust is based on a passive intake.
When using a forced intake you don't need as much area..
When using a forced intake you don't need as much area..
uraceulose
Member
Thanks. I was under the impression that it's not so much the CFM rating of the fan but rather the SIZE of the intake holes that mattered.
Instead how should I setup the intake and make sure it's enough to flow the 800 or so CFM I'll need to swap the room air twice per minute?
10 x5 x 7 tent = 350 cubic feet
I figure a 10 inch inline 800+ CFM for exhaust BUUUUUT then I have to add a filter to keep bugs out. I came up with a 20x40 filter to keep flow from being very restricted.
So, I'll have to run the exhaust duct out into a box with a 20 x 40 inch standard home filter then out the other side of the box and up into the attic?
Now for the intake...I'd again need to run a 10 inch duct with no fan (this time the duct will run straight from the window to the intake box)...then have the same size filter/box or twice as much?
What I'm worried about and don't quite understand now is the theory behind passive vs. forced intake...
The passive is fairly simple in the calculation but it will take a HUGE intake box to (2) 20 x 40 inch filters inside of an intake box...in order to double the area of the intake filters.
To take it a step farther and I'm probably over complicating this...the reason I think I need the 20 x 40 filter for the EXHAUST is because according to what I've read that's what it takes to flow roughly 800 CFM. If I turn the fan all the way up..it should be pulling about 800 CFM out of the tent as exhaust...
So it will need to flow at least 800 CFM through the intake to keep up with the exhaust. BUT I don't think I need 1600 CFM capability as far as intake...?
I mean if there is exhaust being expelled through a 10 inch diameter duct on an inline fan flowing 800 cfm...and you leave a passive intake just (2) 10 inch filtered ducts open with no fan just straight to the window....will that be enough?
Should I add a fan for intake?
Thanks and sorry to be so long winded...also I have read through the ventilation 101 sticky along with the other stickys.
Take care and thanks again for any advice
N
noyd666
Ura,
Pheeew. Let's see. I wouldn't worry so much about the sq in of the filter and box. What really counts is the number of sq in of intake, to supply the sq in of exhaust without cutting flow much. A 10" exhaust is [pi r squared] about 78 sq in. Rule of thumb which is frequently pointed to in Ventilation 101, is twice the sq in of passive intake as exhaust. That would be 150ish, or 10x15, 12x13, 2-10" round, etc.
You may want to add some sq in to compensate for the filter resistance. I believe you only need about the same number of sq in of filter as intake. You can go bigger if you want, but I wouldn't go much bigger.
If you want to go with an intake fan, you'll need the same size as exhaust fan, depending on what's between them. Passive should work fine, without the unknowns [to me] of using an intake fan. Less cost too. Good luck. -granger
Pheeew. Let's see. I wouldn't worry so much about the sq in of the filter and box. What really counts is the number of sq in of intake, to supply the sq in of exhaust without cutting flow much. A 10" exhaust is [pi r squared] about 78 sq in. Rule of thumb which is frequently pointed to in Ventilation 101, is twice the sq in of passive intake as exhaust. That would be 150ish, or 10x15, 12x13, 2-10" round, etc.
You may want to add some sq in to compensate for the filter resistance. I believe you only need about the same number of sq in of filter as intake. You can go bigger if you want, but I wouldn't go much bigger.
If you want to go with an intake fan, you'll need the same size as exhaust fan, depending on what's between them. Passive should work fine, without the unknowns [to me] of using an intake fan. Less cost too. Good luck. -granger
uraceulose
Member
Thanks again so much you guys. This should be enough to get me going again..
Going to try (2) 10 inch ducts mounted to the window then straight into the tent with filters.
Trying to decide between doing the intake box OR just running the 2 10 inch ducts straight into the tent.
Going to try (2) 10 inch ducts mounted to the window then straight into the tent with filters.
Trying to decide between doing the intake box OR just running the 2 10 inch ducts straight into the tent.
uraceulose
Member
Another quick question...currently I have a 6 inch inline 440 cfm fan and matching carbon filter.
If I just set this vertically on the ground inside the tent 24/7...will it be able to keep up with the amount of air flow going through the tent and still keep the smell to a minimum?
Just wondering if it maybe be smarter to add another 6 inch fan/filter and run both for 880 cfm minus the filters/ducting up into the attic.
It will require roughly 6-8 feet of ducting to vent with 1 90 degree bend to get it to the attic.
Basically, now I'm looking to filter the exhaust for smell and still maintain enough flow.
If I just set this vertically on the ground inside the tent 24/7...will it be able to keep up with the amount of air flow going through the tent and still keep the smell to a minimum?
Just wondering if it maybe be smarter to add another 6 inch fan/filter and run both for 880 cfm minus the filters/ducting up into the attic.
It will require roughly 6-8 feet of ducting to vent with 1 90 degree bend to get it to the attic.
Basically, now I'm looking to filter the exhaust for smell and still maintain enough flow.
