Silent Exhaust Design

Hi guys, just wanted to share an exhaust and air circulation design with everyone. Please feel free to comment, ask questions, or share ideas for improvement...and if you think this setup sucks...tell me why, I can take it, I'm a big boy When the following closet set up was designed, it was known ahead of time that cool tubes were going to be used. However, this system could be easily modified for non air cooled lights and I will explain how.
The main idea with this design was total silence plus smell and heat removal, not maximum air circulation. This was accomplished via other fans in the room. A bonus of this design is that all ballast heat is also removed from the grow room.
Before we get started I want to add one more thing. This design was for a closet that is 216 cubic feet (66"x61"x93"). All exhaust designs, fans, and carbon filters were selected based on this fact as well as the amount and types of lights being used. I know it probably can go for most without being said, but I should still probably mention that you can not simply copy any design without considering the amount of heat you are going to generate and the cubic feet involved. The last thing you want to do is call the fire department to your home at 3am because you started a fire. After this system was designed all lights filters and fans were ran for 24 hours straight to ensure no temperature issues and to also ensure that the exhaust air was staying below 95 degrees (this was necessary here because we are not venting outside the home and because of where we locate the ballasts...I will explain why later).

Ok first thing first..here are our supplies....

1) saw
2) anchor screws
3) caulk
4) insulation (pictured below, this is to reduce noise, NOT to insulate for temp.)
5) 6" cool tubes
6) 25 feet of 4" dryer vent ducting
7) 6" to 4" reducers....I know you probably just read that and have no idea what it means so they are pictured below. These are necessary to connect a 6" diameter cool tube to 4" dryer ducting.
8) 4" and 6" flanges (clamps that connect the ducting)
9) 5 sheets of 1/2 inch fiberboard
10) Exhaust Fan...For this room we selected a Vortex 4" fan rated at 172 cubic feet per minute (pic below)
11) Lastly, your carbon scrubber. The carbon scrubber and fan you select will be predicated on the cubic feet of your grow space. The carbon scrubber we will use here is 12" long and has a 6" diameter with a 4" opening. It is rated proportionally to the vortex fan being used.

next post forthcoming momentarily...





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Time to get to work....

The first thing you have to do is attach your reducers to your cool tubes, this is pictured in the previous post. Once this is done we go ahead and hang the cool tubes so that we know exactly where we want them and how much dryer ducting we are going to need. It is important for maximum air flow that dryer ducting be extended to it's full length.

Once your lights are hung and your reducers in place, we figure out where we want our fan box to be built. In my experience it is the exhaust fan in a setup that will generate the most noise. So we took the ventilation pictured in the previous post and lined a box we built high up on the wall. This box is made with the fiberboard mentioned in the previous post and sealed with caulk.
#1 shows your air intake line.
#2 is the fan in the box on the wall. You can see the cord coming out the side of the box, we cut a hole, run the cord, patch it, and seal it with caulk. The insulation in the sealed box causes the fan to run almost completely silent. You could be asleep under the box and not hear anything.
#3 is your exhaust line coming out of the fan and down into our SECOND box on the wall.
#4 This is where most exhaust designs differ from ours. Instead of running this exhaust line out of the room and through a carbon filter, we run the exhaust into a carbon filter contained in a second box.
#5 In this box we place our ballasts. In this pic you can see two 600 watt HPS ballasts and one 400 watt MH for the mother chamber built in the closet.
#6 This is the exhaust hole for the second box, 4" diameter again.
#7 If you look very closely at the bottom of the photo you can see the top of the 4" dryer vent that we will use as the exhaust hole for the room. This is where the air will be run out of the room. Ideally this would up higher, but for stealth it had to be lower (will explain later).
next post comming......

Here is what the setup looks like once the boxes are sealed up and everything is running.

last post comming in a moment...

I said I would explain why we are not venting outside the home and why the exhaust hole needed to be located lower on the wall.
Well the back of this closet backs up to a spare bedroom with it's own bathroom and a vanity just outside the bathroom.

Here you can see the vanity as it looks normally...

And in the second pic you can see the exhaust hole with everything removed from the vanity area (spare clothes and a bag of clothes for goodwill plus a spaceheater). So the exhaust hole had to be located in a certain spot on the back wall of the closet for stealth.

The other reason this closet was designed to NOT vent outside the home is because the home is in a cold climate and the heat is run in the house 9 months a year. This way we take advantage of the heat generated by the operation. We did notice a problem with humidity in the spare room, but this was easily solved with a dehumidifier.

As stated above we needed our exhaust heat to stay below 95 degrees. This was because we needed to know that the ballasts were operating in a a safe temperature environment in order to prevent overheating, and we also ran one of the 600 watt cords through the exhaust line into the spare bedroom so that it could run on a different electrical circuit.

I also said in the first post that this design could easily be adapted to use with non air cooled lights and it can. Look at the pic in the second post. If the lights in your room are not air cooled and you can not pull air through the lights and into your exhaust fan, you can simply set up your lights, install the exhaust box as high as possible on the wall since hot air rises, and use no hose. So if you look at the pic in post #2, you would simply have a hole in the box at point #1 in the pic instead of dryer line running in. Air from the room would just be pulled in through this opening.

Last tip...Since your second box (the lower box on the wall that holds the ballasts) is going to be pressurized with all the air blowing into it, you need a very good seal around the edges. Check this box regularly to ensure the caulk is holding and that hot air is not leaking back into the room.

Excellent

How long did it take?

eace:

Two weeks of planning and arguing over the design, two days for me and my buddy to build it.

2 weeks of arguing, lol.

Nice set up NYC. I just got my basement sorted out. I'm going to start building next week. Thanks for taking the time to post this. Oh and gl. I live in a colder climate as well, may need to ask you a few questions, when the time comes.

We ran the one cord through the exhaust line only because we knew we would be able to keep the temps at a safe level. You are correct it is not a good idea and I would not recommend doing it unles you are careful with temps and test everything thoroughly.
We also did not want to make any more holes in the wall or the exhaust box than necessary.
Yes the fan box is lined with noise reducing insulation. If you look at the pic in the first post you can see what we used. It has the pic of the Pink Panther on it. If you zoom in on the pic you can read on the package that it is labeled as noise reducing insulation.
The vent louvers are plastic and make no noise, the exhaust air flowing out here is at such a constant level there is no movement to them. We did move the cord so that it was coming out of the bottom of the 3 holes in the exhaust vent and not the middle one enabling the lower louvre to stay open.

NYc - just curious. My tent is a little smaller than your room. I am using the same 4" vortex that you are and a slightly larger carbon canister. Noise has been an issue for me, and right now my stem starts with the can in the tent and exhausts through the fan mounted above the tent, mounted on the wall above. While i can deal with the noise, i am constantly battling odor. Do you find that pushing air through the can does a better job of knocking sown the smell than pulling it through? Was thinking i had to go to a larger fan/can combo to get it under control, but if you are having good luck with this, I may just try to re-arrange my components. Looks like you put alot of thought into this - good job!

scatking said:

NYc - just curious. My tent is a little smaller than your room. I am using the same 4" vortex that you are and a slightly larger carbon canister. Noise has been an issue for me, and right now my stem starts with the can in the tent and exhausts through the fan mounted above the tent, mounted on the wall above. While i can deal with the noise, i am constantly battling odor. Do you find that pushing air through the can does a better job of knocking sown the smell than pulling it through? Was thinking i had to go to a larger fan/can combo to get it under control, but if you are having good luck with this, I may just try to re-arrange my components. Looks like you put alot of thought into this - good job!

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Are you using an intake fan or passive air intake on your tent? My carbon filter is designed for air to be pushed through it, not pulled. I am not sure how effective reversing it would be but I am having zer otrouble with odor. Do you run the exhaust and carbon filter 24/day?

Intake is passive - the tent always shows signs of negative pressure, so I am assuming that the exhausted air is being replaced. I run the fan 24/7. Before i chuck the whole set up, I will give the push a try and see if that does any better. thanks for the great post and good advice.

yea try flipping it and see if that does more for the smell. If the noise is an issue it is really easy to put your exhaust fan in a box lined with that noise reducing insulation, it prevents a LOT of noise. All you need is a 4" circular drill bit to cut vent holes for dryer ducting, and I got my bit for like $8.

could i take a 6" inline fan and hook it up to some ducting (pulling air from the grow box) and put it into a box (such as yours) then simply have a hole in that box to exhaust the heat? or would the hole in the second box give off just as much noice from the fan?

i only say so because idk if my fan is strong enough to push through a carbon filter

@NYC_Diesel x Jack_Herer....If you need to move more air than that and do it super whisper quiet there is an easier and a bit cheaper way too ...Go to any thrift store look for an old hepa filter the size you need rip the filter out since you don't ned that then you can a build it into a box or duct it directed into your hood like I did and NYC cause they run in homes they are whisper quiet and they move allot of air dirt cheap cause they are usually energy star rated for long runs in homes and pulling out the filter it is all air flow so they move tons ...just a thought to save a few bucks

TokeWithHope said:

could i take a 6" inline fan and hook it up to some ducting (pulling air from the grow box) and put it into a box (such as yours) then simply have a hole in that box to exhaust the heat? or would the hole in the second box give off just as much noice from the fan?

i only say so because idk if my fan is strong enough to push through a carbon filter

Click to expand...

Hi Toke,
Is there any way you could figure out the model and model number of your fan so we could figure the cfm rating? If you have an inline fan then it will more than likely work with some size of carbon filter. Even the lower cfm 4" fans are powerful enough for smaller scrubbers. Without a carbon filter all you really need is the one box for the fan to keep it silent. Just vent your hood into the box with the fan, and then exhaust the fan out the box. If you build the fan into a thick enough box with the noise reducing insualtion, it will cut all noise. If you find that you still have noise coming out your vent hole, then you could either make the vent tubing longer between your fan and the exhaust hole so that the noise has to travel further through the tube, or you could buy a noise reducing sock that goes into the end of your exhaust. If you are just having trouble with sound coming from your exhaust hole then this might be easier than building another box. I think I have seen the socks on Ebay, pretty cheap.

Hey mystic, any chance you seen a setup on here like that or seen a sticky on how to do it?

its the 6" fan from htg supply heres the link
hxxp://www.htgsupply.com/viewproduct.asp?productID=46447

Hi Toke,
That is a great fan, I have one just like but I am not currently using it as there is no need. Yes, that fan design is much louder than the other I use. The good news is that it is definitely powerful enough to use with a carbon scrubber. Using a carbon scrubber would really cut most (like 90%+) the noise that your exhaust fan is creating coming out of your vent hole assuming you place the carbon filter at the end of the chain and push air into it. You have a 6" fan rated 160-250cfm, so you could easily use a 4" carbon scrubber rated in the 160-180cfm range. it would really cut the noise AND the smell. You would just need to reduce the 6" to 4" for the scrubber, if you look at pic #2 in post #1, you can see the reducer you need, less than $4 at a home improvement store (and you will need the flanges that clamp down where you connect your pieces to make the seals air tight, these are like $1 each).

I have used three different types of carbon filter and the best I have found so far is made by Foothill Filters. Here is the one that I use in my closet now (yes the one in my pic above is a different color) and would work well with your fan, you can get one for around $65:
just change the xx to tt:
hxxp://cgi.ebay.com/4-X-12-CARBON-AIR-FILTER-HYDROPONIC-ODOR-SCRUBBER-HPS_W0QQitemZ120422750321QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c09c15871&_trksid=p4634.c0.m14.l1262&_trkparms=%7C301%3A1%7C293%3A1%7C294%3A30

This is a link to one being sold on ebay, if it has expired just do a search online for "foothill filters", the one I use is 4x12 and rated for exhaust fans rated at 100-200cfm.

nyc i looked @ foothill also. i found that for roughly same size filter compared to htgs filter, htgs filter has almost twice the carbon. also you can push or pull air through your scrubber, it dont really matter. ive run both ways & see no differance. the poly media wrapped around your filter would be a pre filter to keep dust from plugging up your carbon. anyhow take care.

docfishwrinkle said:

nyc i looked @ foothill also. i found that for roughly same size filter compared to htgs filter, htgs filter has almost twice the carbon. also you can push or pull air through your scrubber, it dont really matter. ive run both ways & see no differance. the poly media wrapped around your filter would be a pre filter to keep dust from plugging up your carbon. anyhow take care.

Click to expand...

Thanks doc, when it coes time to replace it I will check them out. I have noticed zero odor running it both ways, but I have been told that the filter will more than likely not last as long having air pushed into it instead of pulled, do you find this to be the case? I pefer having it this way just becasue if I put the fan behind the filter in the chain the fan noise generated comes out my vent a LOT louder.

thanks alot nyc, i think im going to purchase a filter soon! and thats good because smell was going to be a problem for me! but also do i need the stiff ducting or can i use the flexible dryer ducting to run this system? also can i build a box big enough for the carbon filter and the fan and just have it shoot out the box?