1.5' x 2' x 3' - which exhaust fan?

[sub]

I know a lot of info is out there already, but I think I'm a tad confused with how much CFM I will need.
My box is 1.5' x 2' x 3' and the max wattage I will be using is 350 (if that) while the lowest at 200. With these numbers, I calculate that I should use at least 100CFM to 150CFM (which should be more than enough).
My confusion lies with other people's boxes. I see people with boxes twice as large as mine only using a 100CFM S&P inline fan.

I would love to get the 4" TD-100X which is rated for 135CFM (100CFM on low). - 135CFM is probably the ideal airflow for a box my size, at least I thought. Now I'm jsut confused after seeing other people with way less CFM than I thought I needed.

So for a 1.5' x 2' x 3' box with ~300w usage, is ~135CFM good?
If I did get this, I would plan on using a carbon scrubber, too... would the TD-100X be too weak with a scrubber? Or will it still be more than enough?

I thought I had this all down pat, but I guess I was wrong!
Thanks guys

EDIT: I've decided I will most likely get the Soler & Palau TD-125, which has ~150/200CFM (low/high) and run it on the low setting (hopefully if temps permit)

 

[sub]

P.S. I'm aiming to have just one exhaust fan, but a couple PC fans inside for the lights/flow

Do you guys think that for such a small box that getting one of these inlines is overkill? Maybe I should just use the 3 PC Fans I already have.
Maybe 2x 80CFM 120mm PC fans running at ~90% power (dimmer switch)?
At 12v they are ~30dBA, and I'd love for them to be less. I don't want to spend the money, but if it's worth it I will get the S&P TD-100x or maybe the next one up?

 

[infinitylimit]

You will need to supply what type of light you are using HID, CFL, LED. Each put out different temperatures for different wattages, 200w of CFL puts out alot less heat then HID equivalent.

I use the rule of wattage = CFM, but I also use a speed controller ($10-$20) and dial in the ventilation. You also need to factor in if you use a scrubber which reduces CFM thus I say larger fan with a dial is the way to go.

 

[sub]

I will be using 8 26w CFLs for veg and a 150w HPS + [not sure yet.. maybe 100-200w] CFLs for Flower

 

[DiscoBiscuit]

I use a 95 cfm hydrofarm blower for a 150hps and <100 watts cfl in veg. It's got a honkin' filter and a speed controller and runs much quieter than the rated 29db @ full speed with no filter. You'll probably need more air.

ebay has the 180 cfm model for ~$75 shipped. s&p inline and panasonic whisper models are available between 150 and 200 cfm. IMO, you won't get the airflow necessary with a couple of pc fans. Server fans maybe but they're pretty loud.

If I had it to do over again, I'd consider a panasonic whisper fan. Tough to find anything as quiet.

 

[sub]

yeah.. I thought about the Whisper, and am seriously considering one of the S&P's.. especially with such a small box. Do you think the S&P TD-100X would be sufficient for the exhaust? With a scrubber on it? I can use the PC fans for cooling the lights/circulation

edit: perhaps the TD 125 would be better.. even on the low setting? Might be quieter?

 

[sub]

Yeah I may have to get the Soler & Palau TD-125, 197/149CFM. Under $100, just barely. Not too bad for someone in need of silence and high air flow
I could probably get away with using it on the low setting for ~150CFM
Using this for exhaust and 3 120mm 80CFM pc fans for light cooling/circulation (but probably at 50-75% dimmer) - that should be sufficient for my ventilation needs, right? I suppose if I had to I could use it on the high setting for ~200CFM. Would it be stupid to use a speed controller on it to go somewhere between high and low?

can anyone who owns one attest to the low noise level of high and low on this bad boy?

 

[DiscoBiscuit]

Even if you don't get an answer about S&P noise, you've prolly got the quietest option next to a panasonic. I forgot panasonics are so big. I'd hold off on a speed controller, see if the switch helps first. If low is too hot and high is too loud, a speed controller might help.

That's a lot of light for a 3 sq foot box. I'd consider dual switching with that much light. Eight 26w CFLs would be more than enough to veg and you'd probably have trouble cooling all 9 lamps in 9 cubic feet.

A fan and filter will reduce your grow space if mounted inside. I'd consider mounting the fan on the back of the cab and push through the filter. Your scrubber will double as a muffler.

Check out KolorBlind's mini fridge pics to get a visual of what I'm suggesting.

 

[sub]

Yeah, I'm hoping I can cool the lights well enough. I just built these fixtures:

And yesterday I actually shrunk them down to a square (it's like 9"x9") and the lights are on each corner. But I plan on mounting a 120mm PC fan to the center of the PVC frames with 4 springs (clip the springs from the fan corner to the inside PVC corners) - I'm hoping this would be enough, the PC fans I have are about 80CFM.
And yeah, Thinking now I MIGHT put the S&P outside the box, but I'm also trying to go for stealth, but I may be able to encase it in some kind of matching box or something. I'll have to play around with it.

Also, I don't plan on running all 8 CFLs WITH the 150w HPS, if that's what you were alluding to? I will have some CFLs on during flower with the HPS, but definitely not all 8 26's. Maybe 4 26's, but we'll see.

I'll post a pic of the updated light fixtures tonight, possibly with the fans mounted. Hopefully this weekend I can start building the box and check temps and stuff

edit: P.S. what do you mean by dual switching? Does that mean using ___ lights for veg and ___ for flower? If so, that's what I'm doing. 8 26w CFL for Veg. 150w HPS + X CFLs (still unsure) for Flower

 

[FreezerBoy]

I run a TD 100x with a 250CMH in my garage. OK with winter temps, it's rather useless in summer temps. An S&P will NOT suck like a Vortex(or scream like one). Consider at least one model up from your needs.

 

[sub]

I run a TD 100x with a 250CMH in my garage. OK with winter temps, it's rather useless in summer temps. An S&P will NOT suck like a Vortex(or scream like one). Consider at least one model up from your needs.

Yeah I think I may go with the TD-250, perhaps on low setting if I can get away with it

 

[DiscoBiscuit]

Yeah, I'm hoping I can cool the lights well enough. I just built these fixtures:

And yesterday I actually shrunk them down to a square (it's like 9"x9") and the lights are on each corner. But I plan on mounting a 120mm PC fan to the center of the PVC frames with 4 springs (clip the springs from the fan corner to the inside PVC corners) - I'm hoping this would be enough, the PC fans I have are about 80CFM.
And yeah, Thinking now I MIGHT put the S&P outside the box, but I'm also trying to go for stealth, but I may be able to encase it in some kind of matching box or something. I'll have to play around with it.

Also, I don't plan on running all 8 CFLs WITH the 150w HPS, if that's what you were alluding to? I will have some CFLs on during flower with the HPS, but definitely not all 8 26's. Maybe 4 26's, but we'll see.

I'll post a pic of the updated light fixtures tonight, possibly with the fans mounted. Hopefully this weekend I can start building the box and check temps and stuff

edit: P.S. what do you mean by dual switching? Does that mean using ___ lights for veg and ___ for flower? If so, that's what I'm doing. 8 26w CFL for Veg. 150w HPS + X CFLs (still unsure) for Flower

Forget the switch bs I mentioned earlier. Probably just as easy to unscrew a bulb if necessary. Looks like good work, pics are good too. Wouldn't mind seeing more if you're willing and best wishes with the project.

BTW, it's impossible to guarantee you've erred on the upside. But given enough intake, you should get the benefit of at least several cfls in addition to the hps.

 

[sub]

Thanks! I actually updated / upgraded the lighting fixtures and am looking for some feedback in a new thread here. The fixtures are smaller and they have a fan mounted (with springs!). Have new pics, too

 

[B. Self Reliant]

I've found small spaces to be rather needy in terms of circulation relative to other more spacious areas. After setting up many different grow spaces over the past few years, I've found a 4" Vortex (or equivalent) fan to be the minimum that I'll use. If I can't use a fan that size, then I won't grow the space. Messing around with smaller fans is a PITA and I've found it easier to vent with something a little large than with something a little small.

 

[infinitylimit]

When I try anything other than what BSR is saying I end up with mediocre results. Passive intakes and a larger than needed fan dialed in is the way to go for best results. Ideally ambient a/c controlled. (small grow areas)

Trying anything else will net results but generally require more effort and time than it was worth. On the same level without a goal and tracking results your just shooting in the dark anyway. Keep a journal and let us know what your results are.

 

[B. Self Reliant]

With such a small box, I'm assuming you're planning on the fans being outside the box. If that's the case you have lots of options in terms of silencing a larger fan. You can set an inline fan such as a vortex on top, with the inlet side sealed around a 4" hole you cut in the top of the box. Then just put a rubbermaid bin no bottom & a false back on it so the air has somewhere to go. It will just look like a bin on top of your box. At that point you can even insulate the bin with something fireproof so it isn't so loud.

Maybe that particular idea is a no-go for your specific scenario, but there's almost always a way to use an adequate fan, even with a micro grow.

 

[sub]

Yeah, I've actually been thinking more about this and I have ultimately decided upon getting the S&P TD-125. That way I can run it (hopefully) on the low setting for ~150CFM and even have it for when I start a slightly larger grow (High is ~200CFM). There is an upper compartment shelf in my box that I am going to cut a hole in and hang the HPS through. I can put the S&P up there with the HPS light fixture, along with a carbon scrubber on the other side (using insulated ducting) - it should be just enough room.
So far, my design would go:
upper shelf holding the S&P TD-125, Carbon Scrubber, HPS and power strip
Veg CFL light fixtures will hang where the HPS would go during flower. Additional side CFLs at the bottom/sides, still need to design fixtures (may just make a vertical PVC pole with the lights mounted, nice and simple)
3rd pc fan near bottom, pointing at the plant.

Still debating on combo of sound proof foam and insulation (probably just go with 1/2" insulation sheets), will be lined with mylar

It all looks good on paper, but we'll see how everything goes when I finally get into constructing the box itself, which should hopefully be this weekend. However, I think I am getting sick, so hopefully it passes quick and I can get back to work

 

[qbert]

I think the S&P-TD125 should be good for the space you mentioned, plenty even. You should know that while it's not loud, it's not exactly quiet either. They can be made nearly inaudible by putting them in a little insulated box too. Last thing I'll say is that, at least with these S&P's, you get substantially more airflow pulling through a filter over pushing through a filter.