heat help

[x Big Dave x]

'sup ppl

Just a plea for help in getting my temps down a touch. Running a 600w (24/7) in a 4x4x6, big enough exhaust fan 'n 125cfm intake from outside.
Temps are between 28-30c (82-86f). I've got a clip on (non osc) 5" fan in there but it's pretty weak. As it's getting colder im hoping the temps will come down a bit in time anyway.

Just wondering if adding a 9" osc fan would help bring the temps down a touch? Im not too sure the exhaust is doing it's job too well, does it matter that it's got about 3 foot of ducting between the filter and fan?

Thanks for any help or advice

 

[Dr. Manny Bowles]

How many cfm's is your exhaust? Where are you exhausting to?
Adding another oscillating fan isn't going to bring down the overall tempurature of your room, you need to remove the warm air and replace it with cooler fresh air. 3 feet of ducting shouldn't be slowing down your fan much, can you elaborate on your setup a bit?

 

[pcduck]

I do not think a 125cfm fan has enough pull for a filter and to clear a room 3-4 times a minute...Is this an inline fan or a duct booster fan?

 

[Krazeydays]

82-86 don't sound to bad for that space IMO. but a 9" fan would help break up some of that heat. what size is your exhaust fan?

 

[x Big Dave x]

Thanks everyone.. The exhaust is a 5" inline 250cfm and is rated for the size filter i've got.. Silly question but putting my hand on the filter should I be feeling any hint of suction? Oh and it vents out to the room but the room is a fair size and has a window open slightly all the time. Im trying to work on keeping that room a bit cooler but it's a bit tricky. My plants are looking pretty healthy but I can't help but think the 2 50/50's didn't make it due to the heat. If I can just knock of a few degrees!

Cheers ppl.

 

[leafminer]

Ducting REALLY saps a fan's ability to move air. Hmmm . . . I cannot recall anyone here ever doing a little DIY flow meter, I think I will investigate.

 

[x Big Dave x]

Ducting REALLY saps a fan's ability to move air. Hmmm . . . I cannot recall anyone here ever doing a little DIY flow meter, I think I will investigate.

Cheers leafminer, I thought I read that somewhere way back in the day. I tried telling my mate! It's a bit tricky hanging the fan in there with the light 'n all but I might have to give it a try.

 

[Dr. Manny Bowles]

I would think with a 250cfm fan you should be able to feel air moving if you put your hand next to your carbon filter, especially with only 3 feet of ducting. By venting back into the same room you are really only recycling the air and bringing in bits of fresh air here and there thru the window. If you are unable to vent your exhaust somewhere else like your attic or crawlspace, or even a different room in your house, you will need to somehow bring in more air from the window. And this is kind of a temporary fix IMO. Good venting is essential in any growroom. Is this a window other people/houses can see?

 

[x Big Dave x]

Sorry meant to say, the 125cfm intake is air coming from the chimney breast (im tapped straight into it via a foot of ducting!) this air is pretty cool so thats why im a bit confused over my temp probs.

And yeah, the window can't be opened too much or from certain angles the ducting shows.

As for the filter, i can barely feel anything (maybe a slight airy coolness) with my hand just touching it.

 

[nouvellechef]

If your air coming in is over 80. Won't matter if you have a 1200cfm intake. Pick up a small AC.

 

[x Big Dave x]

If your air coming in is over 80. Won't matter if you have a 1200cfm intake. Pick up a small AC.

Cheers but the intake's air is a bit cooler than that.

 

[dirtyolsouth]

Hi,

Have you considered picking up an air cooled hood? There are a few options that would really help your temps that I can think of. Your best solution may require investing in a more robust exhaust fan along with an air cooled hood or a cool tube light fixture design. There a few ways you could approach your setup, depending on your room. Your current 200 cfm fan is adequate for moving enough air through your filter to properly scrub the odor and you can use it hooked up directly to your filter to constantly exchange and cycle the air all within your grow room. The fan on the filter will pull air from within the room and blow the odor free scrubbed air back into the room and keep it from building up..

If you get an air cooled hood or a cool tube you can hook up ventilatation a couple of different ways. You can hook it up as an "Open" ventilation design by leaving the intake side of the hood or cool tube open to pull air from within your room and thru the hood/tube and then you'll exhaust the hot air outside of your grow room. For a 600w HPS it's going to take closer to a 400+ cfm inline fan an an air cooled hood to move enuf air to cool thing down significantly. Another option is to hook up your carbon filter on the front end of your open exhaust system by attaching the filter to the intake side of an air cooled hood/cool tube. But this will probably require an even stronger 6" inline fan closer to 600+ cfm.

And yet another option is to hook up your ventilation as a 'closed' ventilation system... You would need another intake hole and you would feed duct from that intake hole to the intake side of an air cooled hood/cool tube and use your fan to pull the air through your light and route the exhaust out of i.e. a hole in the ceiling, etc. What's nice about a closed system is you're not constantly pulling warm air out of your grow room in the winter and cool air conditioned air in the summer. You would still need a fresh air intake though and if you ran your system "Open" you could leave it passive. If you run it "Closed" you'll need a fan to pull cool air into your grow room or an a/c unit in fan mode etc...

Happy Growing!

 

[x Big Dave x]

dude your a legend, thanks for all the options. Just to point out noise is an issue so i've still gotta work on getting the 6" 430cfm inline more quiet before it goes in to operation for the other room. I see what your saying about the cooled hood but im kinda done for money at the mo plus im no expert with DIY and never set up one of those before, for now i'm trying to keep it a bit simple (plus for some reason cool hoods are hard to get over here) and I don't fancy cool tubes much, hot spots and dodgy light coverage 'n all that.

I've got a few things to work with, for a start i'll work on getting the fan hooked up directly to the filter for slightly better suction. I'll get a bigger fan cos I was going to anyway! And hope winter brings in some even chillier weather! I know it sounds lazy but i'd rather live with the higher temps than do major re-jigging, this is mainly due to the location as I don't like to be in there for too long.

 

[legalize_freedom]

interesting post as I have the same sized grow, and I am going through the same thing at the moment... I justhad a 200 cfm take a crap on me, and now after reading DOS post, I'm wondering if it was not a high enough cfm for my application.
I just talked to the guys at the hydro store, about getting a new fan and they told me that 200cfm was enough to pull through my carbon filter, a/c hood and out of the room. I asked about a squirrel cage fan, and they told me it would not matter if I had 500 cfm with that type of fan, that the motor is not designed to be able to pull that hard to go through the carbon filter. They said if I got 170 to 200 cfm CENTRIFIGUL fan, that the motor on that is designed for the type of "pull" I need to go through everything. I'm going to be p.o.'d if I get it home, and set it up, and it doesn't do what it's supposed to do! DOS I trust your experience...so are you saying 170-200 cfm won't pull the heat out of my room in a closed set-up? carbon filter mounted inside grow to wall, ducting through a/c reflector, and out the side...cause I'm about to go drop 120 bucks..lol I want it to work!

 

[dirtyolsouth]

interesting post as I have the same sized grow, and I am going through the same thing at the moment... I justhad a 200 cfm take a crap on me, and now after reading DOS post, I'm wondering if it was not a high enough cfm for my application.
I just talked to the guys at the hydro store, about getting a new fan and they told me that 200cfm was enough to pull through my carbon filter, a/c hood and out of the room. I asked about a squirrel cage fan, and they told me it would not matter if I had 500 cfm with that type of fan, that the motor is not designed to be able to pull that hard to go through the carbon filter. They said if I got 170 to 200 cfm CENTRIFIGUL fan, that the motor on that is designed for the type of "pull" I need to go through everything. I'm going to be p.o.'d if I get it home, and set it up, and it doesn't do what it's supposed to do! DOS I trust your experience...so are you saying 170-200 cfm won't pull the heat out of my room in a closed set-up? carbon filter mounted inside grow to wall, ducting through a/c reflector, and out the side...cause I'm about to go drop 120 bucks..lol I want it to work!

Hi bud,

Ime they are right about the squirrel cage fan not having the pull that a centrifugal fan does for pulling air in a static pressure situation. But, I still think that by the time air is pulled thru your filter, then your hood and pushed out of your grow room that's a lot to ask of a 200cfm fan. I'd much rather approach the problem with overkill. My bloom space is challenging to say the least. I use a 1K HPS and also a 6 tube 4' T5 fixture for a side fill light in a 2 x 4 x 8 closet. I have a 30lb carbon filter first in my ventilation chain... I use a 6", 630cfm Eclipse fan to pull air first thru the filter then thru my cool tube that is inside a standard style reflector hood and then thru about 6 feet of duct to my fan that is up in my attic. In the summer I use a window a/c unit and have to run the fan at 100% to keep temps in the mid to upper 70s. From fall until spring it doesn't take near as much air movement to keep temps down so I use a Speedster Motor Speed Controller ($29) that I vary the fan speed with and it gives me precise control over my grow room temps and fan noise. I run my lights from 8pm til 8am so I during their 'lights out' during the day I can back down my fan to around 40% which makes the ventilation much more stealth, just enough to keep negative pressure maintained and all airflow going toward the closet and thru the filter into the attic. Having laid all that out for you I think you would do much better to get a more powerful fan. A 6" 630cfm runs around $180 and that may be more than you're looking for but with that and a Speedster you'll have much more control over your situation and you'll be able to readily adapt easier as seasons change. Look around online too and if you're in a med mj state Craigslist may be a great place to look for bargain gear.

Peace!

 

[zem]

have a couple of oscilating fans that i threw out of my grow for good, they dont help lowering temps and can create a windy room perventing good exhaust disrupting the air current in the room they can cause a rise in temp and their motors also give heat so you'll be adding wind thats only meneficial in preventing surface layer mold but no good to prevent big bud mold from the inside of buds so gettin AC with its compressor unit outside will be best if not you'll need a dehumidifier but this gives out heat and noise... cheers

 

[nouvellechef]

Zem, whatever strain you smoke. I want some. You give out the worse info I have seen on this site.

 

[zem]

Zem, whatever strain you smoke. I want some. You give out the worse info I have seen on this site.

pfff what now? what do you disagree with me on in my post? i tried oscilating fans if the room is huge it will be needed to move air around but in small grow chambers it's really no good and did you ever hear the noise and heat the dehumidifier gives out?

 

[legalize_freedom]

I'm telling you...I've been trying real hard to be patient...but the guy keeps giving bad info...my god! you need to move air around in your grow, stagnant air causes stomato to close. a fan on young plants helps to strengthen stems, keeps bugs down, and keeps mold from setting into buds...Zen go back to your romp a room grow guide...this is serious here...stop giving out WRONG advice!

DOS thank you for taking the time man...much appriciated!

 

[zem]

a fan on young plants helps to strengthen stems, keeps bugs down, and keeps mold from setting into buds...

this explains a lot about your grow, you grow in pest infested room if you need a fan to keep them off then there are lots around your res is full of larvae eek! and your buds are not big enough to need a dehumidifier. if your buds are big enough i tell ya you can have a windstorm of oscilating fans and still get mold in the inner part of the bud you need to get RH down. go ask what RH is now