Venting and Grow Room efficiency ( get your Ducts in a row)

ilovefatbud69 said:

hey im just starting to setup a grow in a new place and my space is around 3'x3'x3' and i have a 2 foot fan that seems too close to the plants. If they sway in the current are they gunna be jepordized?

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If it isn't breaking branches it should make them stronger...

Hey subcool I was just wondering wouldn't pushing the intake into the room through the hoods force the hot air from the light into the room? I thought the idea of the glass hoods was to exhaust the built up heat within.

Ganja Geek said:

If it isn't breaking branches it should make them stronger...

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not totally true.. there is such thing as wind burn, and if its too dry and too windy you'll cause transpiration (plant sweat) to go to fast and close stoma's and weaken leaves.. to much wind can certainly be a problem, even before branch breaking.

Ganja Geek said:

Hey subcool I was just wondering wouldn't pushing the intake into the room through the hoods force the hot air from the light into the room? I thought the idea of the glass hoods was to exhaust the built up heat within.

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I'm not subcool and I don't play one on the internet BUT I believe fans work best pulling not pushing, but the HVAC guru would know for sure.

Yes you dont push air its not efficient in venting kitchens bathrooms laundry etc you pull the air its the proper design according to ASHREA

Sub

Thanks for clearing that up you guys.

Hey subcool,
thanks for all the great info. I have been stumped for weeks on what to do about my ventilation situation. About six posts back Jack45 mentions a situation similar to mine, but no one really answered his question besides blakbotany mentioning something about CEA (which i will have to look up). I have a small 6x2x7 closet that has double doors that i could leave open. The closet is inside an approximately 15 x 18 foot room with a single window and door. The window is right in the front of the house in plain view. Can I effectively cool the closet (single 400 watt HPS/MH) by leaving the doors open and circulating air out of the closet and around the room (this is what i prefer to do-it seems easy and inexpensive)? I can also open that room door to supply fresh air as needed, since stealth might only be essential when i have an occasional guest. It is very hot outside the house and can be quite cold in winter. I could cut holes in the roof of the closet for intake and exhaust from the attic above, but that air is really hot already and I'm concerned with mold. I've thought out these scenarios, but I'm just not sure what to do. Could you please advise me?

Also, this room has 2 central ac/heat vents. I'm not sure if they both blow cold air, or just one and the other maybe returns. You can tell I know a bunch about HVAC stuff. Thanks in advance.

sub- for a new guy like me you have any links/threads that can show me a simple ventilation system setup with with proper ducting and fans? ive spent the past couple days on the super soil thread and cant get enough and wanted to get a little me in depth on ventilation. im living in michigan and will be using a basement setup and since winter is upon us in a few short months i dont see temps being too much of a problem. I just wanted to get a better visual on how a simple 1 1000watt hooded system could be built cost effective. thanks in advance

I have a 5' x 6' x 8' high room. I have a 6'' can fan venting a 1000W air cooled hood with glass. I can not get the mother fucker under 86 degrees. I live in the desert so today its like 110 degrees so a intake hole is not gonna cut it. I brought AC duct into the closet from the room not being used. I am venting into my attic and now I am tthinking I should just vent into the room so I am not sucking up all that cool air and killing my AC bill. I got the temps as slow as 86 but thats with the fan running non stop.

hey there Sub,

I appreciate the hvac help you offer, and i'm hoping to get some feedback on a stealth closet i'm designing. I ordered a 530 cfm inline fan from Tjernlund, which I'm hoping can cover all exhaust:

- veg room: 7 ft3
- flower room: 13.75 ft3 (want to concentrate more suction to this room)
- passive intakes
- cool tube for 150w hps - using 4" ducting (will need 6to4 reducer)

Below are is my idea. I'm planning on using rigid ducting as much as possible, and flex as little as possible. I'm also wanting to exhaust to a little box with a passive outtake, where i'll also put a little ona gel can.
I have a bunch of little cpu fans that I could also use, if needed. Temps in my room range from 70-80 on average, but will get up to 85 at times. (I am strictly anti-AC). I'm thinking of making some kind of dampers to the veg room, as it will not need as much exhaust.

I hope this is all the info you need. thanks!

subcool said:

Yeah I am third generation HVAC good call

Sub

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Sub...I run a mini split system (29,000 btu, non DC inverter type, 13 seer, no heat pump). From your HVAC experience would a DC Inverter type mini split control the temp swings I get from my current mini split?

Currently when system enters defrost mode, temps climb. I use a large inline fan with air baffle and temp controller to kick in if temps ever rise to unacceptable levels while defrost mode is activated. Any thoughts?

Man as much as I saw I guess thats technology that I never saw to be honest. Inverters and such were just coming out in the 15 seer Tranes when I was already in sales.
I dont understand why your defrosting though your using the split in the cooling mode to lower temps correct?
Defrost is in the heat mode using hot gas to defrost the ice from the outdoor unit so I am confused here.

Sub

subcool said:

Man as much as I saw I guess thats technology that I never saw to be honest. Inverters and such were just coming out in the 15 seer Tranes when I was already in sales.
I dont understand why your defrosting though your using the split in the cooling mode to lower temps correct?
Defrost is in the heat mode using hot gas to defrost the ice from the outdoor unit so I am confused here.

Sub

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That correct, in cooling mode. According to manual, the light that flashes while system is no longer cooling is defrost feature. I figured the indoor system was freezing but again. I'm not an HVAC guy.
I'm suspecting I miss calculated my true heat load and the system is getting temp down too fast.

Yes its sounds like its short cycling due to low pressure ( low temp at evaporator)
Do you know the refrigerant charge is correct?

Sub

Yes, I had a reputable HVAC friend vacuum pump and check/add refrigerant after installation. Works like a champ. Unfortunately, my friends hasn't been able to make it out to inspect, leaving me to seeks answers else where.

Short cycle seems like the culprit. Would a added dose of heat help solve the issue? I could re-route ballest/control room exhaust directly to flower room fairly easily.

~HD

Hey Sub! Which of your TGA strains has the easiest smell to disguise? (doesn't stink too much

I'm just in veg now and don't have my 400w hps rolling, but I'm pretty worried about heat/vent when it gets up. I'm growing in a closet, there's no way to vent air in or out. The closet all together is roughly 10x6. My plan is to vent the flower tent out into the rest of the closet and through an odor scrubber with an air cooled hood. Is there anything I can do about the heat in the closet, though?

Sub,

I was wondeing if I could get you to critique me on my grow setup. Pros/Cons what I should change and what I shouldn't. The following link is pretty much the exact same setup I am using for my grow. http://www.youtube.com/watch?v=WVqu4oz2EbM Keep in mind that I am setup in my basement (Approximately 800 SqFt Unfinished) and my exhaust is being pushed directly into my basement as I am at a loss on how to vent to an outside source. My wife will not let me cut, drill or make holes in anything. I do have windows down there that I could possibly vent to, however I am not sure how to go about doing so without leaking cold air into my basement. I'm mainly concerned about this during winter months which we are fast approaching. It get's cold in the mountains during the winter.

Thanks in advance!

I am having problems with my flex ducting sweating very bad. Its coming in through my veg room and into the bud room, were it hooks up to the lights. I am using t-5's in veg, so the air in the ducts is cold and humid and the air in veg is 80 degrees. No problems once it hits the hoods. Big problem. what do I do?

the moister doesn't sweat through the duct work. the duct work is cold and the hot air in the room condences around the ducting, meaning, that moisture is coming from inside the room.. just a heads up on what is happening