Need help cooling down 4x4 tent

I’m setting up for my second harvest ever. I upgraded my tent to a 4x4 Gorilla Shorty with extension. I cant get my temps less than 84 with the lights on. My temps before were 77-78 in a 2x4 with single 300 Rspec. Same fans and location.

Room: Closet 5x10ish Ambient starting 73F
Tent: Gorilla 4x4 Shorty with extension
Lights: Two 200 HLG 300 Rspec & one UVA bar.
Intake Fan: AC Infinity Raxial S6. Normally pulls from floor next to tent. Moved intake to next room which was also 73F. Didn’t help.
Exhaust Fan: AC Infinity T6 with carbon filter. Approx. 25 feet of ducting to window
Circulation Fans: Lasko 42in Tower Fan. Two 6 inch desk fans.

Tent temps reach 84-86 at full power. Ambient room in closet climbs to 75. Just having the doors open for these pics, the tent temp dropped to 80 within 1 minute. Would an 8 inch exhaust fan fix this or do I need a portable air conditioner? The house AC really doesnt reach this area well but temps are typically 71-73 in the closet with the lights off. In the past, I’ve tried an oscillating fan moving air out of the closet but it doesnt seem to help at these higher temps. These temps are stable regardless of time of day.

Any assistance or suggestions are greatly appreciated!

More airflow is always better, but the best thing you can probably do is mount your light ballasts/drivers outside of the tent.

Give me a few minutes and I’ll post a pic of how I have my drivers outside of the tent.


Seems to be a problem with uploading pics to the site. Will try again later.

If you can use a Window AC, it will cool down the tent. Because it will help control the room temp and this leads to the tent temps coming down.

I am cooling the room down as I type this.

You can see the temp in the tent rising. Its dropping because the room is cooling down. I hope this makes sense.

If I had to guess, too much ducting to have with filter for that size fan. The static load will greatly reduce amount of airflow.

Even with larger fan you will have to expect your tent temps to be warmer than incoming air. If you are experiencing ambient temps of 73-75f, than I wouldn’t expect your tent to be much less than 83-85f, which is upper limit of where you want to run.


That’s what my quick experiments are showing. The exhaust fan is struggling. I’ll start with trying a small portable air conditioner as that seems to be the bigger issue to stabilize. I can’t really do anything about the long ducting run other than have a contractor install a vent. Looks like the 8 inch is rated high enough with the restrictions it will have. I needed a second fan to make a drying tent anyway.

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You can get an inline booster fan to help move the air over the long distance. If your previous tent was of a poorer quality then your gorilla that could explain the extra heat retention. Your old tent just wasn’t very efficient by comparison to the new. Sometimes an upgraded piece of equipment will expose other pieces of equipment that also require upgrade to function properly with your initial upgrade.

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Maybe instead of 150 on a portable tty a raxial 6 inch as a booster with the exhaust to help get the flow going better. 26 bucks vs 150 its ur call tho. If 84 is the most it gets i hear thats not really horrible as i alway thought it was too. I try to stay between 75 and 78 if possible but lately its been up there in temp


I’m going through the same issues, Sour Tangie isn’t liking it to well either. Temp 78-82.
Blackjack, Super lemon Mac just flowering and getting dense buds, looking good. Smelling great.
4x4x8 Vivosun tent,
MAXSISUN 400W Grow Light, Remote Control Dimmable PB 4000 Pro LED
Vivosun 6”390 cfm inline fan, w/controller
6” fan, 10” fan, just replaced the 4” inline fan stopped working.


Damn sexy looking 4x4 I can’t wait to get some space and get the tall one , shorty you gonna need some power to cool that since it’s such a compact space , infinity 6 inch and some flip fans


The temps were only 2 degrees cooler with my 6 inch Raxial booster inline with the exhaust. It seems the big weakness here is the room temperature. I’ll pickup a portable air conditioner tomorrow.

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I’m liking it so far. Just have to solve this heat issue. I wanted the full-size but the height of my closet prevented it. This shorty is squeezed in there. Haha!

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I’ve seen these used before between two tents. Has anyone connected a tent and portable air conditioner to the same exhaust duct? I was thinking keeping the existing 6 inch T6 but connect it about 10 feet down with the air conditioning using this Y-duct. I’m guessing the output duct should be a little larger with the booster in-line with that? Just thinking of ways to keep the installation clean.

If u keep the lung room at a good 70 or so the tent should only be about 5 degree higher. Or are u talking on just venting tge acand tent out the same tube ?? Hmmm. Im watching to see the answers on this one too.

I was talking about venting the AC and tent out the same duct. After doing some reading, there may be some pressure issues between the AC and tent. I think it will be easier just to run separate ducts. Either way, I’m open for suggestions as I’m just using Google for my research.

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It might be the area but I’m in a metal shed :metal:t4: so my plants just have to deal with it

I see you answered your own question in the statement that said the temp dropped to 80 in under a minute when the door was opened. Which would mean there is insufficient intake to the area.
When exhausting out of a room you need sufficient intake to the room for it to get the airflow needed to make a difference.

Great topic and as always thanks for all the great info. I have the same issue. Just moving from a single tent to two and added a California Lightworks 1100 for the Flower Tent. 4x4 Gorilla. Just like the original but upgraded from their 550 light. This has already given me some tips on how I can clean up the air flow that will help I suspect. Does anyone have any experience with these? I am dialing them down which will help solve the other half of the issue I hope but would love feedback on anyone who has already crossed the bridge. I can keep them around 78-81 or so with the room at 69 but that number still makes me nervous. If I am overthinking that it would be great to know by the way, and yes. I know. Its too much light for the tent and way more than I needed to spend. But I love the 550 and fooling with the controller, so I was hooked. :slight_smile:

You mention the house AC doesn’t really reach that area (ambiently, I assume), but is there a vent anywhere around that you could run a hose from and pop it into your tent? Similar to this pic but yours would be longer I imagine…

It won’t PUMP air into the tent, but it will certainly push a little in & your other ventilation should help pull it through as well. Dropped my temps 5 degrees instantly from 84 to 79, but my run is very short, so… anyway, hope it helps!

@Plutarch I don’t have any experience with those lights but that temp range is ok. I’m shooting for 78-80 stable.

@WyvernWeed I like the idea! There is a register above the door to the closet. Unfortunately, the air flow there is almost zero. It wouldn’t be worth running a duct from it.

Rather than keep putting bandaids on the problem, I decided to just fix it right. I installed a portable air conditioner and it is working great! I also upgraded the fan/filter combo to an 8 inch from AC Infinity. The long duct and bends were pushing the 6 inch exhaust a bit too hard. Using an in-line booster with the 6 inch (which I already had) helped but just complicated the setup.

Tested for a day. Air conditioner set to 72. Lights maxes out. Tent temp held at 78. I just need to clean the tent and I’ll be ready for my next grow. I ran a test where I removed the air filter from the fan but left it inside the tent. There were tiny fibers (I’m guessing from the filter itself) which my circulation fans were more than happy to spread all over. I wouldn’t even have noticed if it weren’t for the UV light being on. Has anyone seen anything like that before? I’ll see if they show up on camera this afternoon.

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