Tent temp getting too high

Hello, this is my first grow and im coming across heat problems in the tent.
The past 3 days ive had the lights do their cycles so I can gauge what the tent temps would be like.
Well today was a the hottest day past couple days and the temp was really up there.
So, I switched the light cycle to be on at night and off during the day to combat the heat.
I have an inline 6in fan as an exhaust with a carbon filter, and 2 4 in fans for intakes
I have a portable AC in there maxed out to 60, with the exhaust ducted to the outside of the tent
but my tent temp are still 88F with lights off during the day.
Im really worried this is going to ruin my plants or, at least, effect them in a really negative way.
What else can I do to combat this?
Ive spent a lot of money on current equipment, so spending a lot more isn’t that too viable of an option for at least the next 2 weeks and my seeds are starting to germinate now.

@Bobbydigital you’ve been very informative so far, do you think you can help me out with some more here lol

Absolutely! Tell me more about your grow space. Are you in a tent, if so, what size? Is this tent in a larger room? Trying to understand how you’re getting to 88* with an ac at lights off


Im in a 8x4 tent, the ac is 10,200 BTU.
It in a room about 10x10 I believe.
The room itself is pretty warm because of the AC exhaust, but the intakes are on the other side, which that side of the room is a bit cooler because its not by the exhaust.

I would pull the ac out of the tent and cool the outer room (lung room). Your intake fans will constantly be pulling in the cool air. Hopefully there’s a window or another way to exhaust. 10,000 btu can cool 450sqft so you should have no problem cooling a 10x10.

Is the ac off during lights out? Still trying to figure out how you’re getting to 88 at lights off. What’s the temps at lights on?

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I actually tried that yesterday, and the tent temps were 88-90F, but with the ac inside, the temps came down to 82-84F.
I leave the ac on during lights out, the 88F read today was from lights out, daytime, with ac on. The temps with the lights on today rose up to 95F
It might have been it just being a hotter day today than the past couple days, because during daytime, with lights on, I was able to achieve 84F during the day yesterday.
But summer is barely starting here in California, its going to get hotter.

Curious as to how you’re getting 84* (which is good) with lights on but 88* at lights off

Edit: I don’t think I’m understanding. So lights on, at night, you’re hitting 95? And lights off is 88?

If above is correct, which is wild with an ac running, I’d start tweaking the intake and exhaust. Turn off the intake and see how it responds. You may be shoving the cool air right out with the intake going

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I got 84 yesterday with lights on, daytime, AC inside tent, 88-90 AC outside tent exhausting out window.
Today, I got 95 light on, daytime, ac inside. 88 with light off, daytime, ac inside.

Another question, where are your readings being taken? Are they at canopy level?

I have no plants growing inside yet, so im taking my readings from on top of the buckets

im going to take the AC out of the tent and try cooling the lung room down again. Maybe it’ll be better with the lights on at night and off during day.

I’m just confused as how the temps are hitting that high with an ac. I ran a tent in my garage, which is 85* most of the year, and added an ac unit. The highest temp recorded was 82 with lights on.


Im thinking it mightve been the ambient temp from the lung room that making it so hot, because today was a hot day and I don’t have central AC so that room tends to get pretty warm on hot days.

Ive taken the AC out, and have it in the room with it exhausting out the window. The room itself now feel much much better, but with lights on now, the temp inside the tent has went up to 95.
Im hoping itll drop significantly in an hour or something because ive only had the AC on cooling the lung room for about 20 minutes now.

@Countryboyjvd1971 @Donaldj

Ok, Old HVAC guy here…

Are you exhausting the tent into the room? If so, that’s your problem. You have to exhaust to a different room or the attic… or outside.

You can’t recirculate your tent exhaust back into the tent.

And the AC has to exhaust outside, no exceptions.


What kind of light are you running?

I am exhausting the inline fan into the room, and AC is exhausted to the outside. Night time with lights on right now, im at 90F

I cant exhaust the inline fan into another room because i have to keep the door closed so the AC can do its job.

You have to find somewhere else to blow it. Have to. This problem won’t go away.

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