Tent 15 degrees hotter than room

Hey all, my 4x4 grow tent is about 75 right now and the room that the tent is in is 60. I know 75 is a great temperature, but from my understanding the tent should be no more than 5 degrees hotter than the room that it is in. Does this mean that i possibly do not have everything set up right? I suppose i could have the 400 cfm inline fan inside the tent instead of out. Could i connect my inline directly to my air cooled hood? I am using a 600watt bulb.

Any thoughts?
Thanks a lot for the help!

Do you have a filter on there? If you're just getting started take it off and just vent straight out and see if the temps go down.

I am using a carbon filter at the top of the tent. Ducting runs from the filter down to my my light which is connecting to more ducting that runs to a 400cfm(on outside of tent) and into the attic. I dont have to worry too much about smell since every neighbor around me grows and the air outside smells like herb. I also dont want my house always smelling strong.

Yeah - it was just a temporary thing for testing. I know we all have to use filters. Look - I'm pretty sure you're going to have to increase the CFM if you've got that kind of temp diff. Or live with it. I have that kind of setup where temps are higher like that and just keep the main room cool. Of course - that's not easy for everyone to do but in the winter it's usually doable.

Yeah man, i have quite a long winter here so i think it will be super easy to maintain the ideal temperatures. I was just surprised at the huge temp difference between my room and my tent. I thought that after doing a lot of research i had it down, knew the right supplies to get, and the temperatures would only vary from 1-10 degrees. Unfortuantely i am stuck with the fan that i have now and will have to figure something else out. I think i will move the inline closer to the hood. Do some people connect their exhaust fans directly to the air cooled reflector, or would i need to have at least a little bit of duct because 6" fan and a 6" hood would be an issue because they are exactly the same size?

bioWheel said:

Yeah - it was just a temporary thing for testing. I know we all have to use filters. Look - I'm pretty sure you're going to have to increase the CFM if you've got that kind of temp diff. Or live with it. I have that kind of setup where temps are higher like that and just keep the main room cool. Of course - that's not easy for everyone to do but in the winter it's usually doable.

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Not sure - I use LED's. Someone will tune in.

Here is a picture of the set up

Your going to get the same answers as last week when you asked. Like everyone said before, it's fine.

"Your understanding" that it's only going to be 5 degrees hotter is wrong.

Think you'll see better flow and lower temps as you raise the light. Air flow is restricted a bit with every turn.

i dont see an intake or an exhaust, but just an air cooled lamp.

try either taking the glass out of the hood or adding in more holes (looks like they already have some there for you) throw a honeywell in there or something

i always put the exhaust high and the intake low, on opposite sides of the tent.

you think its kinda hot now running MH light........wait until you run the HPS light. lol better get an ac unit AND a fan to blow the "hot pocket" that get trapped below the hood and above the tops of the plants. I ran 10* hotter when running hps vs mh. so I had to invest in an ac unit. now I run 72* lights ON and lights OFF (ac only runs when lights on, and ambient temps in my basement are 73*).

bioWheel said:

Think you'll see better flow and lower temps as you raise the light. Air flow is restricted a bit with every turn.

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^ this...

you could get some hardpipe 90's to come out of the hood, that would reduce the blockage of air some, but your cfms drop every time you make a corner. there's a formula somewhere but I can't remember it.... its been awhile since I've done HVAC work.

Theres a lot of bending in the ducting and its quite long. The more obstructions and length the more difficult it is for the fan to do its job. Ive done a lot of reading and I never heard about that 5 degree difference thing, but regardless your temps in your tent are fine. I wouldn't stress about it. Also in my setup I have 2 400 watt HPS in a little bigger tent and the same fan and my temps stay perfect at 75-80. I have my filter standing straight up inside at the corner of the tent and the fan just sits right on top, and then I have flexducting from the fan going out the tent into the attic. On the other side of the tent I took duct and I brought it to my closest window and just sits right under the window. The window is cracked open a little so it gets the cold air from out side and since its right under the window and the shade is shut no one can see it. Either way good luck man. If it isn't broken don't fix it. WHen your temps start getting out of control then fix it, but for now don't stress. Stress causes grey hairs and cancer.

COflower said:

Hey all, my 4x4 grow tent is about 75 right now and the room that the tent is in is 60. I know 75 is a great temperature, but from my understanding the tent should be no more than 5 degrees hotter than the room that it is in. Does this mean that i possibly do not have everything set up right? I suppose i could have the 400 cfm inline fan inside the tent instead of out. Could i connect my inline directly to my air cooled hood? I am using a 600watt bulb.

Any thoughts?
Thanks a lot for the help!

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As some others mentioned, try to keep your ducting as short and with as few bends as possible. Try lowering your carbon filter, I see that you have it way up high to the ceiling. You could easily shorten the ducting several feet there by putting it closer to the level of the reflector. Heat rises too, so with that in mind you're actually pulling hot\warm air in thru your carbon filter, when it would be better to pull in cooler air either from ground level or outside. Also, the source of your odor is going to be your plants, so to me it makes sense to keep it lower for that reason as well.

Keep the inline fan outside the tent, as close to the actual exhaust as possible. You don't want to put it inside your tent and attempt to push all of the hot air thru the ducting, as that would be terribly inefficient. You want to pull the air as much as possible instead.

Something else I see is that outside of the tent at the exhaust end you have the ducting slope downward, and it is pulling hot air (which naturally wants to rise)... you don't want it to roller-coaster like that. Imagine the air as if it was water going through the ducting.

Now, the temperature difference between the inside of the tent and the room the tent is in will depend on quite a few things, including the efficiency of your ventilation, what your lighting is, and the ambient temperature outdoors. The Cannabis doesn't know that the temperature inside the tent is more than 5 degrees hotter than outside the tent.

I have two 600 watt lamps inside my tent, which is 4.5' x 4.5' x 6.5', and a similar scenario in which I have a carbon filter inside the tent and exhaust outside the tent into the attic (where the inline is). The temperature inside my tent is heavily dependent on the temperature outdoors, not just the ambient room temp. Right now for example it is relatively warm outside, 60F, and my room is about 78 with the temp inside the tent at canopy level (tent flaps open) around 82F. When it gets colder outside the temperature in the tent will go down to the low 70's. I use a speed-controller with my inline fan so it doesn't run at max when it is below 40 outdoors.

Nizza said:

i dont see an intake or an exhaust, but just an air cooled lamp.

try either taking the glass out of the hood or adding in more holes (looks like they already have some there for you) throw a honeywell in there or something

i always put the exhaust high and the intake low, on opposite sides of the tent.

Click to expand...

Intake essentially IS the carbon filter, exhaust is outside of the tent... doing it like this will create a negative pressure within the tent, which will draw fresh air into it. If he was to remove the glass lens from the reflector it might potentially just make matters worse (it would also bypass the filter).

You'll notice as your plants get bigger your temps get higher.
Your foliage traps a lot of the heat from your lights.

If you want to run cooler you need to exchange more cool air with more CFM's