Grow Tent is 104 Degrees Farenheit

Setup is a 4X4X6 tent with 600W HPS 4" intake and 4" exhaust. It is mylar inside from top to bottom. When the light ran for 12 hours the temperature reached 104F. The HPS light is currently being substituted with two 12" x 12" LED panels which work great for veg, but not so great for flower. I am conflicted because I will either be buying a window AC unit or a 4 bulb T-5 setup which are comparable in price. My conflict lies in that the HPS running in tandem with the AC will be killer on my electric bill, but I'm not sure if the T-5 would be produce sufficient yields. The strains are autoflower so any loss in yield would blow. What would you do? Would the additional cost of running both an HPS light and AC be worth the extra yield, or would using a T-5 at a much lower energy cost be worthwhile in the long haul? Suggestions appreciated!

If you look for the next thread(it's directly under where I'm posting now) it talks ab out water cooling equipment. Hope that helps

Are you using an air cooled hood for the light? I wouldn't worry too much about adding an a/c to your bill. A 600w running 12/12 costs like $25 a month and adding enought a/c to that will cost another $25 a month MAX. Aren't you saving more then that growing your own?

If your growing some kush they'll feel right at home like there in Afghanistan

Change to 6"or even 8'' vents and up the CFM rate of the fan/fans.

definately need a higher CFM fan. That 4" is prob around 200CFM. Get a 6" or even 8" anywhere from 400-600 CFM.

Your fan doesn't have enough airflow to cool.

Thanks for the suggestions. I will probably go with the AC since changing my intake and outake would require buying a larger carbon filter as well. I do have a 6" inline I bought for this project but it is too loud and too powerful. It makes the tent swell like a balloon b/c the centrifugal fan and carbon filter are both 4", which is what was suggested in HT for this size setup. I used the same 600W HPS in a 6x3x6 closet previously with 3" fans a few years ago and the temp never got above mid 80s. This tent thing is a whole other ball game.

Hucklberry said:

Change to 6"or even 8'' vents and up the CFM rate of the fan/fans.

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I hear ya, but my setup is less than 100 cubic feet. Theoretically I should be able to replace the air twice per minute with 200 CFM. Since this is a tent and the old air is pushed into the room right outside the tent (rather than into the attic like my previous project) I believe this is resulting in higher overall temps since the hot air has nowhere else to go. I was hoping by using a tent I wouldn't have to cut any holes in this new house. Do you think it would help (enough to bring temps down to the desirable high 70s range) if the exhaust went into the attic instead?

As solely intake and exhaust fans those 4" ones are just fine. I think some people are confused and thought you were using 4" fans and ducting for your air cooled hood. Are you? If so, then changing those eill be more expensive than an a/c (hood, fan, filter, ducting) but will help a lot. A 600w light should be air cooled through a 6" hood; especially in a tent. If you can get the a/c though you should be fine.

View attachment 2108241
Maybe this will help illustrate what I'm working with. I did some price shopping and the "air cooled hood only" will run me around $70 on the low end. How much of a difference in temperature can I really expect if I were to go this route?

Wonder Boy said:

View attachment 2108241
Maybe this will help illustrate what I'm working with. I did some price shopping and the "air cooled hood only" will run me around $70 on the low end. How much of a difference in temperature can I really expect if I were to go this route?

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You have to repost that picture. The link doesn't work.

If you air cool your hood you MIGHT be able to get by without an a/c unit at all. Air cooling your hood will literally take the majority of the heat out of your tent. Get a 6" hood and use the fan that you have. Pull air through the hood from outside of the tent and exhaust back out of the tent. Try and make the ducting as straight as possible. Test that out and I bet you see a 15+ degree drop on temps.

Running an AC is going to cost alot more. ust run the 6" you got. Its loud because it's moving soo much air. Use the carbon filter you got, or buy one with the matching cfm. Will save you money in the long run w/o running an AC unit.

Bluntcuts said:

Running an AC is going to cost alot more. ust run the 6" you got. Its loud because it's moving soo much air. Use the carbon filter you got, or buy one with the matching cfm. Will save you money in the long run w/o running an AC unit.

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Running an a/c might be inevitable though. Gotta see where those temps drop to after he puts the air cooled hood in.

phillipchristian said:

Running an a/c might be inevitable though. Gotta see where those temps drop to after he puts the air cooled hood in.

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This is true. But if he run a 6" 400cfm fan. It should be enough

phillipchristian said:

You have to repost that picture. The link doesn't work.

If you air cool your hood you MIGHT be able to get by without an a/c unit at all. Air cooling your hood will literally take the majority of the heat out of your tent. Get a 6" hood and use the fan that you have. Pull air through the hood from outside of the tent and exhaust back out of the tent. Try and make the ducting as straight as possible. Test that out and I bet you see a 15+ degree drop on temps.

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I agree with you Wonder Boy. As I stated above. Just gotta wait and see though. Every room and environment is different.

I really do appreciate all the help guys! I've been researching air cooled hoods and I'm going to make my own air cooled tube hood using the Bake-A-Round pyrex tube. I did not expect so much trouble keeping the temps down since this equipment was previously used in a closet environment with absolutely no heat issues. I believe I may have underestimated the efficiency of mylar. I will create a DIY Guide when constructing this tube hood and post it here to help others in the same situation. Thanks again guys. I will report back with results (and hopefully MUCH lower temperatures).

Wonder Boy said:

Thanks for the suggestions. I will probably go with the AC since changing my intake and outake would require buying a larger carbon filter as well. I do have a 6" inline I bought for this project but it is too loud and too powerful. It makes the tent swell like a balloon b/c the centrifugal fan and carbon filter are both 4", which is what was suggested in HT for this size setup. I used the same 600W HPS in a 6x3x6 closet previously with 3" fans a few years ago and the temp never got above mid 80s. This tent thing is a whole other ball game.

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Swell like a balloon? You should be pulling air out of the tent, not pushing air in.

brotherjericho said:

Swell like a balloon? You should be pulling air out of the tent, not pushing air in.

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Sometimes you actually need an active intake.

brotherjericho said:

Swell like a balloon? You should be pulling air out of the tent, not pushing air in.

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There is a 4" centrifugal fan exhausting the air through a carbon filter, so when I tried to use the 6" intake fan it was bringing in more air than the 4" could push out. All this equipment was previously used in closet and worked fine. I tried to adapt it all to a tent (cause I was tired of not being able to hang my clothes) but the transition has not been as smooth as I had hoped.

just open the tent .