Room still hits high temps with intake and outtake fans, any ideas?

Thread starter #1
So someone told me to get another fan so it'll cool the room more. So I added one more so I have a intake and outtake fan. However the grow box seems to still get high temps even thought it's better then before it's still too high in my opinion. The box reaches 97F max, I don't want my plants to die because of this, they're 11 days old. Here is my setup.



Plants look healthy because I was growing them on the windowsill when I was gone for 2 days. Now I'm back and I want them in the grow box because I can't have them visible to the public.(I don't want neighbors to tell me I'm a bad influence to their kids)

Huge thanks to all :3:
 

Antics

420 Member
This will help you in correctly uploading and adding images to your post: http://www.420magazine.com/forums/p...lery-guide-how-resize-upload-post-photos.html

As for your setup:

You don't need an intake fan. This is operating the same as having one exhaust fan. Remove the intake fan, and put it at the top as another exhaust fan.

Your lights are too far from your plants. 1-3" / 2.5-7.5cm from seedlings. You will need more lights later in Veg, and will need more lights later in Flower. I suggest 100w per plant in Veg, and 150w per plant in Flower. These are minimum wattages that I suggest, and are actual wattage ratings, not the "equivalent" number.

Foil is not a good wall cover. It can create hotspots which can burn your plant. Flat white is a good color, reflective mylar works great, and if you have to use foil, use the dull side.

Your containers are clear plastic, cover the sides of them with tape or something. Light is not good for plant roots. You will also want to transplant later on.
 
Thread starter #3
This will help you in correctly uploading and adding images to your post: http://www.420magazine.com/forums/p...lery-guide-how-resize-upload-post-photos.html

As for your setup:

You don't need an intake fan. This is operating the same as having one exhaust fan. Remove the intake fan, and put it at the top as another exhaust fan.

Your lights are too far from your plants. 1-3" / 2.5-7.5cm from seedlings. You will need more lights later in Veg, and will need more lights later in Flower. I suggest 100w per plant in Veg, and 150w per plant in Flower. These are minimum wattages that I suggest, and are actual wattage ratings, not the "equivalent" number.

Foil is not a good wall cover. It can create hotspots which can burn your plant. Flat white is a good color, reflective mylar works great, and if you have to use foil, use the dull side.

Your containers are clear plastic, cover the sides of them with tape or something. Light is not good for plant roots. You will also want to transplant later on.
Alright, I'll flip the intake fan so it'll be and outtake fan. Yes I know I will need more lights, I'm planning on adding more lights for when they are 2 weeks old. For the foil, I just havn't had the money to go out and buy it yet. I plan ony buying Mylar, but how much will it bring the temp down?
 

Antics

420 Member
No no no! Don't forget heat rises. Using the fan at the bottom won't make much difference in your temps.
As for how much difference this will make? I don't know all the math and formulas involved in calculating CFM vs. Temp, ambient temp etc.. to find the resulting temperature. I know the basics of heat rises, more fans = more air flow.

Leave the bottom hole there as a passive intake. I strongly suggest cutting a new hole at the top, and installing the exhaust fan there.

Even with a few bulbs, they still need to be closer. The plants will stretch too much being this far away. 2.5-7.5 cm distance between bulb and leaf.
 
Thread starter #6
Alright, I just finished doing the changes.



I'll monitor the temp and report back with the updated temps. Hope this does it :3
 
Last edited by a moderator:

Obi Wan

Well-Known Member
Rather than moving the plants up into the warm air to reach the light, can you move the light down? That may help keep the plants awash in fresh intake air and increase available light. I might also suggest turning the CFL to a horizontal position above the plants. It wont help with the heat but will provide the most light to your plant.

97F is pretty toasty. You might want to keep the plants on the window sill until you can optimize your closed environment for 24-48 hours.

Could you make a small tunnel or tube to direct your passive fresh air to the opposite side of the box from your exhaust? I worry that fresh air is coming in and going straight up and out the exhaust without cooling the box.

/Obi Wan
 
Thread starter #9
Right now the temp is at 86F when my room is at 83, I think it'll hold until I get Mylar. I put the lights in a horizon like you said just right now. Their is holes on the top of the box so it can get air from the top and I also have the holes in the back and on one of the sides of the box. I don't think I'll need a tunnel.
 
If you can cool down the room your cabinet will cool down as well. You will never get the cabinet cooler with 83 degrees in the room. Lights and electricity usage equals heat. No amount of fans will cool that cabinet with the room temp that high.
 
Thread starter #12
I know I'm going to need more bulbs, I have them it's just that I'm not going to add them until the 2nd week. Also because I don't have the Y splitters.
 
Thread starter #13
I know, I turned on the AC and it the box is now at 83F. It should start getting cold in about 3 weeks, so I shouldn't have to deal with this problem for much longer.
 

deki

New Member
how much is the temp outside the tend where you pick up the fresh air? you need to have at least 10/15 degree less to be sure that you can cool down the temp in the tend
 
Thread starter #15
how much is the temp outside the tend where you pick up the fresh air? you need to have at least 10/15 degree less to be sure that you can cool down the temp in the tend
It's not a tent, it's a wooden box. outside it depends on the time of day, but today it'll be at high 87F and a in the low 50s at night. My window is open at night so it should cool down my room.
 

Antics

420 Member
If you can cool down the room your cabinet will cool down as well. You will never get the cabinet cooler with 83 degrees in the room. Lights and electricity usage equals heat. No amount of fans will cool that cabinet with the room temp that high.
Mac is absolutely right. You need to cool down the air in the room.

Or you have the option of using a fan blowing on a bowl of ice, but you'll need to replace this constantly. But.. it'll work.
 
Thread starter #18
Yes, I was doing frozen blocks of ice in the past to keep the box cool, but sometimes I'd be out for school all day and I wouldn't be home to replace it. However I can just make a swamp cooler, and just connect it to the box.