Cooling a Hot Grow Tent

Greetings, Brethren - I've got a 4X4X8 grow tent in my un-air-conditioned garage in Central Florida. There's a 1000W Cool Tube running 12/12 with a 400 CFM fan on one end exhausting to the garage. There are also two 250 CFM duct fans blowing air in from the garage, so there's lots of air exchange and the tube is not hot to the touch. That said, it's getting warmer down here and the ambient temp in the garage is 85-90F during the day, with the temp in the tent pretty much the same. I know this is too hot and will reduce my yield, so I gotta cool things down. Question: Is a small portable air conditioner the way to go here? If so, recommendations on make & model? I'v seen 12,000BTU units for about $300USD. It's not really an option to install vents in the garage, and the outside temps aren't that much cooler anyway. Thanks!

Walmart has a 5,000BTU for $90 that would work perfect just run some duct off of it to ur grow tent

It's simple and free.. Turn your lights on at night instead of day. The lower ambient night time temps will put you right on target.

PJ Diaz said:

It's simple and free.. Turn your lights on at night instead of day. The lower ambient night time temps will put you right on target.

Click to expand...

That's the smart thing to do.

You can also get a bucket with ice in it, and have a fan blowing on it for a cheap DIY air conditioner

you guys been to south florida at night, in the summer? temps drop 5-10 degrees. that ain't gonna help much.

window units would be the easiest way to go. its not the most economical but they are initially cheaper and easy to replace. freidrichs makes the best. lg and samsung are good and cheaper. figure out the sq. ft. of your entire garage and get the biggest a/c you can. there's no harm in overdoing the a/c.

also, if your hot water heater happens to be in your garage. get it an insulated jacket. otherwise it's only adding to the heat in the garage.

Thanks, y'all for the suggestions.

Well, the quick 'n easy fix is clearly the first thing to try - just set the tabs differently on the light timer. Never thought of that. Question: Will a one-time over-long "day" bother the girls, or should I give them 12 extra hours of darkness when making the transition?

If it's still too hot, the best deal I've found for a portable AC is here:

http://www.compactappliance.com/AP12000S-EdgeStar-Extreme-Cool-12000-BTU-Portable-Air-Conditioner/AP12000SOB,default,pd.html

It's low-maintenance, you don't have to worry about emptying the condensate tray. Since it can't go in the tent, I'd have to set it just outside and make a cardboard plenum to adapt the output louvers to 6" duct to run into the tent, but that's it. The heat can exhaust into the garage - it gets opened often enough that it shouldn't be a problem. And the price is right at $279USD, free shipping. It's an open-box deal, warranty intact. I couldn't find that $90 Walmart deal, just a $140 window unit, but this looks pretty good, worth the extra bucks IMHO.

From what I've read about inexpensive evaporative coolers, they're not worth the trouble. No guts.

The bucket-of-ice won't due for me - I'm just not reliable enough to remember to change it. Besides, the ice-maker in my refrigerator almost certainly couldn't keep up, and then I'm running out to buy ice all the time. Not practical for me, but thanks for the suggestion.

typoerror said:

you guys been to south florida at night, in the summer? temps drop 5-10 degrees. that ain't gonna help much.

window units would be the easiest way to go. its not the most economical but they are initially cheaper and easy to replace. freidrichs makes the best. lg and samsung are good and cheaper. figure out the sq. ft. of your entire garage and get the biggest a/c you can. there's no harm in overdoing the a/c.

also, if your hot water heater happens to be in your garage. get it an insulated jacket. otherwise it's only adding to the heat in the garage.

Click to expand...

Typo, your post popped just as I hit Submit on the last one. Good thoughts; the night air isn't really all that much cooler. I plan to just blow cold air into the tent, rather than cool the garage, which is not insulated and gets opened several times a day. Only thing I'm not sure about is air exchange - the CFM of the AC is unknown, and I want to balance the guzinta's with the guzouta's. (Goes-into vs Goes-out-of). I may have to replace the 400 CFM exhaust tied to the cool tube with a 165, and hope the cooler air makes up for the slower airflow. Even at 165, the whole volume of the tent is exchanged once a minute.....

sounds like you've got a plan. it will take some tinkering but you should be able to get it dialed in.

PJ Diaz said:

It's simple and free.. Turn your lights on at night instead of day. The lower ambient night time temps will put you right on target.

Click to expand...

That's what i do...LOL

Sorry but a garage that is constantly air conditioned is suspicious as hell... you dont think the neighbors will notice it go for it, but I know if my neighbor had an AC unit running in his garage / shed I would be like WTF he got going on in there.

tpsmc said:

Sorry but a garage that is constantly air conditioned is suspicious as hell... you dont think the neighbors will notice it go for it, but I know if my neighbor had an AC unit running in his garage / shed I would be like WTF he got going on in there.

Click to expand...

Thanks for the concern, tp - I try to be cautious and fly under the radar. The plan here is to set this small roll-around style portable AC unit next to the tent and let it blow directly into the tent through 6" duct. Both the tent exhaust and the AC exhaust are straight into the garage, which is opened and closed several times a day. We'll have to see if cooling the tent down from 85F to 75F will raise the average ambient temp in the garage significantly. Since the garage is an attached, large 2-car variety, I'm hoping it wont. As you say, the last thing I want is to draw my neighbors' attention.

Sativa likes those temps, if you wanted to go that route instead. You have indica?

Portable AC is a good idea, like one of those units on rollers that have their own vent tube and window panel.. End of tube has to go outside the tent.. I worked at this one company that had a little server room that gets too hot, and the fuckers decided how to install a window AC by basically just sitting it in the room, so the front and back are both exposed to same environment. Retards. Just so there is no confusion, AC separates the heat from the front to the back, and its gets hot in the back, and the sum of both (front and back) is warmer than without the AC (because electric current creates heat as a waste product, always, although it approaches zero when using superconductors).

James87 said:

Sativa likes those temps, if you wanted to go that route instead. You have indica?

Portable AC is a good idea, like one of those units on rollers that have their own vent tube and window panel.. End of tube has to go outside the tent.. I worked at this one company that had a little server room that gets too hot, and the fuckers decided how to install a window AC by basically just sitting it in the room, so the front and back are both exposed to same environment. Retards. Just so there is no confusion, AC separates the heat from the front to the back, and its gets hot in the back, and the sum of both (front and back) is warmer than without the AC (because electric current creates heat as a waste product, always, although it approaches zero when using superconductors).

Click to expand...

Thanks, James, all exactly on point. The girls are mostly G13 Haze, 80% indica, so I want to keep them a bit cooler. I'm also an IT guy, and the idea of portable AC came from some old issues I had with a hot server room. And you're exactly right - There Ain't No Such Thing As A Free Lunch (TANSTAAFL) - if cool air is coming out one hole, then the heat that was extracted from it has to go out another, plus waste heat from the motor/compressor. I plan to exhaust the AC's hot air into the garage (there's no window within easy reach of the tent), which is big and well ventilated by frequent opening and closing of the overhead door. Ciao!

I found that a whirlybird?? (not sure if that's what they call it outside of OZ) Helped drag some air from my garage and in turn cooling the garage and grow tent. Just a thought

tpsmc said:

Sorry but a garage that is constantly air conditioned is suspicious as hell... you dont think the neighbors will notice it go for it, but I know if my neighbor had an AC unit running in his garage / shed I would be like WTF he got going on in there.

Click to expand...

Why would you air condition the garage? Air condition the grow tent and worst case IF the garage gets too hot from the AC just duct hot air out bringing fresh air in (which can be done with nothing coming out of your window/garage)

Flash4211 said:

Thanks, James, all exactly on point. The girls are mostly G13 Haze, 80% indica, so I want to keep them a bit cooler. I'm also an IT guy, and the idea of portable AC came from some old issues I had with a hot server room. And you're exactly right - There Ain't No Such Thing As A Free Lunch (TANSTAAFL) - if cool air is coming out one hole, then the heat that was extracted from it has to go out another, plus waste heat from the motor/compressor. I plan to exhaust the AC's hot air into the garage (there's no window within easy reach of the tent), which is big and well ventilated by frequent opening and closing of the overhead door. Ciao!

Click to expand...

IF you get a portable AC ALWAYS get a dual hose one. Single hose will create way too much negative pressure in your grow tent and will just constantly bring hot garage air in.