Air condition question

BobCajun

BobCajun

Well-Known Member
BiG $m0k3 said:
How many BTUs do I need for a portable air conditioner in a 4 x 4 x 8 grow tent?
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The smallest one available, which appears to be 8000 btu. The air coming out is going to be very cold though. You mean the ones on wheels that use air ducting right?
 
Gquebed

Gquebed

Well-Known Member
Depends what youre using for a light. 1 x 1000w air cooled probably 4000 btu should do it. Open bulb 1000w will need 6000btu minimum.

But in a 4x4x8 with an air cooled 1000w you should be able to get away without a/c if you set up exhaust right and dont live in a hot hot climate...
 
BobCajun

BobCajun

Well-Known Member
Just make a solid top for the tent and cut a hole slightly smaller than the fixture and sit it on top. Putting the heat sinks inside the chamber is pretty crazy really. Mine is outside the top, 240w CXB high bay array. Works perfect. All I need for ventilation is a 4" PC fan and another one blowing over the tops. Not hot at all inside, but the heat sink outside is so hot you wouldn't want to hold your hand on it. It would be like having an iron inside the tent, or a hair blower if it's a fan type. Why would anyone want that when there's an easy way to avoid it? So the tent has a hole in top, big deal. Just tape it shut again if you don't like the external fixture after all and want to heat things up again, like in winter maybe.

I just used cardboard to strengthen the top, btw, and reinforced the parts where the fixture would sit, by running steel shelving support bars across.
 
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BiG $m0k3

BiG $m0k3

Active Member
Gquebed said:
Then you shouldnt need any ac at all. Your exhaust fan/filter should keep it cool enough...
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That's what I thought. but it still hits 85 degrees. I'm a beginner but isnt 85 Degrees too hot. I'm running my lights at night now which helps. But in the daytime when I come home and check the hygrometer it reads 82 to 85 degrees sometimes. Is that anything to worry about? Humidity is 40 to 60% usually. Because the humidity is good already, I wouldn't need a swamp cooler right? Because that would cool the tent and raise the humidity. Is the air conditioner the best way to solve this? or am I worrying too much?
 
Gquebed

Gquebed

Well-Known Member
BiG $m0k3 said:
That's what I thought. but it still hits 85 degrees. I'm a beginner but isnt 85 Degrees too hot. I'm running my lights at night now which helps. But in the daytime when I come home and check the hygrometer it reads 82 to 85 degrees sometimes. Is that anything to worry about? Humidity is 40 to 60% usually. Because the humidity is good already, I wouldn't need a swamp cooler right? Because that would cool the tent and raise the humidity. Is the air conditioner the best way to solve this? or am I worrying too much?
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82 to 85 is a little high, but not tragic. Least try to get it below 80. Maybe a bigger fan/filter combo.
Humidty is good where it is...dont want that getting any higher... dont know anything about swamp coolers.

If you can afford ac, then why not go for it? A few extra bux to get ideal temps will do wonders at harvest...
 
Rasta Roy

Rasta Roy

Well-Known Member
I run in the 80's...but I use co2...

But @Gquebed has the right of it...if you can afford the ac I'd go for it. Being able to run ideal temps and being able to dial in the perfect environment will only reward you in the end.
 
coldrain

coldrain

Well-Known Member
BiG $m0k3 said:
That's what I thought. but it still hits 85 degrees. I'm a beginner but isnt 85 Degrees too hot. I'm running my lights at night now which helps. But in the daytime when I come home and check the hygrometer it reads 82 to 85 degrees sometimes. Is that anything to worry about? Humidity is 40 to 60% usually. Because the humidity is good already, I wouldn't need a swamp cooler right? Because that would cool the tent and raise the humidity. Is the air conditioner the best way to solve this? or am I worrying too much?
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Never use a swamp cooler in a grow room. They raise the humidity by a lot and you really don't want your humidity to ever be more than 40-50%. I like to keep my humidity around 40% if not a little lower since I'm terrified of getting powdery mildew. 85 degrees isn't too hot, but it's getting pretty close to the danger zone. Studies have shows that the plants stop photosynthesizing when the temperature gets above 86 unless there is supplemental CO2 involved. If you're using CO2 then 85 degrees is just about perfect and you can even go a little warmer. I try to keep my grow room at 78-80. That's pretty optimal. I live in an area where it gets pretty hot in the summer though and I'm growing in a garage. The garage is insulated and sheet rocked and I built a 12x8 room inside the garage that I use for flowering. I run a 8000btu AC unit that barely keeps the room cool enough during the summer when I'm using 2 x 1000W. Right now I'm seeing the temps reach 86 at times, but the plants are currently vegging and the thermometer is at eye level in a corner of the room where there is minimal airflow, so the temperature near the ground where the plants are hanging out is definitely not getting anywhere near 86. That's another thing to watch out for. A buddy of mine was shitting his pants the other day because his room was hitting 90 degrees. I noticed that his thermometer was hanging from the ceiling and that explained it right away. He moved it to near floor level and it immediately dropped to 83..... still just a tad warm, but within the acceptable range.

In a 128 cubit foot grow tent you probably don't even need a separate AC unit unless the room that the grow tent is in is hot. Good ventilation should be enough.
 
BiG $m0k3

BiG $m0k3

Active Member
coldrain said:
Never use a swamp cooler in a grow room. They raise the humidity by a lot and you really don't want your humidity to ever be more than 40-50%. I like to keep my humidity around 40% if not a little lower since I'm terrified of getting powdery mildew. 85 degrees isn't too hot, but it's getting pretty close to the danger zone. Studies have shows that the plants stop photosynthesizing when the temperature gets above 86 unless there is supplemental CO2 involved. If you're using CO2 then 85 degrees is just about perfect and you can even go a little warmer. I try to keep my grow room at 78-80. That's pretty optimal. I live in an area where it gets pretty hot in the summer though and I'm growing in a garage. The garage is insulated and sheet rocked and I built a 12x8 room inside the garage that I use for flowering. I run a 8000btu AC unit that barely keeps the room cool enough during the summer when I'm using 2 x 1000W. Right now I'm seeing the temps reach 86 at times, but the plants are currently vegging and the thermometer is at eye level in a corner of the room where there is minimal airflow, so the temperature near the ground where the plants are hanging out is definitely not getting anywhere near 86. That's another thing to watch out for. A buddy of mine was shitting his pants the other day because his room was hitting 90 degrees. I noticed that his thermometer was hanging from the ceiling and that explained it right away. He moved it to near floor level and it immediately dropped to 83..... still just a tad warm, but within the acceptable range.

In a 128 cubit foot grow tent you probably don't even need a separate AC unit unless the room that the grow tent is in is hot. Good ventilation should be enough.
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Thanks for the advice on the swamp cooler. My hygrometer is hanging towards top of tent. Im gona try and lower it closer to my plants.
 
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