Im having a problem maintaining the temperature down, i have a 3x3 tent with a 400watt hps light which im running at 75% output and an inline fan blowing air in and one blowing air out, and i cant keep the temp below 87F Any ideas on how to control that? or is the light just too strong for a small of a place?
Keeping the temperature down?
- Thread starter AZ007
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What is the CFM of your exhaust fan
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- #3
I found that the problem was the temperature in the room itself, even tho i had constant air going in and out the air temperature wasnt cool enough to keep the tent cool. So what i had to do was i lowered the ac in the room, and i had to open the tent a little bit, so now i have cold ac air going in there and the temperature stabilized at 82-84F at 100% output
Fuzzy Duck
Well-Known Member
Mmm if you can provide the size of inline fan, model/brand also height of the grow tent...
Some calculations can be done to see if its suitable for your needs !
Other wise a possible suggestion which comes at a price/improvement is using an air cooled hood
Some calculations can be done to see if its suitable for your needs !
Other wise a possible suggestion which comes at a price/improvement is using an air cooled hood
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- #6
Mmm if you can provide the size of inline fan, model/brand also height of the grow tent...
Some calculations can be done to see if its suitable for your needs !
Other wise a possible suggestion which comes at a price/improvement is using an air cooled hood
Its a 6" 240 CFM air duct inline fan blowing air in, and i have one of them Lasko 6" 2 speed clip on fans blowing air out, its a small area of only 36X20X60
Fuzzy Duck
Well-Known Member
Blowing air in does not really lower temps !
Use the fan for extraction if you wish to see a noticable difference in temperature drop, placed at the top of tent/growing area as warm air rise's
You may wish to look at using or improvising a passive vent at base of the tent/growing for an intake...
You might want to turn the fan speed up to high also... but feel free to play around with both settings to observe difference in temp control.
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- #8
Blowing air in does not really lower temps !
Use the fan for extraction if you wish to see a noticable difference in temperature drop, placed at the top of tent/growing area as warm air rise's
You may wish to look at using or improvising a passive vent at base of the tent/growing for an intake...
You might want to turn the fan speed up to high also... but feel free to play around with both settings to observe difference in temp control.
So youre saying put the inline fan on top pulling the hot air ou and a fan on the base blowing fresh air in?
goathead
New Member
I utilize the vacuum philosphy. In my opinion by creating a vacuum you can achieve two things at once. i may be wrong cause I am knew to this here way of life. i utilize it in a 14' by 10' chamber. I do not run A/c and barely started using my own co2 generator. I am still tryin to dial in some of my points in my set up. I am really trying not to change to much so I know when things are not right where to change them back. I do not use fans either only the vacumm from the inline 8" fan the flex tube is set up attached to the hood and then out to the last hood .
What kinda hood are you using?
If it's a sealed hood (has a glass plate/tube) then one fan to extract the hot air from the light and one to move the air upward or out from the top.
Lights make heat two ways, the heat coming from the air around the bulb and the objects they heat up. In other words, if you are just moving air thru the light/tube, you are only removing one source of heat.
You should have one fan that pulls air from the light out and one to move air upwards.
Hot air rises, so take the fresh air from the lowest point you can.
What's the temp of the room outside the tent?
If it's a sealed hood (has a glass plate/tube) then one fan to extract the hot air from the light and one to move the air upward or out from the top.
Lights make heat two ways, the heat coming from the air around the bulb and the objects they heat up. In other words, if you are just moving air thru the light/tube, you are only removing one source of heat.
You should have one fan that pulls air from the light out and one to move air upwards.
Hot air rises, so take the fresh air from the lowest point you can.
What's the temp of the room outside the tent?
Fuzzy Duck
Well-Known Member
Yup pretty much...
Exhaust/extraction fans are always placed at the top of the tent/growing area... as hot air rise's, kind of makes sence don't it & thats the stuff you want to remove to help control temps
You don't always need a secondary fan blowing air in... you can get away with a passive vent, some tents come with velcro flap/windows around the base of the tent to act as passive vents... some other growers improvise by using ducting port holes, with a short length of ducting inserted through with some old tights over the ends to make a bug screen.
My own set up carbon filter & inline fan at the top removing odour & heat...
Passive vent at base of tent as the exhaust/extraction fan removes warm air it pulls new fresh cooler air ijn through the passive vent.
You could always use an air cooled hood to achieve greater temperature control if you wish...
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- #12
The temp of the room is usually at 72F, i think thats where the problem is, not cold enough? Inside the tent is at least 10degrees more than that
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- #13
Yup pretty much...
Exhaust/extraction fans are always placed at the top of the tent/growing area... as hot air rise's, kind of makes sence don't it & thats the stuff you want to remove to help control temps
You don't always need a secondary fan blowing air in... you can get away with a passive vent, some tents come with velcro flap/windows around the base of the tent to act as passive vents... some other growers improvise by using ducting port holes, with a short length of ducting inserted through with some old tights over the ends to make a bug screen.
My own set up carbon filter & inline fan at the top removing odour & heat...
Passive vent at base of tent as the exhaust/extraction fan removes warm air it pulls new fresh cooler air ijn through the passive vent.
You could always use an air cooled hood to achieve greater temperature control if you wish...
See i put my setup just like urs fuzzy duck, my inline fan is on top removing hot air, and i put a lil fan on the base helping bring cold air in, but still isnt it enough, when the tent is closed it gets really hot in there the temp jump to like 88, sometimes 90, Only with the tent open and a fan blowin air at it i can maintain between 82-84
Fuzzy Duck
Well-Known Member
I grow in a pretty much the same size tent as yourself including a 400w HPS
On average my own temps are around 26c to 27c / 78f to 80f which can rise depending on season & ambient temps...
As i grow in a spare room i find the temps of that room effects the temps of the growing area, as it rise's in the summer months so do my own grow tent temps which may hit 30c/85f.
Current temps are with in reason tho & should not be to much of a problem for growing, inless it may get hotter where you live then i may suggest Co2...
I can not do much about that to be honest apart from an investment into an air cooled hood which in theory should lower the temps by a few C or several F as you are directly removing the heat from the bulb/hood area.
Other alternatives if not used is...
Night time temps are often cooler than day time temps... in real life.
Switch Lights On period to real life night time & this should lower temps to a more suitable level if ya not tryed it
I've pretty much exhausted all ideas to lower temps at presents apart from the above... inless you have Ac/air conditioning & that it can be changed per room to alter ambient temps ?
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- #15
I grow in a pretty much the same size tent as yourself including a 400w HPS
On average my own temps are around 26c to 27c / 78f to 80f which can rise depending on season & ambient temps...
As i grow in a spare room i find the temps of that room effects the temps of the growing area, as it rise's in the summer months so do my own grow tent temps which may hit 30c/85f.
Current temps are with in reason tho & should not be to much of a problem for growing, inless it may get hotter where you live then i may suggest Co2...
I can not do much about that to be honest apart from an investment into an air cooled hood which in theory should lower the temps by a few C or several F as you are directly removing the heat from the bulb/hood area.
Other alternatives if not used is...
Night time temps are often cooler than day time temps... in real life.
Switch Lights On period to real life night time & this should lower temps to a more suitable level if ya not tryed it
I've pretty much exhausted all ideas to lower temps at presents apart from the above... inless you have Ac/air conditioning & that it can be changed per room to alter ambient temps ?
Lol thx, i appreciate all the help and diff ideas, also i was thinking, how about buying a small ac unit like one of them little ac units they have at home depot for example? i think they can go for like 100 bucks, that would probably keep the temp down to whever i want it no?
Fuzzy Duck
Well-Known Member
Aye i've seen the mini AC portable units around & had a quick look at a few models...
Now i don't have any experience with such but would question its total output of cooled air to the room size you are using it to whether it makes any difference !
Its a fine line to draw to be honest & i would not like to make a suggestion on that... inless other growers have greater experience on this particular matter ?
I'd still be tempted to look at air cooled hoods tho & mildly cheaper to set up
Providing all warm air is vented from room which the grow tent is situated in to prevent recirculation of warm air !
The temps inside that tent will be affected by the temps of the room your drawing air from. Your fan moves a certain volume of air each minute. In that same minute, the light is putting out an amount of heat energy. Colder air can "absorb" more heat than warmer air. The colder the air is coming in, the more it can cool the lights as it passed through the tent. You're only options are to improve air flow, or lower the ambient temperature outside the room.
I have a couple questions to help address the issue. First, where is that exhaust blowing? Is it just venting back into the room the intake draws from? If so, you're just heating up the room, and the fan will slowly become less effective. Make sure that hot air is getting vented out of the room completely.
Where and how are you measuring your temperature?
80F is not that hot. Sure, it's at the upper limit of where you want to be, but the plants can usually handle it if that's their only stress. The temperature can vary drastically within a grow space. You might also want to corroborate the temp reading with a second thermometer. I recently sealed my room, and I was stressed out that the temps were too high. What I found last night is that things were not as warm as I thought, and that the crappy walmart thermometers suck.
I have a couple questions to help address the issue. First, where is that exhaust blowing? Is it just venting back into the room the intake draws from? If so, you're just heating up the room, and the fan will slowly become less effective. Make sure that hot air is getting vented out of the room completely.
Where and how are you measuring your temperature?
80F is not that hot. Sure, it's at the upper limit of where you want to be, but the plants can usually handle it if that's their only stress. The temperature can vary drastically within a grow space. You might also want to corroborate the temp reading with a second thermometer. I recently sealed my room, and I was stressed out that the temps were too high. What I found last night is that things were not as warm as I thought, and that the crappy walmart thermometers suck.
Those ac units probably are not a good idea since they work with water as a heat exchanger and it slowly blows into the atmosphere making your room extremely humid, and they don't really cool much unless you're standing directly in front and that's because you get the moist air blown in your face. So I wouldn't recommend it.
I'd suggest lights on at night so temps will be cooler. Also try to get an exhaust for the room in addition to the one you're using for the hoods. See if you can improve on the intake of cool air. In my system I have a fan blowing hot air out of the chamber directly to the outside but the intake fan takes air from inside the room so temps stay below 28° during lights on.
I'd suggest lights on at night so temps will be cooler. Also try to get an exhaust for the room in addition to the one you're using for the hoods. See if you can improve on the intake of cool air. In my system I have a fan blowing hot air out of the chamber directly to the outside but the intake fan takes air from inside the room so temps stay below 28° during lights on.
- Thread starter
- #19
Aye i've seen the mini AC portable units around & had a quick look at a few models...
Now i don't have any experience with such but would question its total output of cooled air to the room size you are using it to whether it makes any difference !
Its a fine line to draw to be honest & i would not like to make a suggestion on that... inless other growers have greater experience on this particular matter ?
I'd still be tempted to look at air cooled hoods tho & mildly cheaper to set up
Providing all warm air is vented from room which the grow tent is situated in to prevent recirculation of warm air !
This is how i have it, connected on my hood pulling the air hot out..yes it is goin in the same room because now i have no way of takin it anywhere else lol, and like i said theres a fan on the bottom there (which you cant see but it is there) blowin air in, the temp in the room itself is always at 70-72F because ac in the room is always on. Now the temp under the lights i can maintain it at 82, 84F tops with the lights on when i have the tent open, now if i close it and just rely on the fans the temp will jump to 88F possibly 90F or more. And when i mentioned the small ac unit, i meant as in using it to blow cold air directly into the tent. Mount on the back or on the side or something, and just have the exaust fan blowing hot air out keepin the fresh airflow?
Some call a swamp cooler an A/C... a swamp cooler does like Rodrigo says, raises RH!
A compressor base A/C will cool the air much better and will lower the RH.
If you can find a used portable A/C that'll do the trick. I have 4 A/C units and 1 swamp cooler. 3 are window A/C units, 1 is portable and 1 is a portable swamp cooler.
The window A/C is cheap and very effective, but requires mounting in a window or thru a wall. A portable A/C will move around and only requires a 'dryer vent' to get rid of the hot air.
I run a 5000 BTU window unit full blast and it doesn't hold up very well. I'd suggest getting one of the 8000BTU units as they really don't cost much more.
You should be able to find used ones on CL or somewhere. I just bought a 24,000BTU monster unit for $150 from a local seller.
I got the portable one for $20 because the door was falling off, it still functions great.
Two points were made above by others.
1. temps only matter at the top of the plants, where are you measuring your temps?
2. most gauges suck. I have a RH meter that reads 10~15 higher than the other. Get a different brand, they can be found cheap. I have 4 of them and they all give different answers...
Your home A/C might have ducts that control air flow, see if you can up the air flow to the grow room.
A compressor base A/C will cool the air much better and will lower the RH.
If you can find a used portable A/C that'll do the trick. I have 4 A/C units and 1 swamp cooler. 3 are window A/C units, 1 is portable and 1 is a portable swamp cooler.
The window A/C is cheap and very effective, but requires mounting in a window or thru a wall. A portable A/C will move around and only requires a 'dryer vent' to get rid of the hot air.
I run a 5000 BTU window unit full blast and it doesn't hold up very well. I'd suggest getting one of the 8000BTU units as they really don't cost much more.
You should be able to find used ones on CL or somewhere. I just bought a 24,000BTU monster unit for $150 from a local seller.
I got the portable one for $20 because the door was falling off, it still functions great.
Two points were made above by others.
1. temps only matter at the top of the plants, where are you measuring your temps?
2. most gauges suck. I have a RH meter that reads 10~15 higher than the other. Get a different brand, they can be found cheap. I have 4 of them and they all give different answers...
Your home A/C might have ducts that control air flow, see if you can up the air flow to the grow room.
