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calif123

Air conditioning

16 posts in this topic

Hi,

I was wondering if anyone here has any examples of the effect of using a portable AC unit within a smallish (3mx3m) room, on grow tent temperature? With the current heat, I am struggling getting the temps down in the tent even when using the T5 prorogation light. 

 

I know the BTUs required will depend on many factors, but I am not sure how many BTU's I would need for that space, and thought some indicative examples from the community may help with my guess.

Cheers

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Posted (edited)

hi welcome to the site. ac units cost allot to run, and buy. your better off inproving air flow in the tent, getting a bigger extraction fan than needed and having it on a speed controller to run it at like 40% power, if your using a 3m x 3m room then you need a 8 inch high power rvk fan, on a voltage stepping controller. with a 6 inch inlet allso on a controller, that would give you plenty of air out, and air in, to run hps lights in the summer, with temps of 28c max. i run the same size room there about in a spare bedroom, and use a 8 inch high power rvk on a v/tage stepping controller, with a 6 inch air inlet, using 3 x 600w hps lights/ soon to be swoped for 3 x 315w cmh lights, and just the one 600w hps to get a full spectrum light for the girls. 

the money you would spend on a good ac unit that mount onto walls you could get the above set up of fans/ fan controllers. and you would have the perfect grow inviroment, plants take off with vigorous growth when you have loads of air going out, plus a good air inlet of fresh air at about 50 % less than your outlet air, keeping the negative pressure to stop any smell leaks and make sure your carbon filter does its job properly. 

all the best with it. :skin_up:

Edited by smokie1 b c f c
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Posted (edited)

using t5 cfl lights you shouldn't be getting high temps ? are you extracting your hot used air from your extraction fan strait outside via a vent on the wall,or a open top slit window ? 

if you kick the used hot air out at a high enough rate, then have your fresh air inlet fan drawing in cool air from in the house, or from under the floor boards if its vented, if your extracting air out enough then having the bedroom door with a slim vent at the bottom can be enough to have your air inlet fan pulling air in from behind the door, so it can be kept closed/ locked. :yinyang:

Edited by smokie1 b c f c

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Used to run air-con in groom about 3m x 2.5m before I was in a tent means an extra heat exhaust that needs to be filtered mine was 9000 btu I can say that it worked but down sides are extra noise and extra electric costs not cheap to run permanently they are bulky to put in a tent but you could put it in the room the tent is in and modify it so the cooled air is then ducted into the tents intake what size extraction and flow rate you using? And when are you running your day lite hours?I’d first look at upping that before anything else Even if you’re running a few degrees to hot as long as they have good airflow they will still grow and you should still have a crop that is as good if not better than anything that’s around via dealers and will be a darn site Cheaper try and find your feet growing a few plants before spending loads of cash we can get hung up chasing the perfect environment especially if new to growing 

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i used to struggle with temps , the best thing i did was get a big fan on a speed controller as i said above, the plants grow them self's so well with loads of airflow, and air exchange. its the way of getting the best indoor grow enviroment for sure. my yield doubled at least too with proper air exchange :yinyang:

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Posted (edited)

@smokie1 b c f c 

At the moment, I have a 1.2m tent within the room, 6 inch (470m3) extraction through a CF, and a small 4inch intake fan(200 ish m3) drawing fresh air from an external loft vent (poor fan, its via a 10-15m duct). I keep one of the windows in the tent open to avoid too much negative pressure. The extraction is exhausted out an open window in the bedroom via a make shift box that converts the circle into a rectangle which I tape down just below the window frame for discretion.

 

I cannot feel that any exhausted air gets back into the room, but its not air tight by any means. The ambient temp in the room is around 23 before starting up anything, and goes up to about 25-26. 

The T5 does generate some heat. Maybe I don't have enough extraction, but I think I did my research and apparently 6 inch is good for 1.2x1.2, so I'm not sure where I'm going wrong. 

 

The only thing that came to mind is to shut the window in the room the grow tent is in and redirect the exhaust to adjacent bedroom (no spare vents in attic) and out through that bedrooms window. Then I was thinking of putting AC in the grow tent room to cool the environment that the grow tent is in.  Desperate times and all...spent so much already, that its getting to be a case of all or nothing....

Cheers

Edited by calif123

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31 minutes ago, Jim Herbert said:

Used to run air-con in groom about 3m x 2.5m before I was in a tent means an extra heat exhaust that needs to be filtered mine was 9000 btu I can say that it worked but down sides are extra noise and extra electric costs not cheap to run permanently they are bulky to put in a tent but you could put it in the room the tent is in and modify it so the cooled air is then ducted into the tents intake what size extraction and flow rate you using? And when are you running your day lite hours?I’d first look at upping that before anything else Even if you’re running a few degrees to hot as long as they have good airflow they will still grow and you should still have a crop that is as good if not better than anything that’s around via dealers and will be a darn site Cheaper try and find your feet growing a few plants before spending loads of cash we can get hung up chasing the perfect environment especially if new to growing 

 

Thanks for your example. Do you currently run a tent in an AC room? I have a 1.2m tent in the room. The extraction is a 470m3 (through an slightly open window) and intake 270m3 + openings in the tent to avoid the tent sucking in too much. At the moment, I'm doing daytime temp runs trying to get a stable environment. Figure its best to do worst case conditions, so when growing I don't have to fight both the plants and the environment. Would ducting the output of an AC into the tent play havoc with the humidity? I was hoping that maybe if I seal up the room (and stick an AC in there) the tent would be cooled passively, but I have no idea yet :) 

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@calif123 I noticed you say you’re bringing the intake air in from the loft as heat rises the hottest trapped air with in your house is going to be in the loft try pulling the air in from elsewhere 

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2 minutes ago, Jim Herbert said:

@calif123 I noticed you say you’re bringing the intake air in from the loft as heat rises the hottest trapped air with in your house is going to be in the loft try pulling the air in from elsewhere 

 

Sorry I wasn't too clear, the vent is on the side of the house, i'm just ducting it through the loft and into the room. I was going to just use the loft air, but as you say it is too hot and stuffy :) 

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@calif123 I’m not using air con now haven’t done for a few years im currently running a 6inch rvk exhaust I can’t remember the flow rate off hand with passive intake ducted from a window I have as I said I have option of running air cooled light but so far haven’t switched it on 27.3 degrees max temp yesterday running lights on 7am till 7 pm 

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mmm, as you say using a 6inch in a 1.2 tent. im using a 1.2 tent here with a 5inch ruck 2 speed fan, max of 360 square meters per hour, max temps are 30c i use 2 lenths of passive ducting going into each side of my tent. 

i think that bringing your air in through the loft is heating it up maybe ? try bringing in fresh air from the house, via the door proped open to the room, or a vent strip under the door, or a big vent cut into the door if poss. 

i know that when a fan is connected to the filter it looses some of its power, so your probly getting about 350 square meters per hour on full power ? have you got the fan clipped onto the filter in the tent, like rite next to each other i mean dude, without any ducting in between the fan and filter ? 

if not, then its time for a rethink on your air inlet design, and outlet. :yinyang:

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1 hour ago, calif123 said:

Hi,

I was wondering if anyone here has any examples of the effect of using a portable AC unit within a smallish (3mx3m) room, on grow tent temperature? With the current heat, I am struggling getting the temps down in the tent even when using the T5 prorogation light. 

 

I know the BTUs required will depend on many factors, but I am not sure how many BTU's I would need for that space, and thought some indicative examples from the community may help with my guess.

Cheers

are you running your lights on times through the nite bro ? i know that running them say 8pm to 8am in flower will give you lower lights on temps by a few c easy so if its say 32c now running lights on a day, then you should be able to get it at max 28c lights on running them at night time when the outside air is cooler. 

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5 minutes ago, smokie1 b c f c said:

mmm, as you say using a 6inch in a 1.2 tent. im using a 1.2 tent here with a 5inch ruck 2 speed fan, max of 360 square meters per hour, max temps are 30c i use 2 lenths of passive ducting going into each side of my tent. 

i think that bringing your air in through the loft is heating it up maybe ? try bringing in fresh air from the house, via the door proped open to the room, or a vent strip under the door, or a big vent cut into the door if poss. 

i know that when a fan is connected to the filter it looses some of its power, so your probly getting about 350 square meters per hour on full power ? have you got the fan clipped onto the filter in the tent, like rite next to each other i mean dude, without any ducting in between the fan and filter ? 

if not, then its time for a rethink on your air inlet design, and outlet. :yinyang:

 

I really thought that after getting an intake fan it would be enough but alas, the intake air is not too cool. Then again the air outside isn't either :) I've got the passive intake next to the door, which has a good gap to allow air to come in. The fan is clipped directly onto the filter, as you say to minimize loss. Will try intaking from another room to see if there is any difference. I suppose if I intake from the room, then come winter time I can regulate the intake temp better also. Cheers for the ideas!

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11 minutes ago, smokie1 b c f c said:

are you running your lights on times through the nite bro ? i know that running them say 8pm to 8am in flower will give you lower lights on temps by a few c easy so if its say 32c now running lights on a day, then you should be able to get it at max 28c lights on running them at night time when the outside air is cooler. 

 

Nope, not yet. I am doing daytime runs to see what the temp behavior is, then decide day or night. Looking like night right now! :) Cheers!

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7 minutes ago, calif123 said:

 

Nope, not yet. I am doing daytime runs to see what the temp behavior is, then decide day or night. Looking like night right now! :) Cheers!

 Run at night sprout some beans and get a grow or two under your belt when I downsized from a room to a tent it took me a while to dial in the environment again the first few crops went as good as I would have liked my first was winter with like 15 degree days and less tan 10 degrees at night but still ended up with enough bud to keep me going like I say it easy to get hung up chasing the perfect environment from the start to make up for lack of experience ect and rightly so as it’s a big investment of time money and risks  within a grow or too you will have learned a lot about your plants and environment and will have saved on cash by not buying from dealers Buy this time next year you will have experienced the summer and winter environments and will have saved enough money to adapt Rome wasn’t built in a day and all that 

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