DIY Window AC Box Build For a Tent

[Cannabean]

what are you doing about the water that leaks out the back of that ac? or does it not leak ? get a special AC?? my ac will leak if I tried that lol. since I only have a small 2000w grow right now.. I was thinking of adding a 1000w vertical inbetween my 2 1000s horizontal. but there is no window in the are of the grow. I was thinking of cutting a whole into the wall I built .. and putting the ac in the wall.. but then I was thinking. wat about all that EXTRA WATER coming out the back.. and shit.. if I seal my lights up I could probably do it .

hows it working out.. keeping your room cool?

hi EastCoast710. good question! depending on how often your AC turns on, you don't always have to do anything with the AC water discharge. in the winter, my AC runs maybe 5 times a day for less than a minute. any water created just evaporates as the days go by.
in the summer though, it may not evaporate enough for how often the AC runs. In the very bottom of the AC unit, I used a cordless drill to drill a tiny 1/16" hole in the metal at the bottommost part of where the water collects. i let it drip into a jug and dump it every few months.

 

[MsMileHigh]

Cool thread! Im in the procees of trying yo build a box for my ac

 

[tommyleebones]

Wow, thanks for your detailed and considered response!

You got the idea right, I was suggesting it look like the front half of your box. I thought about just doing the cold air part as you suggest, but worried that that would cut down on the dehumidifying aspect considerably, which is a real problem here in the swampland.

But either way I had a new idea: to build a transom in the doorway between Room 1 and the hallway (where the squiggly line is), and mount the AC above that, with a box for the warm air exhaust (like the back of your build). The doorway is about 9 feet tall, so there's plenty of room. That exhaust would have a diagonal duct to one of the two windows. I would leave the sides of the unit open for the motor cooling vents, of course.

This is advantageous for a few obvious reasons, but I think the best one is that there wouldn't be any ducts going vertically, which would have required a good fan to prevent backflow. Also the amount of work involved is much less (one box going over a rectangular area, vs two over some potentially curved/grated areas). Also I would have direct access to the AC from the room, instead of having to breach into the warm hallway every time I wanted to change the settings (though I'll be sure to get a unit with a remote, since it'll be so high up). Also, in my understanding, having the cool air pump in from higher up will help it circulate better (since it'll want to fall anyway). And we get our warm-air-out/cold-air-in circulation to boot!

Now my only concerns are:
• Draining the condensation, which I figure I'll do by designing the duct to tip slightly downward, and run some kind of extra sheeting inside with a crease in the middle, to act like a storm drain.
• Creating an efficient airflow for the duct. My initial thought is to have the duct run in a diagonal line from the doorway to the window, to avoid any of those draggy turns. Does this make sense? Based on your first post I still would need a fan in the box, I presume?
• Noise. The hallway isn't ever "hung out" in, so it being noisy isn't that huge of a deal. And I plan to put a door in below the transom (for insulation), which should help block the sound from permeating Room 1. And if it's still noisy, I'm prepared to live with that.

Also in my head I imagined the duct as a long, diagonal rectangle, so the output size would be the same dimensions as the input side (ie the height and width of the box). But I realized that would probably require cutting some sheet metal to spec, and would be more work than just building a box and attaching a 6" circular duct to it, as you did. Does that make sense too?

and yeah, I considered a portable AC for a bit... But most of them have a hose with a maximum length of 4-5 feet, whereas I would need probably 8. I looked into extending the hose but almost all manufacturers say that that will void the warranty, since it greatly increases the risk of burning out the fan. And also many of them said to not let the hose "dip" (ie drop to the ground then come back up), that it should only go across, and slightly vertical if need be. This would cause a real tripping problem with the hallway. I was also turned off by the units' generally shitty energy efficiency (especially with an extended hose), and greater cost. Plus having to drain the water manually... It all seemed like too many problems to deal with for paying so much for the unit.

I'm consulting with my construction-wizard friend tomorrow about all this, and hopefully will have everything put together by next week, unless I die from heat exhaustion first!

Thanks again for putting your brain on this! Would love to hear what you think about the new plan, especially in regards to the diagonal, turn-less duct. Cheers!

 

[EastCoast710]

we are doing the exact same thing.. our room was built inside of another room.. so in order to cool the room I either have to cool the lung room.. which isn't very efficient .. so im cutting a window size hole in the wall .. and putting my window ac directly into the wall and grow room.. ill put it about 2 feet off the ground.. so that I can put a tote underneath for condensation.. which ill just take my extra pump .. and have it setup like a toilet.. kinda.. were once it fills to a certain point the pump will turn on and get rid of the water..

last year.. I had put an ac in the window in the lung room.. and had issues with the lung room getting too cold.. and the grow rooms not getting cool enough . so I tried the ducting.. and by the time the air gets across the room. its not worth the electricity.. I tested using a AC.. VS running lights at night.. and having air from outside cool the room.. and it was the EXACT SAME TEMPS.. so I chucked the AC. used cool air.. now. im thinking if I can put the ac directly into the grow room wall.. it will cool the room and only the room.. before I had 3 rooms in the room its in.. now only 1 single room.. hoping it will be easier..


can anyone give me tips on how to keep my room cooled with an ac.. without losing all the AC.. im going to run a closed air cooled setup on my lights.. and another exhaust.. to get some clean air in there.. but im trying to figure out.. if its going to be defiecient in Co2.. ? or what? should I grab an Exhale bag for the summer run? or

I was even thinking of saying fuck it.. and grabbing a few exhale bags for the summer.. and use outside air to cool the room at night.. and run the room a lil warmer then id like but with Co2 ... would that be ok ?

ive been growing for a decent amount of time so I know how to grow fine.. but ive always just air cooled my lights.. and exhausted the air at the same time.. so im not really knowledgable on it....

and dude^^^.. u can extend a few feet.. if u add a 4 inch inline fan from homedepot.. this is how a friend of mine has been using his for 3 years.. hes got 2.. 1 that's not extended at all.. and the other that is.. with the fan on it.. the fan helps the air get threw the extention .. and that allows the other fan to not work nearly as hard.. he hasn't had a single problem.. he just had to make his own hoses insulation and shit.. he bought 8inch ducting.. put it over the 4 inch.. and used spray foam to fill the outside up .. worked like a champ..

 

[Cannabean]

But either way I had a new idea: to build a transom in the doorway between Room 1 and the hallway (where the squiggly line is), and mount the AC above that, with a box for the warm air exhaust (like the back of your build). The doorway is about 9 feet tall, so there's plenty of room. That exhaust would have a diagonal duct to one of the two windows. I would leave the sides of the unit open for the motor cooling vents, of course.

I had to google 'transom' haha I've never heard of that before. that would be more efficient I think. You would only need to deal with the motor exhaust air.

remember the condensation water collects in the bottom of the unit. if you're planning to make a transom connecting room 1 with the outside wall across the hallway and use some sort of bent sheet metal in the bottom to direct the condensation out of the box, it would probably work.

but after thinking about that, i thought...do you own this house? if you do, it might just be more efficient and cheaper in the long run to install a mini-split ac to the entire house and duct a vent into room 1. mini-splits are the most efficient ACs and most ideal for any situation but also need to be installed professionally, which growers dont want to risk doing. since you're not doing anything illegal, would this be an option?
.

• Creating an efficient airflow for the duct. My initial thought is to have the duct run in a diagonal line from the doorway to the window, to avoid any of those draggy turns. Does this make sense? Based on your first post I still would need a fan in the box, I presume?
• Noise. The hallway isn't ever "hung out" in, so it being noisy isn't that huge of a deal. And I plan to put a door in below the transom (for insulation), which should help block the sound from permeating Room 1. And if it's still noisy, I'm prepared to live with that.

it makes sense and yes you would need a fan in the box. exhaust fan motors on a typical 10k btu ac are around 250cfm and you'd need an exhaust fan which matches that speed.

the diagonal box makes sense and I think it would work fine with a complementary exhaust fan

Also in my head I imagined the duct as a long, diagonal rectangle, so the output size would be the same dimensions as the input side (ie the height and width of the box). But I realized that would probably require cutting some sheet metal to spec, and would be more work than just building a box and attaching a 6" circular duct to it, as you did. Does that make sense too?

I'm consulting with my construction-wizard friend tomorrow about all this, and hopefully will have everything put together by next week, unless I die from heat exhaustion first!

Thanks again for putting your brain on this! Would love to hear what you think about the new plan, especially in regards to the diagonal, turn-less duct. Cheers!

you'd definitely need to come up with something to deal with the condensation. sheet metal would probably work the way you describe. make sure you use enough metal to make 'walls' to the funneled drain, just in case. seems sketchy though but I cant think of any better ways. you could make the box larger and drill a hole in the bottom of the ac housing and direct all water to a single tube that drained to the outside...that would be more difficult than sheet metal idea.

if you built a box and ran inline fan with ducting exactly like I did, you'd still have to deal with the condensation so I'm not sure you have that option with the way you'll need to mount the AC. i think you're onto something with the transom lol but it wont be easy. keep thinking through it we're close

 

[Cannabean]

can anyone give me tips on how to keep my room cooled with an ac.. without losing all the AC.. im going to run a closed air cooled setup on my lights.. and another exhaust.. to get some clean air in there.. but im trying to figure out.. if its going to be defiecient in Co2.. ? or what? should I grab an Exhale bag for the summer run? or

I know what you mean with the AC cooling off the lung room but the grow room staying too hot. sounds like you're almost there. keep the AC mounted in the window or whatever you have it mounted from the lung room to the outside. build a box over just the front of the AC exactly like I made. yours will be much more efficient than mine because you can run straight ducts from the intake and cold air exhaust ports on the front of the unit directly into the grow room.

so the AC sits in the wall between outside and the lung room. condensation drips out the back like its designed to do in a window. you have a box built around the front with directing two ducts into the grow room. put the home depot inline booster fan in the helping push the cold air exhaust into the room. use a nice large diameter duct for the grow room intake air, and no fan needed. it'll work better and more efficient than the box i had to build. combine it with a cap art-dne timer mounted inside the grow room and you've got a controlled environment. or go fully legit and combine your CO2 system with your day/night temp controlled AC via a cap air-3dn. you're very close to have a perfect sealed environment.

 

[Bueno Time]

Nice tutorial and great idea to save money vs a portable ac.

 

[wrinkles88]

I just noticed this now. I will be subscribing to this!

 

[gram101]

i have a 880 watt led light inside a 4x4 tent.
i'm considering putting the window a/c inside a hole cut out of the tent.
my question is it necessary to duct the heat exhaust of the a/c out of the bedroom?
could i just allow the hot air to accumulate in the bedroom? possibly crack open a window?

my ambient temperatures are about 80-84, with lights during the day it gets up to 91.

 

[Cannabean]

the ambient air room needs to separate from the hot air exhaust unless sitting in a window where they share the outside air. if they shared a room, even with an open window, it would get so hot in there it would defeat the purpose of your ac.

if you have the tent in a room with a window, can you slide the tent up flush with the window and mount the AC in the window like it's meant to be and cut the hole in your tent for the front?

 

[gram101]

I can. You dont think that makes it more susceptible to smell getting out? I hear the LG units have slits where you can limit the air that leaves the room. I have a 550 cfm filter on exhaust from the tent. I plan on running 5 to 10 plants. I have more fans i can use for more filters. Would i be okay?

 

[Scottish Research]

This is a neat thread. I'm interested in this method for a mini split.

 

[Cannabean]

I can. You dont think that makes it more susceptible to smell getting out? I hear the LG units have slits where you can limit the air that leaves the room. I have a 550 cfm filter on exhaust from the tent. I plan on running 5 to 10 plants. I have more fans i can use for more filters. Would i be okay?

do you have the 550cfm fan pulling air out of the room? if so, how does your AC even keep the tent cool? seems like the fan would pull the cold air out before it could cool down the space. i may be confused because you said exhaust.

usually ACs are for sealed environments where you're 'scrubbing' the air, recirculating it inside the tent. in this setup, you'd have a dedicated duct line and fan for keeping the light cool.

what I'm trying to say is if you have a sealed environment, using a window AC this way would not cause smell to leak. that's the beauty of window ACs...the motor exhaust and intake is separate from the cold air intake and exhaust, so no smell leaks out.

i can explain a sealed room in more detail if you have questions. it has many benefits over a non-sealed room

 

[gram101]

the 550 cfm exhaust fan is to pull the hot air out of the tent. are you saying i don't need to have a fan to remove the hot air from the tent? i have a ducting that connects to the top of the tent and the fan pulls the hot air through to a carbon filter on the outside.

thank you for your responses.
i appreciate it!

 

[tommyleebones]

Hello again! This is the guy who was trying to cool his bedroom in the oddly built house...

So, after much deliberating, planning, replanning, etc... I figured out a completely different set-up. So in the room, Room 1, there was a unique feature: a radiator set into the floor. As in, there had been a rectangle cut out of the floor, and a radiator inside a metal was dropped through it, attached at the top, with a grate over it. I figure this was a method of heating the room after fireplaces were banned in this neighborhood. But based on the level of dust, rust, and general design, the unit had been defunct for decades.

So I realized that if I took the radiator out, I would have a hole to under the house (buildings here are lofted a few feet, with no basements). And this would be an ideal exhaust situation for a portable AC...

So that's what I did. I made a plywood board a little bigger than the hole in the floor, cut a 6" hole in that board, then attached some ducting to the bottom of the board to route the airflow away from under my room (because I figure having all the exhaust heat expel right under the room would just mean it would seep up through the uninsulated floorboards). As part of that ducting I added in an inline fan (with a slightly higher CFM than the AC), thanks to the knowledge you provided on here, Cannabean.

Then I just plopped the AC on top of the board and plugged its proprietary exhaust tube into the board's hole and voila! It's cool as a cucumber in here.

The best part of the design is when summer's over, I can just unplug the AC exhaust tube from the board and plug up the hole, so there's not a stupid AC unit sitting in the middle of my two rooms.

Anyway, just wanted to update ya! Sorry I didn't use any of the build ideas that this thread was started for... but who knows, maybe this'll fail soon and I'll need to try it eventually!

Thanks again, and be well!

 

[Cannabean]

the 550 cfm exhaust fan is to pull the hot air out of the tent. are you saying i don't need to have a fan to remove the hot air from the tent? i have a ducting that connects to the top of the tent and the fan pulls the hot air through to a carbon filter on the outside.

thank you for your responses.
i appreciate it!

you have a few options here. adding an ac to your current setup would probably not be efficient becuase you're pulling 550cfm of air out of a 128cf tent.

but if the ambient temps the fan is pulling from are too high, you'll need to ad an AC. but you'll have to change your setup for the better to do this. you're still going to use your 550 cfm fan, just for a different purpose.

slide the tent next to the window and cut a perfectly sized hole in the tent for the face of the AC. set up your fan so it sits outside of your tent and pulls air through a duct connected to the light and out the other side of the tent so air is not pulled out of the tent.

tent wall |
duct ==
light ()
airflow >>>
>>>|==()==|=fan>>>==outside

ideally your fan will pull air from the room your tent resides in, through the duct connected to the light, out the other side of the tent and then ducted outside. this is a sealed environment.

no air moves in or out of your tent. since plants use co2, in a sealed environment you will have to supplement co2. you'll need to get a 20lb co2 tank, a co2 regulator (this), and some air hose to disperse the co2. it'll cost about $200 for a tank full of air, a regulator and hose.

this allows you to not only supplement co2 but pump extra co2 into the environment which is significantly beneficial to growth and yield. it also allows you to run temps 3-5deg higher than is recommended for a regulator environment which saves on energy. i ran mine 82deg day/76deg night. your ac will be amazingly efficient in a 4x4 tent.

there are many informative threads on icmag if you want to learn about sealed environment and co2.

 

[Cannabean]

Hello again! This is the guy who was trying to cool his bedroom in the oddly built house...

hi teommyleebones. what an interesting house and neighborhood you live in.

sounds like you found a good solution with a portable ac. good idea to add the fan but because portables work differently than window ACs, you'll want to check some things to ensure its efficient.

after the ac has been running for a few minutes, check the temperature of the air being pushed out by the inline fan you added. it should be hot probably 100-120 deg. if it is cool or lukewarm, your inline fan may be pulling so much air that some cold air is being sucked out.

how far are you ducting the exhaust air? if it's a long distance, a fan is recommended. if its the default length of the portable AC hose kit, you probably don't need an extra fan. i'd just hate for you to be inefficiently exhausting cold air from my advice. good luck

 

[gram101]

thanks for your reply Cannabean but it's not a HPS or air cooled light.
Its a LED light so the ducting can't go through the light.

i could still do that setup but it would just be pulling the a/c'd air out of the tent.
i think that's basically my only option though.

either cut a hole through the tent and have better efficiency on the a/c
or, i can just let the a/c sit in the window seal and condition the whole room but that's more inefficient.

i was considering building an a/c box but that's a lot of work..
and then i'd have to cut holes in the wall which isn't pleasant but at least it would be no visible sign of a grow..

 

[Cannabean]

i don't know how hot led lights get but you may be able to run a sealed room with only the ac providing cooling. same setup except no air cooling for any lights.

 

[SMOKE-ONE]

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