# Window AC converion for an enclosed space



## monkeybusiness

Well since i had to convert a window AC unit to use inside an enclosed area, i figured I'd try to document the process since there seems to be quite a few misunderstandings about the concept.
Now I'm going to explain the theory/concept and then show how i decided to convert mine but it's going to be one of those, 'do as i say, not as i do' demonstrations. Frankly, i don't recommend you do it exactly as i did because i was battling space and supply factors. Basically i wanted to use supplies i already had and I had to install it into a very confined space so I made a pretty tight conversion. I'm comfortable with that because i have a dedicated exhaust fan with plenty of CFM's to make sure heat is sucked out of condenser. You'll have to decide whats best for you.

Anyways... 
on to the show:

As you can see in the pictures, an ordinary window AC unit with vents on the back, sides, and top. The air is suppose to flow *in through the sides and top* and *out the back*. This is the most important thing. (I've seen where people just put the ac in a room and blow a fan across the back and that won't work. It might seem to work for a while but even if it does bring the temps down it will shorten life of your AC)
 So, you will have to figure out a way to funnel air in, then out the back. I've seen where people build a box to enclose the top and sides and funnel it into an intake hose, as well as building a box on the back to funnel out to an exhaust hose. I'm going to close off the sides completely and funnel fresh air thru the top and out the back.


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## monkeybusiness

So i have a big ole vent connector that will work great. I just set it on top and make sure everything lines up ok. Once i have it where i want it, I trace the inside with a marker so i know where the opening sits compared to the inside.


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## monkeybusiness

Then i pull the cover off to see where the hole lines up (don't want to just cut the entire outlined rectangle open before making sure there aren't any conflicting items. And as you can see, there are conflicting areas) 
 We don't want to cut it all open and pump are into the front and the back. We just need to open up where the compressor is and the other thin channel through the middle. The thin channel already has the vent over it so i only cut open an area over the compressor.
 Now while it's open, double check your game plan to make sure no screws are going to puncture anything or stuff like that, etc. (I strongly recommend you screw from the inside to the outside to avoid accidentally puncturing something important)


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## monkeybusiness

Then i encased the back with a face frame made out of 2x2's and the top with 1x2's (screwing from the inside out and trimming/sculpting wood as nessasary) You will also see that i used some cheap sheet metal to cover the sides


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## monkeybusiness

Then i screwed the vent connector on top and put on a piece of sheet metal that covered the back entirely. After i cut an access hole in the back i install the hose connector and that's basically it. ( I apologize, i was pretty stoned at this point and completely spaced taking pics of this step)
I would have normally built the back out more for extra breathing space but then it wouldn't have fit in my particular area.

I have passive fresh air going in the top, and the exhaust fan sucking hot air out the back.  Been up and running a few weeks now and seems to work like a charm.

Hope this helps!


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## monkeybusiness

Oh i forgot to note, you'll have to drill a hole for condensation drainage. I drilled a small hole in the plastic case (under the condenser (back area of unit)) and connected a 1/4 inch hose to drain it to a container.


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## notpatient

that is an awesome Idea, I built a box for mine and cut a few holes and worked fine too


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## hanfhead

Looks good!!! I just had to spend 3 bills when it got warm outside for a portable a/c.  I was going to try this (I have 3 window a/c units) but wasn't quite sure where to start. 

That looks like it would fix any smell problems, drawing fresh air to cool the coil. The portable unit just uses the air in the room and blows it over the coils and out an exhaust.  I need to build something like that for an intake on my portable unit and take air from somewhere else.


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## zipflip

i dig it as well. only im thinkin something like your obviously gonna have to have some sort ducting gettin the hot air outside, so im wondering if it'd be any difference running ducting from an ac thats just in a window blowing cold air in and havin an inline exhaust close to the grow room/box blowin it into it  vs doin all that and ventin the hot air from the ac outside.  either way ya gonna have some duct work from point A to point B outside... 
 also if ya had somethin expelling hot air directly from the ac which is rather warm constant, imo would raise more suspicion than just installin a normal ac as ya would in a window and just have it rigged wit the duct thiigs ya added  but for the cold air 
  but i know sometimes there circumstances that change the whole deal which may be in your case as to why ya did it this way. 
 good build tho


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## monkeybusiness

zipflip said:
			
		

> i dig it as well. only im thinkin something like your obviously gonna have to have some sort ducting gettin the hot air outside, so im wondering if it'd be any difference running ducting from an ac thats just in a window blowing cold air in and havin an inline exhaust close to the grow room/box blowin it into it  vs doin all that and ventin the hot air from the ac outside.  either way ya gonna have some duct work from point A to point B outside...
> also if ya had somethin expelling hot air directly from the ac which is rather warm constant, imo would raise more suspicion than just installin a normal ac as ya would in a window and just have it rigged wit the duct thiigs ya added  but for the cold air
> but i know sometimes there circumstances that change the whole deal which may be in your case as to why ya did it this way.
> good build tho



I thought about just ducting the cold air in but it wasn't a manageable task for my particular setup. 

 I actually mounted it by cutting a hole in the wall of grow room so the good end of the unit sits inside the grow room and the hot end is on other side of wall. Works great and doesnt take too much space away from room. I would imagine if someone was worried about people noticing the hot air you could just install a dryer vent on the outside of building and pump it through there as if it were just a dryer running inside. just a thot...


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## 4u2sm0ke

nice idea..with the unit outside the box  how does the ac temp controler work?  very good layout..im sure it will be a sticky b4 long..thanks for shareing with us my friend..take care and be safe


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## monkeybusiness

4u2sm0ke said:
			
		

> nice idea..with the unit outside the box  how does the ac temp controler work?  very good layout..im sure it will be a sticky b4 long..thanks for shareing with us my friend..take care and be safe


 Well the front end of the unit, with the controls, sticks in the room enough that it was just a matter of dialing it in on the controls till i found a temp i liked. I'll snap a pic later but its just the front end sticking through the wall. (Which was another reason i decided to do it this way instead of trying to vent the cold air in. I wanted to be able to use the built in thermostat and controls)

 I should have said in my original post about how it was mounted with the warm side outside the growspace but i always seem to lose my train of thought at the worst moments. Not really sure why that is... hmm, where's my bowl.... what's 4 breakfast... who was that... what was i sayin.. oh yeah


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## 4u2sm0ke

okay  thanks..another  thing  is  like what  Zip  asked  and why break the unit down?  why not just intall as usual?  what is the bennefit  other then  a smaller whole?  i  still like it  just  seems like we coulda just  cut  a square hole?  but  I will fallow and see you  final outcome..thanks:bong:


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## monkeybusiness

4u2sm0ke said:
			
		

> okay  thanks..another  thing  is  like what  Zip  asked  and why break the unit down?  why not just intall as usual?  what is the bennefit  other then  a smaller whole?  i  still like it  just  seems like we coulda just  cut  a square hole?  but  I will fallow and see you  final outcome..thanks:bong:


 Well in this room there are no windows or exterior walls and even though it's kind of near an exterior wall, the exterior walls in this building are a very, very old, super thick, southwestern walls that would be pretty unwise to cut a hole this large in. And if i had tried to mount it in exterior wall the controls wouldn't have been inside the grow area either. It was a slew of hurdles i didn't want to have to deal with but once i got my mind set, there was no turning back!


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## monkeybusiness

I should also point out that i recently did one with a buddy and we built more of a box off the back and used insulated flexible ducting on the exhaust so he could just set it right inside the room. He hasn't had any issues other than it takes up a stupid amount of space, in my opinion..


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## monkeybusiness

just a quick update to note that this has been up and running most of the hot season here and is working great! Temps stay within a degree or 2 at all times and our outdoor temps have been hitting 100 lately.

 My buddy who also has a conversion we did, but has it on shelf inside his grow room, is also having same results.


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## DenseBuds

Hey there... fantastic tutorial, thanks! I'm looking to build basically the same setup you have here. I had been considering building a box around the unit, but as you pointed out it seemed like it would turn a big unit into a huge unit. Your method seems ideal.

A couple of questions if you don't mind:

I smoke in the room where I have my grow tents/cabinet in. Because of this, I will want to hook the exhaust to the window as well as the passive intake. My hope is to prevent any smell from passing through the A/C to the outside. Based on the design of window units, it seems this shoud be possible?
What size round ducts do you think I need to use both for the exhaust and the passive intake? If possible, I'd like to use 4". The room is roughly 13'x13'. I was thinking of going overkill and getting a 10k btu unit?
Can you take a picture of the drainage? Without modification I take it that the water just falls off the parts inside the A/C and drips off the unit at the lowest point? Do you angle your unit a specific way so it funnels to your drainage tube?
I didn't read that you needed any additional fans for the exhaust or intake after the conversion. Is that right? My unit will be sitting just inside the window so its not like there'd be a huge amount of ducting anyway. I am doing this because if I build my own window panel for the intake/exhaust and I go on vacation I can just take down the panel easily and not have to unmount/remount the entire unit in the window. I shut off my HIDs while I'm away anyway so the temp remains cool.
It gets REALLY hot here in the summer. Talking 100+ for most of the summer. It seems that this might be a problem when you're using outdoor air to cool the unit? Or does it not matter? I imagine if that were the case, they wouldn't be able to sell window A/C units in extremely hot climates.


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## monkeybusiness

DenseBuds said:
			
		

> Hey there... fantastic tutorial, thanks! I'm looking to build basically the same setup you have here. I had been considering building a box around the unit, but as you pointed out it seemed like it would turn a big unit into a huge unit. Your method seems ideal.



Thanks for the kind words!



> A couple of questions if you don't mind:
> I smoke in the room where I have my grow tents/cabinet in. Because of this, I will want to hook the exhaust to the window as well as the passive intake. My hope is to prevent any smell from passing through the A/C to the outside. Based on the design of window units, it seems this shoud be possible?


Sorry man, I'm not sure i understand the question. But the window a/c takes the air from inside and cools it (technically it removes heat i believe) and puts it back into the room. The venting of the back of the unit is seperate from what goes on inside the room. However i have read that if a window unit is installed in a window of a grow room that some smell can escape, even still.


> What size round ducts do you think I need to use both for the exhaust and the passive intake? If possible, I'd like to use 4". The room is roughly 13'x13'. I was thinking of going overkill and getting a 10k btu unit?



 Well if you plan on ducting the heat out of the back of the unit i doubt 4" would do a good enough job. Especially if you going to have a tight back end like this one(instead of a box). The heat needs to be sucked out. I'm going to upgrade my a/c this year to a bigger size. Even though the a/c i am using is designed for a room much bigger, it's not designed for a room producing the kind of heat i was/am. So i would take 'their' room size recommendations with a grain of salt because they aren't factoring in a 'heat producing' room.



> Can you take a picture of the drainage? Without modification I take it that the water just falls off the parts inside the A/C and drips off the unit at the lowest point? Do you angle your unit a specific way so it funnels to your drainage tube?


I can't right now. It's in an ackward part of the building and way too tight to get back there. But yep, i just shimmed up the appropriate side so that all water ran to the side i have the drainage hole/hose.


> I didn't read that you needed any additional fans for the exhaust or intake after the conversion. Is that right? My unit will be sitting just inside the window so its not like there'd be a huge amount of ducting anyway. I am doing this because if I build my own window panel for the intake/exhaust and I go on vacation I can just take down the panel easily and not have to unmount/remount the entire unit in the window. I shut off my HIDs while I'm away anyway so the temp remains cool.


I use a 6 inch fan to pull the heat out and use passive intake. Not sure what you'll be able to get away with, depending on how close it is to the window, but the second you close the back up with panels you're insuring that it will get HOT back there. I also recommend insulated ducting and, if you can, insulate the back end so the heat doesn't leak back into your grow room. 


> It gets REALLY hot here in the summer. Talking 100+ for most of the summer. It seems that this might be a problem when you're using outdoor air to cool the unit? Or does it not matter? I imagine if that were the case, they wouldn't be able to sell window A/C units in extremely hot climates.


  It gets hot here too but i didn't have any problems this past year. Hope it helps. Let me know if you have any more questions..


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## DenseBuds

This helps a lot, thanks!


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## DonJones

Puff,

Great job. 

The reason some smell can leak through the window style AC units is because they are NOT sealed real well between the two sets of coils an a little air does leak both ways past the seals.

Great smoking.


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## DenseBuds

DonJones said:
			
		

> Puff,
> 
> Great job.
> 
> The reason some smell can leak through the window style AC units is because they are NOT sealed real well between the two sets of coils an a little air does leak both ways past the seals.
> 
> Great smoking.



Thanks for the info. Do you think I could enhance the seal somehow? For purposes of limiting smell, do you think the window units are still better than the single or dual hose portables?


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## LEFTHAND

*I like it MB... had a simliar idea to do the same...
LH*


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## DonJones

DenseBuds,

You probably can enhance the seal, but I think I'd try it the way it comes first and if it isn't a problem leave it alone but if it gives you problems, then start enhancing the seal.  Also not all window AC units have the same quality of sealing between the two sides. Remember, a slight cold to hot air leak isn't a problem like a slight leak of strong odor filled air might be, so what is a good seal for their purposes may not be any where near good for your purpose.  However, the leakage should be fairly minor.

Also if you are venting both intake and exhaust air through the same window, try to keep the hot exhaust air as high and far from the cool intake air as possible.  You don't want to be pulling the hot exhaust air right back into the AC or your efficiency will go way down.

You would be surprised how much difference in the effectiveness of the unit can be improved some times just by creating shade for the unit rather than direct sunlight.

Great smoking.


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## DenseBuds

Thanks. I will run a test the first night and go outside while my wife is smoking and see what I can smell with the A/C running. I'm going to have the exhaust mounted above the intake in the window for sure, but I don't know how far apart. Need to see how much air comes out the exhaust. Think it'd look weird to have one at the bottom and one at the top in the window.


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## matt612346

nice work looks good


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## DonJones

Anyway you run vents through a window is going to look weird unless you put fans in them.


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## monkeybusiness

DonJones said:
			
		

> Anyway you run vents through a window is going to look weird unless you put fans in them.


Well if you have aircooled lights then you've already figured out where to vent the exhaust. Intake can come from anywhere. The cooler the better though. I myself pull fresh air from outside. 

Where there's a will, there's a way!


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