AC Boxes Made Easy (to understand and build)

[hoosierdaddy]

Most of the small models of AC, like 5000btu, do not provide for condensate drain. They rely on evaporation to rid the unit of what water it might build up. It is all relative humidity specific, but I have never seen my 5050btu overflow of water. Since I have extra air flow from what it normally does, it is even better.

Sounds like you will be fine draining to a can or something.
The water will be collecting on the front side of the hot coils (where your cool air goes in), so you won't lose anything at all by adding a drain hose. That part of the unit is already open to the lung room.

 

[nekoloving]

hey awesome thread! this needs to be stickied bad; i spent a good while looking for it...

 

[OgreSeeker]

Ok HD here's the deal...

I was schooled tonight by an HVAC guy who explain what you have already stated about separating the air flow. What size fan would you suggest for a 24,500 btu unit. I'll have my ambient air coming in from a 12" duct but I'm not sure how many CFM would be required to move the air up and out.

Thanks man.

 

[Dr420CloneX]

excellent diagram and hands down air conditioners for dummies. easy to follow. I am now ready I think to set one up. Wasnt sure how I was going to do it but im thinking this has got to be one of the best ways to do it. thnx for the thread.

 

[smurfin'herb]

great tutorial

 

[Marick23]

Hey Hoosier excellent thread man.


I have a similar if not the same ac unit.. I my flower room would stay cool but the ac would have to work harder. Get hotter and then work harder until you couldn't go upstair during the day it was 110 120 easy up there. I didn't have a box and didn't see this thread. I had only the cool air portion in the grow room. panda plastic wall barrier the rest out side. I searched a bit but couldn't find anything. So I pondered for a bit... I am not a tinker. Nor am I very mechanically inclined. But it was obvious I had to get that hot air out of THAT room. Keep my cool air in the flower room and keep the second story of my house melting into a single story.

What I ended up doing was putting a 6 inch hole in my wall. Wrapped a black heavy duty trash bag over the outtake and pushed the other end in the wall cut a hole tapped it to the walll. Wallah! Haven't had a problem since.. the ambient air in the room is now a nice 80 degrees. Which makes it plenty cool. I will build a "proper" box for it 0nce I harvest. (broke) Hope this isn't considered highjacking I just thought I'd share a quick fix if your having this problem and can't build a box just yet...

Once again thanks for the Thread Hoosier!

 

[hoosierdaddy]

nekoloving, If you ever need the thread again, just search for my handle. I keep it in my sig line. Good Luck!

Dr420cloneX, I am glad this helped you. If you need any further help, don't hesitate to holler.

Thanks much, smurfin!

Maverick, yeah I can relate to broke as a joke. Hope your system holds up until some funds arrive!

OgreSeeker,
OK, you have 12" duct in, which should be sufficient in flow. You could stay with the 12" exhaust out. BUT...it may be a bit restrictive on the exhaust side, and the internal unit fan may not be enough to pull/push the proper air flow. So, what you need is a boost of sorts for that fan, rather than a single fan to pull all the air by itself. We already know that the fan in the unit is sufficient if there is no ducting out the back, and if you take the unit apart you will see that the fan for the exhaust is probably encased by some plastic. This is a duct of sorts, and the bottleneck of the AC. As long as you can keep the duct at least the same size of the fan enclosure, and no big restrictions (turns, flex duct, etc...) then the fan would probably do the job, BUT more than likely it needs a bit of help if you add any exhaust ducting that is smaller than the back of the unit.
And since we are talking about helping the ac fan, rather than doing the whole deal with an aftermarket fan, you would probably be close to sufficient with just a 6" fan pushing/pulling 250+ cfm. But that is just a guesstimation.
I would just about bet you would be golden if you used 8" duct for exhaust and a 8" fan of any sort.
One thing you could do to test things a bit, would be to run the unit, and while it is running add the exhaust duct to the back. Listen to see if there is any increase in AC fan rpm. This would indicate that your exhaust is restrictive enough to make the ac fan labor. If adding the duct makes no change in the fan speed or sound, then you are close to proper, and it will take only a bit of fan hlep to make sure you get exhausted proper.

 

[Thaifighter]

great thread hoosier... quick question... I have a 4x4x7 room and a couple months ago i put a 5000 btu a/c in the window.... with my previous setup i had a pair of 4'' computer fans for the intake with another fan for the exhaust, the intakes are still installed and my room is working fine but i was just wondering do i still need them? or can i just seal the room with the a/c alone?

 

[petemoss]

Nice work, hoosierdaddy! Love your tutorial and illustrations!

 

[hoosierdaddy]

Thanks, petemoss. Your kind words are appreciated.

Thaifighter, In my situation I intake fresh air and scrub it out, even with the ac. For security reasons it is always best to have a negative air pressure flow in the room, and scrub the exhaust air. If you want to do a sealed room, it needs to be just that , completely sealed. And then it should really have a controlled air flow situation on top of that so it has the ability to vent in/out air when the conditions warrant.
If you stay in that sealed room, comes a time when you deplete the atmosphere of what you need to survive. Same with the plants.

 

[swampdank]

You must spread some Reputation around before giving it to hoosierdaddy again.

 

[Calimed]

Very nice post full of useful info. I have one question though, is this basically modding a window air conditioner to be a dual hose portable? Would it be more effective to mod a window unit or just buy a portable. I can't find many or any dual hose portables for under 500 so maybe I just answered my own question.

 

[Hydro-Soil]

You must spread some Reputation around before giving it to hoosierdaddy again.

You're quite the artful Hoosierdaddy. I quite enjoyed this thread.

 

[hoosierdaddy]

Calimed, I paid $89 for my 5050btu unit at WaldoWorld.
I can buy a new one every two years just to keep it fresh, and will be money ahead of the portables. They also suck up the juice too.
But, yes...this is a ghetto portable that aint so portable.

 

[DIRT DIGGLER]

great tutorial HD.

 

[DankHawk]

Does it matter how hot it gets inside the exhaust box? 125f too much?

 

[hoosierdaddy]

You will have a hard time cooling the tubes with such hot air. The units are designed to work in normal outdoor temps, and it will probably work using 125f air...but at the cost of the unit's longevity.

Where are you getting this hot air? Your lights?

 

[DankHawk]

Thats what I was thinking.
Ill need a bigger fan.

No lights running. Just tinkering with getting everything running smoothly.

 

[Danknuggler]

OK i'm gonna build one of these as I was gonna go blow 500 on a portable but now this, thank you HD!!One question.I am running 2 600's and a 1k (2200watts) all ventilated what size window AC should I go with?My room us 6.5ftx6.5ft x8ft ceiling.Could I get away with a 12000btu ya think?thanks for any help.nuggler

 

[hoosierdaddy]

Both the ambient temperature of the air surrounding your room, and the amount of ventilation air you have going to/through the lights will effect the grow temps.
The better you have the room insulated, and the more air moving though the light fixtures, the less BTU's of cooling you will need to keep the room at a good grow environment.

When it comes to sizing the AC unit, it's all relative to the above.
And a smaller unit can do the job of a larger unit, it will just have to work harder to accomplish the same task. A small 5000btu window unit can do the same job as the $500 portable, but it may not live as long as the portable...BUT, the small window unit costs around $100...so you can go through 5 of these units before you would be at the money that portable costs.
Insulate your room with insulation board or material of some sort, and put lots of air through you light fixtures, and the requirement for cooling becomes less.