Diy Building An Exhaust Box For Window Unit Indoors

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This is a DIY in building an exhaust box to use a window shaker a.c. unit indoors.

Tools needed
-box material. I used R max R matte +3
good for up to 250*f and is 3.2r value
- sharp knife
tape measure
3m hvac tape (don't use duct tape)
Little common sense
6" flex duct joiner/sleeve piece
6" 90* elbow
Hose for drip tube

after you mount your a.c. and like it's final position, it's time to build your exhaust box. I made my box with 2 layers of material for added protection. Build 1 section at a time. Fully secure at each spot. I personally do 3 layers of tape (overlapping each other like a brick wall for support). See pics below for details. I use a 6" duct joiner/sleeve
Mounted on top where I attached my insulated flex duct to for the exhaust part. I did 2 layers of the board material. This gives me a 6.4 R value. Noise is barely heard as well. There is no heat on the boards, donuts insulated well.

I will also build a shelf support under the bottom of the exhaust box just for added support. Only thing that's holding it is 3m hvac tape. But it's secured very well.

Pictures will.help more than my description, I'm sure.

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I ran this for 2 days w/o any issues. Minus my master controller not being able to handle the power draw. Hence the reason for me building a 40a controller below.


Stay tuned for my DIY light controller. Although it's cheaper to buy prebuilt one.
 
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When making this, I did 2 layers for peace of mind. Build your 1st box, then the 2nd on top of the 1st so you get a good deal and fitment of the boards. I thought the box would have made the exhaust noise loud, but you can barely hear it. I may also run another layer of tape on the outside just for added security.

This foam board was the ONLY one u found with a high *f rating. The exhaust of an a.c. does get hot. So be careful with the material you use. Also, I did NOT use any caulk or sealant. Imo, the heat from the exhaust will just make it gooey and melt.
 
Were you using a 6" fan to pull the air out of the box? I was building something similar to this and was curious as to how you could make the "exhaust" fan kick on when the a/c was running. How high of temps were you getting inside the box?
Thanks
 
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I Use a light controller as power supply for a.c. and exhaust fan. Use trigger cord, plugged into greenhouse controller.


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263
would u take that 3m and put it on ever inch of pipe that will hold that heat I got a new floor ac and having lots of piping and its crazy hot
 

Jack og

JackOG
Staff member
1,847
263
would u take that 3m and put it on ever inch of pipe that will hold that heat I got a new floor ac and having lots of piping and its crazy hot
They sell, “dual wall” pipes, that we use in the hvac industry that is used for exhaust on furnaces, that would suffice, tape doesn’t do anything other then retain heat. Just seal gaps with it. The dual wall has an inner and outer layer, outer layer is cool to touch. Use an in-line fan to “ pull from your plenum box. They also sell condensate pumps, 110v that will pump out your water condensates, very low amps so power consumption is low. It’s actually very clean water that “can” be used to water plants with.
 
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263
water comes out nice n cold as well how I had it set up was not working for me so I said f it and just put it n a window now my room gets down to 64 at night so had to set the temp
 
This is a DIY in building an exhaust box to use a window shaker a.c. unit indoors.

Tools needed
-box material. I used R max R matte +3
good for up to 250*f and is 3.2r value
- sharp knife
tape measure
3m hvac tape (don't use duct tape)
Little common sense
6" flex duct joiner/sleeve piece
6" 90* elbow
Hose for drip tube

after you mount your a.c. and like it's final position, it's time to build your exhaust box. I made my box with 2 layers of material for added protection. Build 1 section at a time. Fully secure at each spot. I personally do 3 layers of tape (overlapping each other like a brick wall for support). See pics below for details. I use a 6" duct joiner/sleeve
Mounted on top where I attached my insulated flex duct to for the exhaust part. I did 2 layers of the board material. This gives me a 6.4 R value. Noise is barely heard as well. There is no heat on the boards, donuts insulated well.

I will also build a shelf support under the bottom of the exhaust box just for added support. Only thing that's holding it is 3m hvac tape. But it's secured very well.

Pictures will.help more than my description, I'm sure.

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Seems like alot of unnecessary work just let the hot air vent into the garage /room.
 
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