# *Safely* insulating a portable air conditioner's exhaust tube. How?



## Trashman (Apr 22, 2009)

Title says it all. Our apartment reaches ungodly temperatures in the summer. Lately, it's been around 90 degrees in Glendale. Tonight, the thermometer in our room says it was 86.6. Not very comfortable for sleeping. Last night, it was over 85 in the room (even at 3am), and sleeping wasn't easy. Tonight, I hooked up the portable air conditioner that we use during the summers. The thing is, I've never insulated the exhaust tube, and it really needs it. The wireless outdoor temp sensor for our clock sits on the window sill, by the side we leave open, and it gives us n reasonably accurate representation of the outside temp. Right now, that sensor is underneath the exhaust tube, and it's reading approximately 93 degrees. Not good. Even though the thing is blowing cold air, the exhaust tube is heating up the air behind it. I've been wanting to make some type of insulating sleeve the exhaust tube, but have never done it. I've checked home depot to see what they've got, but the only type of insulation there is the fiberglass/mylar type, which I don't want to use, because of the breathing hazards. (especially, since we've got a infant in our room) Plus, it wouldn't be very pretty to look at, either.

I'm sure there must be some CPFers with the same type of portable air conditioners, and I just bet that they've already solved the problem of insulating the exhaust tube. If you've done it or have any good ideas of how to do it, please, speak up! I just know it will make quite a big difference in lowering the temperature of our room. Just a couple of degrees would be major.

So, come on, let's hear it!


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## StarHalo (Apr 22, 2009)

This is an interesting problem, let's hope for some creative responses 

My first instinct would be to go ahead and wrap the tube in insulation using duct tape, then add a layer of cling wrap to seal it completely.

Another option would be to use header tape (http://www.autobarn.net/exinwrbyth.html), but I don't think that would would nearly as well as plain fiberglass bundles..


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## Trashman (Apr 22, 2009)

I would like to avoid fiberglass, altogether. Online, I found some type of insulation that is made from denim scraps, that's supposed to perform like fiberglass, yet carry no health hazzards. It looks like it's a little on the thick side, however. I'm planning on walking down to Joanne's (fabric store) and see if they've got any type of insulating material that can be sewn. I think, something like what is used in pizza delivery bags might be the answer, but where to find it?


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## tygger (Apr 22, 2009)

Maybe try Reflectix insulation? It comes in the big silver rolls next to the styrofoam boards) at Home Depot. Here's their website if you wanna check it out. Any construction/duct work people here to chime in?

http://www.reflectixinc.com/

Oh, I've used it to make a homemade freezerbag koozie for camping after reading about in an outdoors article. Worked really well.


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## bitslammer (Apr 22, 2009)

Bubble wrap should help quite a bit.


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## Norm (Apr 22, 2009)

Something like this Nitron Industries Insulation
Norm


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## DUQ (Apr 22, 2009)

tygger said:


> Maybe try Reflectix insulation? It comes in the big silver rolls next to the styrofoam boards) at Home Depot. Here's their website if you wanna check it out. Any construction/duct work people here to chime in?
> 
> http://www.reflectixinc.com/
> 
> Oh, I've used it to make a homemade freezerbag koozie for camping after reading about in an outdoors article. Worked really well.



+1 :twothumbs


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## Trashman (Apr 22, 2009)

tygger said:


> Maybe try Reflectix insulation? It comes in the big silver rolls next to the styrofoam boards) at Home Depot. Here's their website if you wanna check it out. Any construction/duct work people here to chime in?
> 
> http://www.reflectixinc.com/
> 
> Oh, I've used it to make a homemade freezerbag koozie for camping after reading about in an outdoors article. Worked really well.




Thanks! I'm going to go check that out. It looks like it might work. The Nitron stuff also looks like a good candidate. I like that it comes in colors and, from the sound of the description, appears that it might be very similar to neoprene. Not sure where to find that one, though.


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## chmsam (Apr 22, 2009)

Have you thought about calling an HVAC shop and asking them what they'd use or suggest? Might cost you a box of donuts for their advice but they are the experts, you'd have a really good chance of it working well, and they'd know where to get the stuff. Just a thought.


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## LitFuse (Apr 22, 2009)

Is it possible to put a regular window AC unit in that window? They are much more efficient at cooling than the portable units, particularly if the portable is a single tube model.

I realize that that isn't what you're asking, but it might be a better fix for the problem?

Peter


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## jugg2 (Apr 22, 2009)

I work in the HVAC industry, and the standard insulation is fiberglass unfortunately. Properly applied, stapled, and taped it shouldn't be a health hazard at all, but I understand your concern. I have heard of some type of metallic bubble wrap (for lack of a better description) that a few companies are trying out, but I have never seen it or delt with it.


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## Diesel_Bomber (Apr 23, 2009)

What temperature does the output hose get up to? Could you buy a bunch of cheap fleece by the yard and wrap the hose? Zip ties could hold the fleece in place.

:buddies:


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## jzmtl (Apr 23, 2009)

See if you can find roll of self adhesive foam with aluminized side from home depot, I bought some to make gasket but I'm pretty sure it's meant for insulating pipes.


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## Trashman (Apr 23, 2009)

More good suggestions! What's fleece? Like fabric? I've not gone down to Joanne's, yet, but I think I'll take a quick walk down there, now. I don't really want to put a box unit in the window. It's going to be a hassle, inconvenient, a pain, and, probably unsightly, after the huge gap above it it blocked. I'll check the temp of the hose. It gets pretty warm. I was also thinking, that I could buy a couple those food insulating bags they sell at Costco for $3, and cut them into strips and somehow make a sleeve out of it.


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## jzmtl (Apr 23, 2009)

Trashman said:


> More good suggestions! What's fleece? Like fabric?



It's those fluffy polyester sheets, I wonder if you can pick up some fleece blanket from salvation army store for cheap and duct tape them around the pipe.


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## Flashlight Aficionado (Apr 26, 2010)

Trashman said:


> The wireless outdoor temp sensor for our clock sits on the window sill, by the side we leave open, and it gives us n reasonably accurate representation of the outside temp. Right now, that sensor is underneath the exhaust tube, and it's reading approximately 93 degrees. Not good.



The sensor is wireless. Couldn't you move it to another window in another room?


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## StarHalo (Apr 26, 2010)

[Thread is from last year]


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## Flashlight Aficionado (Apr 26, 2010)

StarHalo - Wow your right! How did it get bumped to the first page? I swear it was labeled as having new posts before I replied. That is very weird.

Time to post in the Questions/Problems/Suggestions section.


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## StarHalo (Apr 26, 2010)

A newb posted an advertisement in the thread, which bumped it to new status, then one of the mods removed the ad.


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## Diesel_Bomber (Apr 26, 2010)

Fleece blanket material will handle 93 degrees no problem. What'd you wind up doing, TM?


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## Popsiclestix (Apr 26, 2010)

I assume this is one of those room units that exhaust through a cheap slingy type plastic tube outside? I have a 1 kW unit made by sharp in my room. 

May I ask why you think the tube needs more insulation? Are you sure it is not just the sunlight shining directly on the temperature probe so that it is artifically inflating the temperature?

The VAST majority of expelled heat is carried in the moving air mass and very little is actually transferred to the exhaust tubing. I can go into first approximation calculations if you want, but I doubt you're getting even 5% reemitted back into the room. You're not likely to gain much by wrapping the exhaust tube of such a small unit.

It almost sounds like you have a leak somewhere along the tube.


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## StarHalo (Apr 26, 2010)

*
*
* Original post is from April 2009* 
*
*


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## ElectronGuru (Apr 26, 2010)

At the risk of continuing...

All insulation has to do is keep air from moving about. Not all insulation is industrial, a pair of pillows on either side insulates all kinds of things.

But as has been suggested, this is not the problem. The machine is sucking in air from the room, heating it up, a blowing it out the exhaust tube. This action creates a vacuum in the room itself. To replace this air, "the room" will suck it in from the least sealed panel, door, or window. In this case, from the very window doing the exhausting - drawing hot air right back in.

Portable units should only be used when window units cannot be.


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## andyw513 (May 5, 2010)

I've heard of spray-foam being sprayed in it before, but I don't really think it is that great of an idea. We have adhesive-backed foam in ours and it works well enough.

On a 'light'er note, this thread reminded me of this past winter: This guy takes a Keystone Light box and insulates a pot-belly stove pipe with it...inside his house...and the pipe was ran out of a single-wide window.


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