Packing peanuts for insulation in a solar kiln

[brdmkr]

I have the offer of 60 cubic feet of packing peanuts for free.  Do you think they would make decent insulation for the walls of a solar kiln?  Just trying to save some cash.

[Burlkraft]

I don't know about insulation, but have you priced those DanG things

I just had to buy a big bag of them and they were 50 bucks

I was shocked, but needed them right away, so I bit the bullet. Cut into my profit for that series of turnings

If I was you I'd grab them peanuts......you could always donate them to the auction

[brdmkr]

I think that is about what these cost.  I sure don't need them if I can't use them for insulation.  I'd be reluctant to offer them for acution because of shipping charges.  They are light, but bulky.

[Tom]

you couldn't pay me to off load them here.   I hate those thngs.  Everytime I open a box my wife gets from HSN the yard is full.  Have you every chased a thousand packing peanuts on a day with 10mph wind?

It makes you want to back-charge the shipper.

[Dan_Shade]

hah, yeah, you'd have to pay me to take them too.

if you can get a hold of a few, put them in a cup of water and see if it soaks up the water, or just kinda floats in it.  if it soaks up the water, you don't want them.  if they float, you might want them.  I have no idea of the R values

[Burlkraft]

The one's I just bought, if you put them in water they disapear........

So if they are rollin' around the yard just wait for rain and they will be gone. I think they even suggest that you throw them in your compost pile

[Den Socling]

I wish the things would be banned. I hate digging though a box looking for the goods, I hate cleaning peanuts out of cavities when some jerk hasn't put stuff in plastic bags and I hate cleaning up the mess afterward. But as to R value. I think you would need to compress them to close the spaces.

[brdmkr]

The peanuts I have access to are foam and will not dissolve in water.  I hate the things too, but if I can get some use from them, why not.  I wonder where you go to get the r-value of peanuts???

[isassi]

The value of insulation is based on the ability to "trap" air, since it does not conduct heat energy readily. I doubt the peanuts would have a lot of value. One idea you might think of is check with a local steel building erector. When we put up building, we always have pieces of 3 inch vinyl back that usually ends up at the dump. I am saving all my pieces now for the solar kiln I am going to build later (just as soon as I figure out how  )

[DanG]

This brings up a question that has been bugging me.  Insulation works by trapping air, right?  If that's the case, why not just use air as insulation?  I'm not posting this as a suggestion here, but purely as a question.  If you were to seal up the wall with a dead air space between the outter and inner sheathing, wouldn't you be doing the same thing as stuffing it with insulation?

[Weekend_Sawyer]

 Back in 84' I worked in a nice new computer facility with raised floor and positive pressure under the floor to cool the equipment. Well someone dumped a box of packing peanuts under the floor and the first couple of times I pulled a floor tile Hundreds of them would blow out. Years later we were still getting a few here and there.

I hear that some are made of organic material and will biodegrade.

Jon

[Tom]

Dan, I've thought the same thing and have given it considerable thought.   Listen to this as I re-invent the wheel.

Dead air is what insulates.   Trapping air in the small confines of a foam  or in the spaces between the particles makes for an area where heat is slow to being lost.

Here is why a closed wall is difficult to use for insulation.

It's hard to really close the wall.  There is wiring, plumbing, and structure that connects the outside to the inside.  The structure parts convey heat.  The plumbing and electrical need holes.  You can't really seal a wall very good.

A large space of "dead air" can set up convection currents that carry the heat from one side of the space to the other and that allows the heat to dissipate.

The reason that wood, foam, paper-shredding or glass fiber works is because the spaces are tiny and encapsulated. What little air there is, can't move around.  Even if you heat it up, the heated air has trouble getting to the lesser heated air.

Logs in log cabins have a high R value because of the little air spaces in the cells in the log. Concrete block has a big air space but its main failure is that concrete joins one side of the wall to the other and allows heat to dissipate.

Two by Four studs in a wall will dissipate heat, as well as sound, from one side to the other. That's why a 2x6 wall made from alternating 2x4's, with insulation woven between, makes a quieter and warmer room.

That's my layman's view.  I don't know if I'm really right or not, but it satisfies my curiosity.     Now for an engineer who really knows.  

[isassi]

I'm not an engineer, but....you are right. Actually, the most ideal "insulating medium" is a pure vacuum. That said, we all know you can't do a vacumm practically. Remember when the first "energy" windows claimed a vacuum seal? When the vacuum was finally broken, they trapped condensation and fogged. Then they did inert gas whick transmits heat less then molocules of air. Since air has molocules, and those molocule do conduct heat, the idea of "tiny" air entrainment is to break this conductivity. I think that is a simple as I understand it. 

[pigman]

That's my layman's view.  I don't know if I'm really right or not, but it satisfies my curiosity.  

I am more of a sitting man, but it sounds good to me.  
In any sealed space containing air, there will be air currents if any two wall surfaces have different temperatures. As joasis has stated, if there is a complete vacuum there can not be any air movement.  What I like about  this forum is I can say just about anything and if I am wrong some body that knows will correct me. The secret of any heat insulator is to get as many tiny air spaces as possible without the walls of the spaces becoming heat conductors themselves.

[brdmkr]

OK, so what about the peanuts?  Would having a bunch of them with air all around them be essentially the same thing as having nothing at all?  Or, would there be significant insulation?  The last thing I need is three truck loads of peanuts with no R-value . 

[Tom]

To fill a space with peanuts could make it more difficult for the air around the peanuts circulate from one wall to the other.   So, I guess it would have insulating value.  How much would be the question.  I don't know.

[Dale Hatfield]

I think that they would provide some R value.  But very little for the same reason that they are used for packing.Based on the air space that they will hold .
 Depending on the style of the packing  material would also  increase or decrease R value. Some of the shapes will hold more air than other more air space =less R value
Think about blown in insulation as much as contractor hates working with it. It makes a very dense area in the wall.
I think that the contents of a bean bag would make better insulation with higher R value.
Brake  the structure of the packing down and the R value should go up.

Dale

[Mr Mom]

     If its alot could you some how grind them up???
     You could take plastic and make tubes then stuff them in it like ins then stick them in the stud opennings.
     Just thinging.





     Mr Mom

[isassi]

Ok, I looked in a few of my product specs...and roughly 3 inches of molded expanded polystyrene has an r value of about 18, 2 inches 12, 1 inch 5. And these are for "dense" EPS. Shipping peanuts, unless crushed and packed, would have very little ability to insulate, but I guess, better then nothing at all. Blanket vinyl back insulation like I will use costs me .31 cents a square foot...so depending area of walls, ect. it can be pricey or cheap. What I tell me customers with regard to insulation is "you only pay for it once, you pay utilities every month". I guess that it wouldn't apply to a solar kiln, but I will insulate mine with end of roll scraps...try to keep all the heat in.

[DanG]

Well, I'm pleased.   That little question accomplished 2 things.  First, it told me why my thought was lacking, so I can sleep better now.  Secondly, it told me some people besides me actually read this part of the forum.

Mike, get the DanG peanuts!  Shanghai Eric's Cub Scout Den into stuffing them into small plastic bags, then you can install them into your wall.  The bags will keep it from settling.

[brdmkr]

DanG geeeenious idea.  Dan.

[Den Socling]

I said to compact them to reduce the space around them. If you took a cavity in a wall and filled it full of those foam peanuts and then you compacted the pile from above to close the space between the peanuts, they would be insulation.

[Rockn H]

Polyurethane foam insulation has an R value of between 6 and 8 per inch depending on density according to most manufacturers.  So if you have 6 inches of "solid" foam you'd have an R value of 36.   Dead air space is only bad because of convection, right?  If you fill the wall from the top ,and compress the heck out of it ,won't the peanuts be packed tight enough to assume at least 5 solid inches?  That would be an R value of 30.  Even if you knock off another inch, you're looking at an R value of 24.  That would be as good as your standard fiberglass insulation.  Heck if you can get enough go with a 10" wall cavity.  That's about how thick they used for ice houses and all they had was sawdust for insulation.  If it's free try it.
If any of my figures are too far off somebody correct me.

[WkndCutter]

Those packing peanuts will afford some insulation value but there will be some settling over time.  Putting them into plastic bags will help with that.  Depending on your wall size you will need around 2 cuft per wall stud space.  The cost to insulate the whole kiln is going to be considerable using regular fiberglass or sheet insulation.  I would put the packing material into plastic bags and seal the walls on both sides with plastic sheets before putting the wall board on.  Bottom line, free insulation - you can't throw that away.

Andy

[Brad_S.]

I've looked into the foam insulation and consulted a number of 'experts' and all give me different answers. But they all kind of agree that R values are misleading. I was pricing walls 5 1/2" thick and was told "why bother" 1 or 2 inches of foam is better than 5 1/2' of fiberglass, not because of R value but because there is much less air infiltration with the foam. I think-and I have no expertise, this is just a supposition- infiltration around the studs would be the weak link of the packing peanuts.

[isassi]

This got to be really in depth..so here is another look. EPS is great insulation, no doubt. Fiberglass is better still (barring air movement). When we rehab older houses, we now vapor block the external walls, bat the inside, and sometimes moisture block the interior as well. New premium vinyl siding has insulation molded to the siding and flat to the house. This system only promises an "R" gain of 6 or so. R value is a very misleading term for a blanket approach. The bottom line is most homes and buildings are not air tight, leading to heat/cooling loss. All things sealed, then the building materials conductivity is rated. 3 inch fiberglass has a much higher r value then stated, but due to 2X4's and framing, ect. it can not block tranfer, so the rating is only arbitrary. That is why an inch of EPS board on a well insulated house gives such a boost, especially combined with a house wrap and caulking + taping the seams of the EPS with foil tape. Now for the numbers: Insulation is the cheapest by far of all materials to build with, and if the wall cavities allow it or you have access to spray equipment, blown cellulose is a great insulator and is nearly all from recycling. )less the 20 cents p/s/f. 

[brdmkr]

Well, I suppose I will be the proud ownert of 60 cu ft of peanuts!  Man, I hope they work.  If they don't I'll have a mess

[DanG]

Blown cellulose is great insulation, but not recommended for kilns.  The high humidity from the drying wood will soak it with condensation, and it will cease to insulate.  At least, that's what the "Doc" says.

[isassi]

I hadn't even thought of that dang.....very valid point, so I suppose we shoudl say that EPS board would be the best. Thinking further, all those peanuts would trap water in the bottom of the cavities also.