Radiant Barrier Insulation

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  #1  
Old 01-13-03, 01:15 PM
Brewbeer
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Radiant Barrier Insulation

I am interested in learning more about radiant barrier insulation systems and how they compare to more traditional insulation systems such as fiberglass, cellulose, and extruded polystyrene in cold-weather climates.

Also, can anyone point me toward any independent studies of the performance of these various insulations types in cold climates?

Thankx.
 
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  #2  
Old 01-13-03, 01:45 PM
Ed Imeduc's Avatar
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Insulation

Well you will get all kinds here thats for sure.Im on the side with FG and also cellulose with a 2mil poly on all the inside walls and ceiling for a good vapor barrier. FG will melt in a fire where cellulose wont and can stop the fire. I find the polystyrene will take in moisture in it and after that there is no insulation at all. There are some good www for the sales of RB and what they say. But how come some of the power comanys back away form it. WE get about an R28 in the wall and A R40 in the ceiling.All of the windows triple track with a vinyl seal between the out side frame and inside frame so they dont sweat. This way low fuel bills ED
 
  #3  
Old 01-14-03, 12:38 PM
rbisys
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Greetings,

Well ED, I'll tell you why the power companies don't recommend RB. It's because a RB home uses 40-50% less energy. The two local major utilities have killed alot of sales for me over the pass 29 years. They are definitly not our friend. They won't even invite me to their energy semminars. I wonder why? I have had a couple of friends and contacts in utility cos. and they wre told to shut up about RB.

According to NBS report, cellulose holds about 50% more moisture than FG. You figure 5% increase heat flow for every 1% moisture. They reported about 14.4%. FG about 9.6%.

By the way you are lucky if you get "R" 20 from a "R" 40 batt. That's like buying a new car with 200 hp only to find out it's 100hp. You can thank the bedroom connection of the government and FG mfgs for that deception.

On a 95 deg day, unshaded roof the ceil'g temp of FG isabout 110 degs. That's 37 btus/hr/sf. We can do a RB ceil'g that is only about 5 btus/hr/sf. Little or no a/c required depending on the house design.

For FG ck FG litigation, FG mold problems, FG cancer problems, on the web. Try the same for RB.

I looked into cellulose about 25 years ago and found it not as eff as RB.

Thank you for my opinion.
 
  #4  
Old 01-15-03, 07:43 AM
Brewbeer
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rbisys,

you used an example of a roof on a hot day. I live in a cold climate, and am more concerned about how well this system insulates against the cold.

Can you provide me information and/or links to independant studies comparing RBI to say, extruded polystyrene? I am doing a basement project and need a system that is not a vapor barrier.

The issuse I have in my mind that I don't understand is how does a RBI system which is relatively thin, resist conduction of heat from a warm space to a cold space?

Thankx.
 
  #5  
Old 01-15-03, 11:37 AM
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  #6  
Old 01-15-03, 12:29 PM
Ed Imeduc's Avatar
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insulation

OH man that is a good www you gave there resercon. As I see it there. If you have very little FG insulation and you put RB over it you save $$$$$.But when the dust and dirt get on the RB you just dont have anything. Then the home that had R19 FG and put another R19 on top of it got $$$$$$$$ back year after year. Thats what the US GOVT. said. Now I see why the power companys dont like RB.
ED
 
  #7  
Old 01-21-03, 05:47 AM
rbisys
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Greetings,


Thank you for considering my opinion.

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The entire content of the thread was edited out simply because it did not contain information that was helpful to the member asking the question nor regarding the originally asked question.

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Last edited by Sharp Advice; 02-11-03 at 07:44 PM.
  #8  
Old 01-21-03, 07:36 AM
Brewbeer
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rbisys,

Obviously you have your opinion. We all do. However, what I am interested in is not your opinion, but the reasoning and rationale that is the basis for your opinion. That is why these forums are great - you can get all the info you like, do the research, and come up with your own, educated, opinion.

rbisys, please describe why you believe Ed is wrong. Please give us some real, hard information (not just your opinion).

Also, the DOE publication referenced above indicates that radiant barriers are more effective in reducing cooling costs in warm climates vs. reducing heating costs in cold climates. Do you have some information from some other independant studies that you wish to bring to this forum?

Thankx. --=--Brew
 
  #9  
Old 01-21-03, 09:09 AM
Ed Imeduc's Avatar
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RB insulation

This I do know. Your home power company dont want anything to do with this RB. The gov www. said you save more $$$with more FG than you will with the RB and how it goes down hill over the years just from dust on the RB.I have put up the fuel cost for one year on a home the way we do it. I asked you to do the same. Also as far as A/C down south .We have found that for less cost than the RB a power vent fan on a roof pulling air out of an attic is worth close to a ton of AC at very low amp draw ED
 
  #10  
Old 02-11-03, 07:30 AM
Brewbeer
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ok rbisys, now that you are back posting to this board, would you be so kind as to directly address the questions posed by the posters on this thread?

Thank you for providing the information that all we DIY'ers need to make informed decisions.
 
  #11  
Old 02-11-03, 06:02 PM
rbisys
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Greetings Brewbeer,

Thanks for reminding me of your ?'s. I read them, then was away for awhile and forgot about them.

I belive you will have to contact the RB manufacturers for test results and comparisons. However there is one thing you should know if you don't know it already. The c- series tests that are used to give FG and cellulose their "R" factors are not tests that reflect the installed summer/winter conditions. They do not include humidity or condensating conditions. If fact the delta T is 30-35 degrees, mean about 70. This does not represent the operating conditions of your home. The reason that this test was initiated into the system was because FG will get about 50% less "R" value than advertised and who would buy it. This is one reason why FG is not listed in any of the building codes. The codes require installed condition tests.
The US Senate in 1981 stopped operating funds for the FTC when they put into effect regulations that would require all insulation rmanufacturers to test installed conditions. This would mean a 70 degree difference for winter and at least 100 degs for summer with a min of 80% rel humidity. These test would be for a min of 120 hrs not the short test used now. All this is on record. Prior to this in about 1958-9 the US Senate banned all RB from government jobs at the request of the mineral wool industry because RB at that time was growing by leaps and bounds. Personally I don't think the RB industry ever really rebound from that. But, they are growing and more and more people are learning.

So if the tests are favored towards big business how do you get the truth? You go to a mechanical engineering handbook and look up the emissivity factors for the base material of the insulation. For glass it's about 95%. That is, it absorbs and remits about 95% of the heat energy striking it. Same for wood.
Another factor, glass only makes up about 2-5% of the batts mass. The rest is air spaces and radiant energy, traveling at the speed of light, passes right thru. This does not include any of the problems from moisture present. If you notice FG people act as radiant energy does not exist, but if they did admit it they could be sued out opf business. Their whole concept is based on lies easily seen if you KNOW YOU'RE BASIC SCIENCE, which you should have studied in high school zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx All of this info is available on the internet.

Foam which is made from petroleum prods is about 20% efficient.

When you get to metallics, gold, alum, copper and some others are up to 97% efficient. Since the c- tests are not applicable to RB and RB tests are not applicable to mass insulation, is there a common factor for determining what is really going on? Yes.

On the page previous to the emissivity chart is a formula that tells you the amount of BTUs radiating from one surface to another based on the temps involved. For instance a FG ceil'g on a 95 deg. day will get up to about 110 degs. If the floor temp is 75 degs the BTUs radiating from the ceil'g is 37/hr/sf. If you have a foil up there dividing the air space in the joist, at 110 degs, the BTUs are abot 2-3/hr/sf. Let's go back to the 97% eff. This 97% is for ALL DIRECTIONS. So, how does the DOE come up with their little slander? Easy. Above you noticed that there is a considerable diff in the delta T of summer and winter. Less energy available in winter. RB will show an increase in efficency when the temp differences rise, FG will do the opposite since it is mostly air. Second the dynamics of heat lose in winter is different than summer. In summer the % of radiant heat down is 90%+, conduction and convection up to 7%. In winter the radiant is less and conduction and convection up. Now this is common knowledge among experts in the field, and available to you on the internety, SO, WHY DOESN"T THE GOVS POINT THIS OUT. For the same reason the govs don't tell you alot of things you should know in order for you to make wise choices. Remember, and you know this, the gov is one super marketing promoter for industry. Industry provides jobs and materials to be taxed and to give to the political parties.

Why is it so hard to accept. We ***** about it all the time and we see how we are ignored.

I appeciate everyones desire for me to give all the answers. I can't. For one thing I would be writing the same thing over and over again as I am doing now. Second I am not in the position to forward all the data I have on paper and in my head. All this data, and more, is on the internet. If a peraon is really motivated to explore and learn, not only this, they will learn regardless of what I say. By the same token God Itself could come down and Bless RBs and there are people who wpuld say You're full of *********************. This like anything else is a learning experience. We learn what we want to learn and nothing else.

Now I have made a couple of drawings and written instructions on how to super insulate with RB. If you want a copy out of couriosity or to try out send me an e-mail with your address.

Thank you for considering my opinion.
 

Last edited by Sharp Advice; 02-12-03 at 06:21 AM.
  #12  
Old 02-12-03, 06:34 AM
Brewbeer
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rbisys,

kindly post the URLs to the internet links you discuss above. I am VERY interested in seeing the information you are referring to.

Also, it would be very easy for a college graduate student to construct 2 identical boxes, put identical containers each containing a gallon of water inside each one with a thermal probe to a remote display, and insulate one of the boxes with RB and the other with, say R-13 fiberglass, put the two boxes in a large walk-in cooler, and measure the decrease in temperature of the water as a function of time.

This is the kind of information that I would consider to be the gold standard for making an independant and informed choice.
 
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