Is bubble wrap duct insulation Energy Star approved, and is it a good idea?
GBA Editor
| Posted in Building Code Questions on
I spoke with a HVAC installer who said he wanted to insulate my ducts with double-wrapped bubble wrap as a cheaper way to achieve R6. Does this stuff really work and would it be Energy Star and/or ACCA Manual D approved? Would there be new problems created? I have never seen it done.
Thanks
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It sort of works but it's not Energy Star or Manual D approved and is generally viewed as snake oil by reputable builders. Use real foil faced duct wrap insulation after the ducts have been sealed with duct mastic and follow up with a duct blaster test to confirm quality of workmanship, preferably have the test done by someone not in the employ of the company doing the duct sealing.
Lora,
The claim that bubble wrap is equivalent to R-6 duct insulation is a scam and a fraud. One of the companies that sells this product — a company that has gotten into hot water for exaggerated claims — is Reflectix. When I was the editor of Energy Design Update, a reader asked whether Reflectix bubble-wrap could be substituted for R-6 duct insulation. This is what I wrote:
Reflectix insulation is a 5/16-inch-thick product consisting of bubble-wrap plastic sandwiched between layers of reflective material. According to ASTM C518 tests commissioned by Reflectix, the product has an R-value of 1.04. (Reflectix does not mention this R-value of 1.04 on its Web site; however, it can be found in a laboratory report available from the company on request.)
According to ASTM C518 tests performed by another insulation manufacturer, Glacier Bay (see http://www.glacierbay.com/reflxtest.asp), Reflectix has an R-value of 0.67. (The company also maintains a useful Web page -- http://www.glacierbay.com/Insultest.asp -- describing R-value test procedures, exaggerated advertising claims, and the Federal Trade Commission’s lack of zeal in enforcing the Federal R-value Rule.)
On its Web site, the manufacturer of Reflectix claims that the product can be installed as a duct wrap resulting in an installation with an R-value of 6. That claim is based on tests performed by the ICC Evaluation Service (www.icc-es.org/reports/pdf_files/ICC-ES/ESR-1362.pdf). However, the R-6 measurement is based on an assembly test, not a material test. The assembly used in the ICC Evaluation Service test includes not just Reflectix bubble wrap, but a site-built 3/4-inch-thick air space. In fact, the reported R-6 derives to a large extent from the air space, not the Reflectix.
To create the air space, an HVAC contractor must install 3/4-inch-thick plastic spacer strips every two feet along the length of the ductwork. The spacer configuration is described in the lab report: “Nominally 3/4-inch-thick by 1.5-inch-wide plastic spacers are attached to all four corners of the duct using Reflectix tape, with this assembly repeated every 2 feet along the duct’s length. Reflectix insulation is installed over the spacers and pulled tight to create a 3/4-inch air space. Joints are taped using Reflectix tape.” A Reflectix fact sheet advises, “If the duct is supported with saddle clamps, make sure to install a spacer on the two bottom edges of the duct directly between the clamp and the duct.”
Most HVAC contractors are likely to consider the construction of a three-dimensional site-built air space around installed ductwork to be labor-intensive and awkward, especially considering the difficulties of working around hanger straps. Moreover, the R-value of the assembly depends on the long-term maintenance of the 3/4-inch air space; if the Reflectix ever sags, the R-value of the assembly will drop.
The basis for the R-6 Reflectix claim is widely misunderstood; for example, an article called “Insulating Ducts for Efficiency” posted at Bob Vila’s Web site (www.bobvila.com/HowTo_Library/Insulating_Ducts_for_Efficiency-Insulation-A1780.html), recommends the use of Reflectix as an R-5.6 duct insulation, without any mention of the need for an air space between the Reflectix and the ductwork.
Here's a photo of what happens when this stuff is improperly installed...and I've never seen anything but improper installations.
http://picasaweb.google.com/jcsemm/BubbleFoilInsulation?pli=1#
Contrary to the above comments, a foil-faced bubble insulation is a very good way to insulate ductwork, especially in hot climates. Most people don't understand how an reflective-faced material can insulate, not that the r-value testing methodology doesn't measure the reflective/low-emittance properties of these products.
First, to address the previous post. This is a photo of foil insulation in a completely different application. Most likely, it appears to be installed here is a metal roofing application. The only way I can see this much condensation forming is if the area above the foil insulation is extremely cold, and the interior is very hot & humid. In this case, the lower surface temp of the foil facing could be low enough to reach the dewpoint, so condensation forms. Personally, this photo is vague. If this is a condensation scenario, I guarantee a fiberglass insulation would be a mold utopia. Quite frankly, it almost looks like moisture is accumulated above the insulation.
Ironically, condensation is one of the reasons a bubble/foil is a BETTER choice than fiberglass duct wrap. The two bubble layers provide a thermal break separating the duct metal from the attic atmosphere. Just as the material wrapped around a cold soda can would keep moisture from forming on the outside. Without this, the can would sweat. The airspace of the bubble helps keep your hand dry.
Condensation is a real issue with fiber-based duct insulations. Unless every seam is PERFECTLY sealed (which is very difficult to do), moisture will find its way into the material. This is why fiberglass products are notorious for harboring mold, mildew and other fungi.
As for performance, the problem is that most people don't understand how foil products can reduce heat transfer, by it's ability to (1) reflect radiating heat back to the duct, or (2) by it's INABILITY to emit heat from itself to a colder airspace (Low-Emittance).
(BTW...the foil facing of fiberglass duct wrap is NOT a radiant barrier. It looks like foil, does not possess the same low-emittance properties of the bubble-foil products. The key is the emittance value of the outer facing, based on ASTM test procedures.)
It's very sad that some believe foil/bubble products are a scam, or that our products are "snake oil". It's also sad that many in our industry are responsible for this reputation...by making false or exaggerated performance claims, recommending incorrect products or installation methods for particular applications, or simply not taking the time to explain when foil insulation a good choice...AND when foil insulation is the wrong choice.
I've seen foil insulation marketed for applications where I know the product will not perform, such as where no airspace exists. These are times when foil manufacturers have to accept that traditional insulation is the better choice. Our industry hasn't done that very well.
If foil insulation has such poor thermal value, why is it used in all spacecraft? Why is it used for emergency survival blankets (for both extreme cold and hot conditions).
Why is foil inside every astronaut's space suit, and not simply a mass insulation? Because if it weren't, the radiant heat from the sun would be quickly absorbed by the fiber insulation, and the heat would be fatal. But with foil inside the suit, this radiant heat is reflected away, and/or not emitted toward the astronaut. Foil is non-negotiable in these conditions.
That alone should lend some credibility to what a foil product can do. But here's the problem...The R-Value was created to measure an insulation's ability to reduce heat transfer via CONDUCTION and CONVECTION only. RADIANT transfer (simply put, the transfer of thermal energy into the air), is overlooked. The r-value test was created to isolate an insulation's performance to 2 of the 3 modes of heat transfer. Why? Because the r-value was created to by the industry that uses it to measure THEIR products only.
If anyone wants to know the true thermal value of an insulation, they need to look beyond the r-value alone. Unfortunately, that's not how our culture has been conditioned to think. We think the r-value is some magic number that will answer every question about an insulation's performance, but it's not.
Try wrapping a hot potato in foil and leaving it out to cool. Take another and leave it unwrapped. Occasionally, check the temperature of both, and see which one cools faster. The foil-wrapped potato stays hot MUCH LONGER, even though the R-Value of the foil wrap is R-0. How can this be? It's because an insulation can have great overall thermal value, and a low r-value. It is possible, but only with low-emittance materials.
Another myth about r-values...doubling the material thickness DOUBLES the insulation value. Nope...it only doubles the R-Value. Diminishing returns. ASHRAE has documented the diminishing returns of increasing R-Values, but nobody realizes this. The traditional insulation industries don't want you to know this either. It would cut their sales, if people realized the minimal incremental gain from increasing r-values.
Someday, foil insulation will be mainstream. People will eventually understand, and you can expect the traditional insulation powers to be the ones selling these products. Right now, the status-quo suits them fine. Someday, people will learn of the "amazing" and "newly discovered" benefits of foil insulation sold by the likes of Owens-Corning, Johns Manville, etc.
For now, everyone has to wait until this is good for them, too.
There's much more to explain. I'd encourage anyone to take a closer look at foil insulation for wrapping ductwork. The more you learn, the more you'll wonder why this isn't in your house.
I'll be glad to speak to anyone directly, and try to answer any questions.
Kelly Myers
rFOIL Insulation Products
800-837-8961
Kelly Myers,
Your post is a collection of half truths and outright falsehoods. It would take too long to address them all. However, I'd like to point out:
1. I stand behind my long post of Feb. 18.
2. Your statement, "The R-Value was created to measure an insulation's ability to reduce heat transfer via CONDUCTION and CONVECTION only. RADIANT transfer (simply put, the transfer of thermal energy into the air), is overlooked" is simply untrue. It is a falsehood invented and spread by marketers of radiant-foil products. To read the truth about R-value, check out "Understanding R-Value."
3. Your statement, "Another myth about r-values...doubling the material thickness DOUBLES the insulation value. Nope...it only doubles the R-Value. Diminishing returns" is also false. Doubling the thickness of a layer of insulation does indeed double its insulation value. It cuts the rate of heat transfer in half. The "diminishing returns" discussion is a reference to the cost of the insulation versus the cost of the energy saved -- an entirely different discussion from the one at hand. We're talking physics, not economics. Double the insulation and you cut the heat transfer rate in half. Period. End of story.
4. There's a good reason that foil-faced bubble wrap isn't considered "mainstream," as you put it. It is being sold by hucksters who believe in magic (and who always point to NASA, astronauts, and the space shuttle) instead of good old-fashioned physics.
I too have been incensed by the exaggerated claims buy the bubble foil folks. I'm an engineer and I have studied the physic (this is basic stuff) and know that air gaps work, and foil can reflect heat. But I drew the line when a contractor told me he could pour a slab and insulate it for radiant heat with a layer of bubble pack foil I drew the line. Reflective surfaces are not reflective if there is no air gap. So I did a bunch of tests with a heater in a box with different insulation around it. I waited until the box temperature reached equalibrum and figured that the BTU's going in are the BUT's being lost and I can calculate R factor. The tests showed an improvement of around R 2 for bubble pack over no bubble pack, same air gap. Less than what you would get if you replaced the air gap with foam. So why bother?
Sensible heat might be the reason. If you stand in a glass room in the winter at night you will feel a chill, no matter how comfortable the air temperature is. Cover the glass with foil and you will feel instantly much warmer. What's the equivalent R factor? Lots of people try, I am not convinced I believe the numbers, but I like the affect.
You can believe the numbers, since they are derived in the same way you determined the bubble-foil R-value. And this "foil-covered glass" is called lowE glass (glass with a thin metallic coating), the industry standard in the US. This is one of the best applications for radiant barriers, since most heat loss through a multiple-pane window is from radiant transfer between the panes. The other good application is under roofs in hot, sunny climates. Most of the rest is hype.
Doesn't most insulation work on the basis of air gaps? FG has a lot of air gaps and I thought that is where the insulation gets it benefit of being an insulation. Maybe the way that Reflectix states things is sketchy but their website does say that you need an air gap for ductwork. Now Martin, you don't really come out and say it but if you leave the 3/4" air gap with the bubble wrap, will you get R-6 or not?
It seems this material is more for the DIYer than a contractor. It does take time to install but a homeowner doing the work may not care.
And by using "real foil faced duct wrap" is that really any better in terms of install? Either way seems pretty intensive.
Thermal insulation works by trapping tiny pockets of dead air or other low-conductivity gases within a relatively non-conductive matrix - the smaller and closer the air pockets and the less conductive the matrix, the higher the R-value.
Bubble foil traps large pockets of air within highly conductive, closely-spaced foil surfaces, so it has almost no R-value. It does have modest ability to limit radiant transfer. If it's spaced slightly away from a heat-emitting material, the low-E surfaces will reduce radiant absorption and radiant transmission.
Reflective "insulations" work best with downward-flowing heat, such as from roofs to attics or from floor to cellar. It's possible to get as much as R-8 or R-9 in a floor with one foil surface enclosing a 4" air space. As soon as you tilt the air space above 45° toward vertical, internal convection undermines the radiant benefit.
The physics of radiant barriers is relatively simple. But much of the manufacturer promotion is hype.
Interesting debate. How about we get off of theory and get into the real world?
This past winter I did my ductwork with Reflectix: 2 layers and an airspace between (for the 3/4" airspace I cut 2 inch widths of it and wrapped it all the way around the duct twice. And did this every 2 feet.) Then I took my infrared camera, ran the furnace for awhile and then shot the plenum (which had no insulation) and got about 120 degrees. Then I went down the duct work a ways and shot again (all my ductwork is in the basement which is largely unconditioned). Got about 65 degrees. When I went down to the end of a duct run where I had not installed the Reflectix yet I got about 90 degrees. I had carefully taped the Reflectix joints and put extra effort into the bends. I moved the hangers so that they were always at the 4-layer points and never over an air space. My furnace does not run 100% of the time in (Maine) winter -- nobody's does. So it doesn't have to work 24x7. I'm confident that I'm ahead of the game and saving energy. Seems rather obvious, doesn't it? Your mileage may vary.
Oh, and it looks pretty impressive too -- if that counts for anything. Note: Before I started any of this I did a Retrotec Duct Blaster test and found and fixed all the leaky problems. I gained much, much more by doing that than I'd ever gain thru insulating the ducts. First things first. And I tightened up the house too, of course. Keeping that hot air in the house is the most important step of all !!
Dick,
What people euphemistically call the "real world" is typically no more than anecdotes. It sounds like you did a wonderful job sealing and insulating your ductwork, but if you were more aware of what you dismiss as "theory" you would know that IR thermometers are calibrated to read surfaces with an emissivity of 0.95 and cannot take accurate measurements on lowE surfaces such as bubble foil.
I realize that I'm playing "Thread Necromancer" with a 13 year old discussion, but you committed one of the worst, yet most common, sins of fallacy. I have worked, both in the lab, and in the field. I have advanced degrees in both physics and engineering. There's a good reason physicists and other lab workers aren't engineers. There's also good reason that plans GOOD engineers draw up have both safety factors and wiggle room built into them.
Scientists sit in their cushy labs, running carefully controlled experiments in a carefully controlled environment. Engineers have reviewed the science and done some implementation, but they also have some feedback from the people in the field, actually doing the work, informing them of conditions the scientists didn't factor into their carefully controlled experimentation. The guys out there, in the field, whether experienced contractors and laborers, or a rather handy guy that can install spacers and wrap a piece of insulation around them, then tape it all up nice and neat (many times not cutting corners the "professionals" do to save time and meet their budgets), are the people out in unknown conditions neither the engineer, nor the scientist thought to take into account. THEY are the ones who have to actually make it work.
Experience is NOT anecdote. The people you laud as being the most knowledgeable about using these products actually only know how the product SHOULD work, based on experiments that, by necessity of the scientific method, controlled the conditions of their experimentation so only one thing changed at a time for attribution. They know very little about how the product will ACTIALLY work when exposed to a million things they didn't realize it would be exposed to because they never leave the lab, or didn't have time to factor in. Engineers are not that much better. They take feedback, when people care to give feedback, but too many of them are just looking at numbers and running calculations. That's why I have spent a lot of my time on any given project out with the workers observing and talking, not to the foreman, but to the people actually doing the work, including the guy getting paid to pick up nails. There have been times where I've kicked the foreman out of his office to reengineer a part of a plant based on worker information. I'm a MUCH better engineer than 95% of what's out there, for it.
As far as this product goes, it has its place. It's great when you can afford to pay a crew to take the time and they do it right with the best tapes, spacers, and other materials. This stuff shouldn't sag for 30 years, unless it was improperly installed or somebody skipped on materials.
Too many construction companies aren't willing to take the time to do it right because they want to get the job done, collect a bonus, and move into the next job. Too many PMs will see expensive materials bring used and run a Google search for something cheaper so they can get a bonus for coming in under budget. Too many clients just want to get into their building and start hounding the construction company to hurry up and get done. The workers are getting crapped on by everybody in that chain and aren't being paid enough to care about doing things right if it just means getting crapped on by everybody who SHOULD care about the quality of the work...unless I am frequenting the site to see it happening and put a stop to it all. That SHOULD be the foreman's job, but they only care when an inspection is failed. That's not the product's fault. It's the whole chain, from the top down.
Dirk,
Congratulations for having the extreme patience required to make a site-built air gap around your ductwork. I still stand behind my earlier statement: "Most HVAC contractors are likely to consider the construction of a three-dimensional site-built air space around installed ductwork to be labor-intensive and awkward, especially considering the difficulties of working around hanger straps. Moreover, the R-value of the assembly depends on the long-term maintenance of the 3/4-inch air space; if the Reflectix ever sags, the R-value of the assembly will drop."
If an installer can create such an air space, and if it can be maintained without sagging, the foil-faced bubble wrap plus the air space will indeed insulate the ducts -- although there will, of course, be thermal bridging at every location where spacers were inserted to maintain the air space.
Most installers agree that it's easier to install insulation than to create such a delicate air space.
Thermal bridging will be minimal if the proper materials are used to make the spacers.
that photo of the dripping duct is a fraud. anyone who runs 65* temp at the t-stat will create many problems.
Following his WWII demobilization, Farley Mowat was sent to the Canadian arctic to study the diet of wolves. Observing that they seemed to survive primarily on small rodents, he conducted his own first-person study of the efficacy of a field mouse diet by eating nothing but (this was the true background story behind his famous novel and movie Never Cry Wolf).
When he explained his strange dietary preference to the local Inuit who kept an eye on him to make sure the "stupid one" didn't do himself in, they politely responded "Good idea".
What do I think of bubble foil duct insulation? "Good idea".
I am having a home built. I want to install insulation on the outside of the home. I was planning to have 0.5 inch rigid foam insulation installed, but my framer stated he can get radiant bubble insulation. He said he normally installs this under metal roofs, but it would be as good as R value wise as 0.5 inch rigid foam. Is this true? Are there any issues with using it as an outside wall insulation method? The walls are OSB with house wrap, and we will have vinyl siding.
how about we try to come up with some truths instead of trying to bash one side or the other?
--space suits... truly, if the stuff is snake oil, then why does NASA use it?
--proper application... so, if it's not good for all applications, then how about telling us which it is good or bad for?
Chris,
One half inch of foam will have an R-value of R-2 to R-2.5, depending on what foam you use -- not much. If you want to install insulation on the exterior side of your wall sheathing, you need to be sure that the insulation has a high enough R-value to avoid problems with wall condensation. The minimum R-value of this exterior insulation varies with climate, but is higher than R-2 in all but the hottest climates.
If you tell us where you live, we can tell you how thick your foam should be.
In all climates in the U.S., foil-faced bubble wrap costs more per unit of R-value than foam, and is therefore a waste of money.
Well first off the most important step as has already been noted is sealing the ducts properly and you will already save energy over poorly installed and unsealed ducts as are found in many older homes (I have even seen exterior stud bays with a single side of metal with the uninsulated outside wall used as a duct in some older homes that is the most extreme case of poor installations I have seen) But the fact is radiant heat gain and loss is real but it is not the primary loss. R-Value is real.
To really test this you only need look at the Low E-GLass window vs standard glass.
The R-Value of the two pains of glass with a sealed air space is the same but Radiant heat transfer is much lower with the low-e glass.
But even a minimal insulated 2x4 wall retains more heat then even the best glass window. if you want a well insulated home keep the windows on the North side small.
Re: Foil faced bubble wrap - I used it on a wall in a 17 story building with two marine boilers powering an absorbtion cooling system, which means it's on more in the summer than winter, the chimney wall was uninsulated and a thermometer taped to it read 120 degrees. I put in the foil faced bubble wrap then 1 1/2 inch studs with some fiberglass between them. The wall temp is now about 85 on the hottest days. While I don't have the math handy, I resorted to bubble wrap to avoid loosing many inches of space from the adjacent kitchen trying to beat the heat with just fiberglass, and foam in a hot enviornment, can you say "outgassing", not to mention accelerated aging. So I think radiant barriers do have uses, and if it's attached to bubble wrap, it's just a little bit extra.
Re: Wrapping duct in bubble wrap. I can think of an attic or two where I'd rather wrap that around a half dozen times than try to deal with fiberglass all over me, and, having asthma, mold is a big concern, and the one commentator is certainly right, fiberglass makes a great mold home, bubble wrap does not, and radiant heat in some attic spaces in the summer is INTENSE.
Moral of the story I think is that the answer is - IT DEPENDS - not just on pure R values, or emmisstivity, or condensation, or installation. No material or technique is a cure all in construction, you always need to be thinking, to be adaptable.
Chris When I built my house I used 3/8 foil faced fan-fold insulation than put wood lath on 16 centers and hung metal siding. Tape the seams and it will qualify as a weather protective barrier.Run it into overhang to vent into attic. It sure helps keep my home cooler in summer.
Thanks Stan
Just a note here. No science. Layman understanding. I am a sales consultant for a frim which sells LOW-E coated windows (radiant barrier/non vapor barrier), Blown in attic insulation (fiberglass) and not bubble wrap but a foil radiant barrier and a spray on radiant barrier. I have a display of the foil radiant barrier - one side with just r-11 bat insulation and one side with same insulation and the foil radiant barrier. There is typically a 35 - 45 degree difference in the temp. below the fiberglass insulation.
My understanding. R valued insulation slows down the transfer of heat and stores it untill it can disipate it. R values I believe are determined in an environment of 75 degrees. Radiant barriers reflect the radiant heat (not conductive) back so it does not enter the space. Both are used for different purposes and should not be comaired to each other but should be used with each other. I always sell them both together.
Martin Halliday: What is a GBA advisor?
Use the product in a proper combination.
I added the bubble wrap radiant barrier to existing R-6 duct insulation and around the attic-based air handler. Additionally, I added a radiant heat barrier to the underside of my rafters running from the soffit vents to the ridge vent.
Energy savings:
July, 2007 (prior to radiant barrier) Avg Daily Use 125Kwh - Avg Temp 75
July, 2008 (after radiant barrier) Avg Daily Use 70.9Kwh - Avg Temp 75
That's a 43% savings.
In 2009 I added a programmable thermostat witht he following results:
July, 2009 (after thermostat) Avg Daily Use 58.2Kwh - Avg Temp 73
Thermostat set to 77 in the heat of the day and 73 at night for comfortable sleep
Granted there's a avg temp reduction but there another 18% savings
The payback for the radiant heat project was realized in a single year. Use the radiant products as intended and they perform extremely well especially given their relatively low cost.
Jerry,
"Green Building Advisor" is the name of this Web site. The term "advisors" is also applied to a group of experts who contribute to the site and help answer technical questions. (Editors are included in our list of advisors.)
More information is available here:
https://www.greenbuildingadvisor.com/our-advisors
Michael,
Anecdotal data is at best instructive but not necessarily meaningful. Your energy consumption figures tell us little unless you relate them to cooling degree days to normalize for variations in summer weather from year to year. Perhaps July 2008 was not as warm as July 2007. And how did July 2009 compare to the previous two?
Yes, radiant barriers work to control summertime radiant heat gain, if installed properly. Insulation works far better in controlling wintertime heat loss. Air barriers work to minimize convective losses and condensation problems. Each has its proper application and its proper methods of installation. And each are widely misunderstood, with radiant barriers (esp. bubble foil) being so overhyped that the FTC had to step in years ago to stop the worst of it.
As for Energy Star approval:
The U.S. Federal Trade Commission (FTC) defines "home insulation" as "any material mainly used to slow down heat flow" (16 CFR Part 460.2). ENERGY STAR considers insulation to be products or materials that meet the FTC's definition of "home insulation" and are used to insulate a whole wall, ceiling, or floor. These products include, but are not limited to: fiberglass, cellulose, mineral wool, whole-wall spray foam, rigid foam board, cotton fiber batts, and foil radiant barrier products.
The following information must be provided for each product that the manufacturer wishes to be considered for the ENERGY STAR mark:
R-value lab test results (or emissivity results for radiant barrier products), as required by U.S. FTC "home insulation" regulations (16 CFR Part 460).
Consumer materials explaining what the product is, what it does, and documentation of claimed energy saving benefits.
Clear instructions for proper installation of the product to get the benefits promoted by the manufacturer.
First off, I am not in the trades. I'm an IT guy. However every spring as the air space between our dropped ceiling in our server room and the actual roof of the building would warm up, the cold duct work (the server room AC runs 24x7) would start condensing real bad and over a single weekend I would end up with large amounts of water spot damage on the ceiling tiles and sometimes even a dripping leak. Our HVAC guys came in and wrapped the ductwork with what I believe to be the topic here. It was silver stuff that looked and popped like bubble wrap. Ever since wrapping it we've had no condensation problems anymore.
I can't speak to R value or anything other than it provided what was necessary for the application we needed it for.
It's a scam, just like the toilet paper oil filters, the oil additives that increase gas mileage, etc., etc.
But as with all of those, the bubble wrap insulation will have angry defenders.
Additives CAN increase your fuel mileage, under the right conditions. Not necessarily oil additives, but if you have injectors partially clogged because you use too much of that crappy AM PM gas and are dripping instead of atomizing a few tanks of a good injector cleaner will take care of that problem and you'll get a couple miles per gallon back.
Many oil additives are of the snake variety. That being said, changing your oil on time and using the RIGHT additives can extend your engine's life by 30% or so. Additives including Zinc, for instance, actually do a LOT to keep your cams and crank in good shape. Before you call me an "angry defender", my knowledge is from countless teardowns for failure analysis early in my engineering career. You could tell who was using what by looking at wear, doing oil analysis, and such.
This product, if used properly, works pretty well. It takes a level of care, understanding and exactitude that most people, even those who should because it's their job, don't want to take the time to do it right.
I have a 1964 ranch style house that was built using 2 inch fiberglass insulation in the garage ceiling. Part of my supply and return lines run through an unconditioned garage to feed the 2 bedrooms that are above the garage. When the a/c is run in the summer, the condensation is severe enough to cause dampness and mold on the garage ceiling drywall. I have ripped out the old drywall, and I'm in the process of sealing the ducts with mastic and was going to use foil/fiberglass to wrap the ducts and then insulate the ceiling with R30 fiberglass. Should this type of duct wrap product still be used in a high humidity environment or is there something better? The ceiling is still open so I can still make any changes if needed. Thanks in advance.
It's not a scam, but it has limited value and only when used in the appropriate applications.
As the IT man pointed out, it is an excellent vapor barrier (if seams are well-taped) and might raise the surface temperature just enough to eliminate condensation in certain situations. But it certainly doesn't meet the IECC R-8 duct insulation requirements for unconditioned spaces.
It isn't the temperature rising. The product, if properly sealed, keeps the moist air away from the cold surface and, if that much condensation was actually occuring, you aren't talking about "raising the surface temperature just enough...". There would have to be a considerable temperature difference. Do I need to tell you how much heat has to be pulled out of water in the air for a phase change from gas to liquid to occur at all, let alone at that level? To go from water stains on the ceiling to dry, that's a considerable amount of radiant heat energy that bubble wrap foil kept from being absorbed through it's outer layer.
I use this product to wrap our above ground sewer and water lines for our relocatable remote camps up north. We also use heat tracing taped to the pipe and then wrapped with bubble wrap. The temperature drops down to -50 celcius. I think we are using the product to reflect the heat and keep it on the pipe more so than keeping the cold from freezing the pipes. We are currently looking at alternative ways to insulate our pipes both on a temporary (one season) to permanent (1-10years) application, both still above ground.
Any suggestions? Are we using this product properly?
Keith,
Use foam pipe insulation instead. If the pipes are exposed to the weather, protect the pipe insulation with aluminum-faced butyl tape (for weather protection, not insulation).
Artie Enj,
If you need to insulate your ducts, use duct insulation, not bubble wrap.
1964 Ranch House-retrofit: I've used a radiant barrier and duct insulation in DIFFERENT applications.
The problem is air movement from the hot, humid garage to the cold ductwork-mastic and sealing those ducts well is vital.
For air conditioning, condensation is a big issue. Making sure the duct work is sealed with mastic and, if possible, runs INSIDE the conditioned space by building an insulated chase is the best approach.
For a quick fix, you could try the radiant barrier, and make sure it is sealed/taped tight. But I think replacing the ducts with pre-manufactured, insulated ducts and enclosing them in an insulated chase is the best way to go, and even then I would prefer to use foamed-in insulation rather than fiberglass.
I anyone has read down this far and still thinks bubble wrap is decent insulation, then you deserve to live in the crap you build - or have your former customers coming after you 5 years down the road after it fails, possibly causing damage to their houses. Whatever happened to common sense?
There is no free lunch and no secret to reflective insulation - it works well in a vacuum and will give you the equivalent of a little less than R-1 under the best of conditions on earth.
Yes, radiant barriers are a good deal in the desert and very hot areas, but are a waste of money in cooler areas.
So lets give it a rest and if some idiot wants to save a buck - fools rush in. I'm sticking with fiberglass and foam on my projects - and I'll pay for my own lunch
My problem, that this stuff fixed for me was that, due to the humid coastal air, the fiberglass in my crawlspace was getting saturated with moisture, ESPECIALLY when the temps started to drop below the dew point...even with a vapor barrier. Wet fiberglass doesn't insulate. It wicks heat away, through the floors. It also says, gets moldy, and after enough time, the jousts start to rot. When I ripped all that crap and PROPERLY put this stuff in, I had to first rip up my floor, pull out sections of joists, sister them to new wood, then put it all back together again. No, by the way, there was no plumbing in the areas I had to repair. Apparently, when some plumbing repair was done, they tore out the insulation and failed to replace it. Long story short, this stuff is doing great. You just need to make sure you have the proper air gaps, tape it properly, don't skimp on staples, and have the right number of the proper size of air gaps. I have three layers, properly spaced and my electric bill dropped so much the electric company came out to check to see that the meter was working properly and that I wasn't tampering with it.
When I first left home at age 17 and ventured out to the Colorado Rockies, I had nothing but a canvas pup tent and a cotton sleeping bag. So I bought one of the new "space blankets" that promised to reflect body heat back at you.
The first night I camped along a mountain road, I wrapped myself in the space blanket and slid into my sleeping bag. In the middle of the night, I awoke shivering in a puddle of my sweat. I've been skeptical about "radiant insulation" ever since.
Now that I've been designing, building and engineering for more than 30 years, I have a more thorough understanding of the physics of insulation, radiant barriers and vapor barriers. Radiant barriers have their applications (lowE windows, hot climate under-roof barriers, floor vapor/radiant barriers over a vented crawl space, and under radiant in-floor tubing), but are nearly useless in most other applications.
Umm... apparently the space blanket worked fairly well. You were soaked in sweat. Sweat (water) is one of the most effective heat transferrence mediums that we know of. Getting too hot in cold weather is worse than being uncomfortably cold and dry.
Robert,
Your post made me laugh. At age 17, I also bought a space blanket, and also shivered. I soon learned that thick down works better than thin foil -- a lesson that stuck with me.
To Martin Holladay, GBA Advisor - response of May 25 10
Your post is a collection of half truths and outright falsehoods. It would take too long to address them all. However, I'd recommend successfully completing a course in physics - especially since you infer you have such training.
Go look at the test process and the formula for determining R-value. It measures only conduction. It does NOT actually test convection except on a micro-scale within the insulation. Radiation is specifically precluded by the test method.
Go back to your claimed understanding of physics; doubling the thickness will double the insulation. If you double the thickness and plug that into the formula for R-value it will not double the R-value, but will yield less each time thickness is added. Go look up the word 'asymptotic' and you will know the mathmatical term for diminishing returns. End of story.
There's a good reason that foil-faced bubble wrap isn't considered "mainstream," as you put it. It is terribly expensive compared to glass.
And before you dismiss the references to the technology that allowed us to sucessfully send men into a very hostile situation unscathed, space, use some of that good old-fashioned physics (after you learn it, not before) and look long and hard at the importance of regulating radiated thermal energy.
Sometimes it seems that anyone can claim, without any merit other than that claim, to be a GBA, even Gomer's building assistant.
Berferdt,
You have no Idea what you are talking about.
Go put on your foil hat and drink some more Tang.
BERFERDT,
In outer space, heat transfer is by radiation alone, since there is no matter to allow conduction. Additionally, high levels of protection are required against the several other spectra of deadly radiation - hence "space blankets".
Clearly, you received far too high a dose of gamma radiation when you were there, and you seem to have left a good part of your gray matter in outer space.
ASTM C 177–04, “Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus”, ASTM C 518–04, “Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus”, ASTM C 1363–97, “Standard Test Method for the Thermal Performance of Building Assemblies by Means of a Hot Box Apparatus” and ASTM C 1114–00, “Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Thin-Heater Apparatus" are all methods for determining the steady state HEAT FLUX through an insulating medium.
All those FTC-approved test methods measure total HEAT FLUX through a material, excluding any adjacent air spaces (and hence eliminating the benefit of radiant or low emissivity surfaces. Such HEAT FLUX includes conduction, internal convection, and internal radiant transfer. Thus a double-pane lowE window is measured as R-3 rather than the R-2 of a clear double-pane window because there is less radiant transfer and less convection between the two panes of glass.
With a homogeneous insulating material hot-box rated at R-N/inch, the total installed R-value is always N times the number of inches of installed thickness. In other words, for those who are not asymptotically challenged (diminishing IQ with higher math), the installed R-value of insulation is directly proportionate to the installed thickness - double the thickness, double the R-value.
How good an understanding of physics do you need to realize what might be useful when exploring space and what might be useful in your basement are two very different things? Same thing with the emergency blanket thing - I don't need my home or duct insulation to be able to collapse into a convenient sized package. These things may sound impressive or reassuring but unless you consider all the different factors and how they apply to you & you're situation they're kind of meaningless.
To that end I'd be weary of anyone pushing those lines. Especially in the absence of real data & solid reason. Especially if they were trying to sell me something. Especially if that something was associated with an industry that has been known to make false/misleading claims and push snake oil type items. And especially if someone who's seems more intent on boring me than impressing me (no offence meant) is able to explain why that something is not the better option.
Berferdt,
You wrote that "Doubling the thickness will double the insulation. If you double the thickness and plug that into the formula for R-value it will not double the R-value." Ah, but it will.
Doubling the thickness of an insulation material will double the R-value and will cut the heat flow through the insulation in half.
It seems you are trying to refer to another issue: the fact that each time you double the thickness of the insulation, you save fewer BTUs. That doesn't mean that the insulation isn't working; it's working very well. It just means that as the heat flow gets smaller and smaller, each doubling of the insulation is addressing a smaller and smaller problem.
Here's an analogy: let's say BP puts a device on their blowout preventer that cuts the flow of oil out of their broken well. It costs a million dollars and cuts the flow of oil in half. That's great.
If the broken oil well is leaking 16,000 barrels of oil a day, now we're down to 8,000.
Let's say they keep putting more and more such devices on the wellhead. There's a wrinkle, however: each device costs twice as much as the previous device. (After all, doubling the thickness of a layer of insulation costs more each time you do it.) The second device -- the one that costs 2 million dollars -- cuts the flow to 4,000 barrels a day. The third device costs 4 million dollars and cuts the flow to 2,000 barrels a day. The fourth device costs 8 million dollars and cuts the flow to 1,000 barrels a day. And so on.
The fourteenth time that BP installs such a device, the device costs $8.192 billion and cuts flow from about 2 barrels a day to about 1 barrel a day.
Each time they install a new device, the result is the same: the flow is cut in half. But as the flow gets smaller, the investment gets more expensive and yields a smaller reduction in flow.
Martin. Please advise where BP can get these devices ASAP.
Ah, Robert Riversong, you quote an interesting source in limited context, cast unqualified aspersions, and in your zealous defence of a polar position seem to miss the whole point of review and comment.
Farley Mowat was sent into the arctic on what he described as a government fund wasting fiasco where there was government money to throw blindly into an opinion-driven, pseudo-science project. We did reap one of his books from the project; the only one most people have ever heard of because Disney never made any of the others into movies. The corallary between government funding of unscientific wolf-diet research and government funded unscientific (read: opinion-driven) 'green' projects is not lost on those less inclined to accuse others of being aficed with gamma poisoning or leaving grey matter in space just because a critical view of the material presented is offered.
You cite many standards from ASTM then proceed to make the same point I was offering. Thank you for that. The standards sited do not state there is either a benefit or penalty for a radiant barrier, in fact the E-value of a window is considered along side the R-value.
You use the term heat flux, all in caps, like it has more relevence that simply using the term conduction, but it is actually a proper term for conduction per unit area. No more, except in the case one is measuring radiated heat.
Please take this for what it is worth. I did not mean to impune you. If I did, I don't think I could have done a better job of that than you have already done to yourself by decrying those who are able to do higher math.
BERFERDT,
HEAT FLUX (which I capitalized so that you might notice the term) is a vector quantity which is the magnitude of energy flow per unit area per unit time. It is a unit that is independent of mode of transfer and hence includes them all.
Your ignorance of physics is matched only by your ignorance of simple algebra (2 x R = 2R), and it is just this intelligent-sounding but thoroughly incorrect BS (and that's not building science) which encourages people to accept the hype of the radiant barrier industry and which keeps this ridiculous thread going nowhere.
no
I might not be with the current insulation ratings, but about 30 years ago when I worked in R&D for a large fiberglass insulation company there were a lot of factors that went into the rating of a bat. The thickest bat that we could make at the time was an R28. And even this bat was very irregular in its rating. It achieved an overall R28, but you had areas of the bat that were less and more in R value. The difficulty is in how you lay down the glass fibers and how the bat recovered after being flattened. In order to achieve a higher R value we took 2 bats and glued them together. I can remember that we took 2 R20 bats and this became R38. It did not acheive R40.
Now this may not hold true for foam type insulation and you may very well get double the R value with double the amount of foam. But in reality the overall effective insulation will depend upon the amount of thermal bridging involved.
Bigfoot,
Thermal bridging is an entirely separate issue from the relationship between insulation thickness and R-value.
What you're describing is the change in compression of a fiberglass batt, which diminishes its installed R value. If you take two R-20 batts and install them together with no compression (and install them perfectly, which never happens with fiberglass), then you will get R-40.
With fiberglass batts, as much as 40% of the rated insulation value can be lost due to poor installation (which is the norm, particularly with paper-faced batts). That's why RESNET downrates fiberglass according to the quality of installation (grades I, II, and III).
Slightly off topic, I used some "insulating ceramic beads" for paint. I painted equal coats with and without beads on 7/16" OSB. I could not discern any temperature difference between either the front of back of the board when measured with my infrared thermometer after and during heating by the sun. I also mentioned the board after sitting against insulation. The bead side should have been cooler. It never was. The difference between white, tan and dark green paint was quite significant. As I recall, dark green was about 40-60 degrees F hotter than white. Tan was about 10-20 degrees hotter than white. Thus insulating beads are another snake oil. I do like the gritty appearance of the paint with beads, so I may buy another type on an auction site that has a low price and no claims of insulating ability.
I do a lot of work in 100 year plus homes with foil backed styrofoam, Roxul mineral insulation and double thick foil bubble wrap. I use these three materials together in different combinations. The reason I have chosen this method is due to the fact that I have had to tear out traditional materials pink FB due to mould. You may say that the reason for the mould was improper installation but in many cases it is impossible to install it in a 100% correct manner as this can ONLY be done in new construction.
I have over my 20 years in the restoration business decided it is far better to guarantee a mould free system than not .
Pink insulation is a moisture sponge and this is the primary reason we need to use a vapour barrier which is immediately perforated by drywall screws and any pictures or shelves hung on the wall.
In basement situations building codes in my area of CANADA allow you to use wood and even steel studs studs on exterior walls. They have not included the concept of either heat or moisture transfer through the studs. The codes have also not considered that these brick walls are uneven and create air pockets and create condensation issues which is absorbed by the wood studs and the pink FB creating a mould environment from the backside. By using foil backed 3/4 or 1 1/12 styrofoam first and then framing the wall I am isolating the framework and the insulation contained within. For basements I prefer to fill the 1 1/2"stud (on the flat)walls with styrofoam and top it off with a layer of bubble wrap and then screw 3/4 " strapping on top of it all creating the required air space.
This system is 100% vapour barrier over 1 3/4" thick. It allows 0% air flow and will not mould.
The drywall I use is fiberglass backed and mould resistant
If your basement ever floods it will shed all moisture and will not need to be replaced.
What most people on this post have failed to notice is that ANY failure in the flimsy 6mil vapour barrier compromises your system and introduces mould which is a huge health issue.
The other issue that has been overlooked is that without the vapour barrier the r value is greatly reduced. Batt insulation only slows down the air flow but does not stop it. Bubble wrap stops ALL air flow .
To put things in a more simple way would be the difference between a balloon made of thin rubber or a balloon made of a thick wool sweater to contain hot air or even a sweater without a wind breaker on a cold windy day
Once you start to look at insulation systems and building techniques in a different light there are far more ways to create healthy warm homes. Mould is a far bigger health concern than heating costs
and foil bubble wrap offers a healthy alternative.
Anonymous,
You can have the same results using inexpensive builder's foil (kraft paper backed foil) instead of over-priced and over-hyped bubble foil.
And by encapsulating your framing between two layers of foil, you're creating a potential for serious moisture problems. Double vapor barriers do little but trap moisture.
Robert,
I understand that thermal bridging is a separate issue, but you cannot discount it. I play’s into all final equations. Only a fool would think otherwise.
As for your insistence that doubling fiberglass batts results in double the insulation R factor you obviously don't know what you are talking about. Apparently you know more than the people that engineer and test this stuff. They don't rate it that way. Take a look at then Owens website and take a look at how different thickness of insulation results in different R value per inch. Perhaps you can use your superior math skills to calculate that. I worked in the industry developing the product and was involved in the testing. What you say is nonsense when it comes to fiberglass insulation. The compression of the product is a separate issue. Manufacturers do not rate their products based upon poor installation.
That is why nodulated (loose fill) fiberglass is such a joke. We developed that product because of line jams. When the line jams you cannot just shut down a glass furnace. You pull the product off the line and fix the problem. This created mountains of insulation that was unusable until we decided to chop it up and sell it as loose fill. It does not hold to any standard. It’s up to the installer to get the density right and even. With batts it’s another story. Each batt has to meet specific requirements. That is why with fiberglass 2 plus 2 does not equal 4. But you could always round up.
Unfortunately you are not satisfied with that, so you go ahead and tell all of your clients a lie. The facts and test do not lie, no matter how much you want it to be otherwise. And I am sure you will also come back to this post with some other nonsense of a reply. Your reputation is only diminishing.
Oh, by the way who in world uses batts with paper? That went out with disco.
Bigfoot, looking at that exchange you seem to be misinterpreting Riversong's posts. He did specifically state that fiberglass installations are never perfect and in that imperfection their R-value is diminished. You should understand that he's talking theory about a specific subject and that subject is "the relationship between insulation thickness and R-value" and not "actual r value of specific type of wall assembly". I don't see him insisting that, in the context of fiberglass batts doubling thickness = doubling R value, but instead is just referring to the principle that that's how it generally works.
That might seem dead wrong to you thinking in the context of fiberglass, but fiberglass is probably more the exception than the rule. The hint there is that, as you mentioned, manufacturers of batt insulation tend to state r value per specific type of batt (ie: that particular batt's thickness). If you look at specs or discussions on foam it's R value is pretty consistently stated in R per inch.
Where you might harp on him b/c his argument seems wrong in the context of fiberglass consider how what you're saying works in the context of other assemblies. ex: What does thermal bridging mean to the person considering the thickness of foam boards to sheath their exterior walls with, how thick of SIPs they should go with, or how much spray foam they should apply to the interior concrete walls of their basement?
That's why it's important to stay concise when trying to explain principles. There may be a lot of other considerations but they don't necessarily apply to everyone or even the immediate point. To that end, to assume omission of those other considerations equates to ignorance is faulty logic.
Ok, here, you're partially correct. When you double the thickness by doubling the material, you double the R value. The problems with the irregularities in the R level have (at least, initially), largely, to do with the way that batt was installed. People crush the batt while they're installing it. The shove it in, put staples right through the center of the batt, anchoring it to sheathing, etc. If fiberglass Batts were all constructed to be a standard width, had a more solid backing that didn't tear easily, construction crews were more careful about simply sliding it into place instead of manhandling it, and the staples were placed through the folded lips of the backing, into the stud, you could then probably put in a second layer in the same fashion and come extremely close to doubling the R value. The same thing is true about radiant barriers and layered large (gap) and small (bubbles) air gaps.
Regardless of how Big a Foot Bigfoot puts in his mouth (don't you love anonymous posters who can say anything they want with no responsibility?), putting two R-19 batts together produces R-38 insulation, all things being equal.
What builders and installers and even fiberglass hucksters have long misunderstood is the relationship between density and R-value. It used to be commonly thought that compressing a fiberglass batt into a smaller cavity decreased the R-value. While it's true that the labeled R-value of the full thickness batt will diminish, the R/inch will increase. It is, in fact, on this basis that manufacturers were able to produce an R-13 batt with the same thickness as the old R-11 batts - simply by increasing the density.
Forcing an R-19 batt, for instance, into a 2x4 wall cavity, will produce an R-13 batt with R-3.7/inch instead of the manufactured R-3.3/inch. But doubling the thickness of fiberglass batting in a wall cavity will always double the R-value if no compression occurs, no matter how big your foot.
I'm presently installing pex tubing for radiant floor heating between the floor joist of my first floor which is above a full basement. The pex will be suspended some 3" below the above subfloor. The supplier for the pex (and the heating plant itself) also sold me foil faced bubble wrap to be installed beneath the pex. The purpose of the foil wrap is to create a 3" reflective air space directing the trapped radiant heat up towards the floor of the living space above. I plan to not only staple the bubble wrap in place, but to also use strips or wooden lath to insure a seal along the edges of the wrap against the joists. Will this be an effective insulator/air space, directing the heat to the living space above?
Anony Mouse,
Unless the basement is unheated, there's no need to batten down the bubble foil.
Yes, this is one of the few good uses for bubble foil. But I would advise placing the PEX 2" below the subfloor and the bubble foil 2" below that, for a 4" radiant air space which will not only direct the radiant heat upwards but also create an effective R-8 barrier between the first floor and the basement.
I think Martin is right. let me tell you my real experience. My contractor use Reflectix bubble wrap product for my ductwork in attic. The cooling deteriorate when temperature goes up in this summer. My AC kept running but it could not cool down my upper level. This product definitely does not work well and I don't trust its R value. I asked my contractor to replace existing ductworks with other insulation material to achieve better result.
Anony Mouse,
Unless you come up with a legit name, I'm going to spring my anony-mouse trap on your and wrap you in bubble foil until you sweat.
Each of us was born with a name. Why some people are afraid to use theirs is beyond me. Must be hiding from something.
Come out of the closet or keep the door shut.
Do you guys have experiance with EcoLift bubble wrap and its method of installation?
I am an consultant and work for food industry. My client is strongly advising to use duct bubble wrap for RA duct and SA duct in the process and non-process area just because it is cheap and quick to install. I am evaluating their specs and modfying their standard specifications.
Hardik Shah,
I will repeat a statement I made in my first response to this question: "The claim that bubble wrap is equivalent to R-6 duct insulation is a scam and a fraud."
C'mon, everybody. Stay away from the bubble wrap. If you want to insulate your ducts, use insulation!
Why would you use foil faced duct wrap insulation? Isn't the foil supposed to reflect radiant to the warm side, and requires an air space? Or are you assuming a primarily southern air-conditioned situation?
It seems to me the ducts should be sealed first, and then insulated depending on climate, and to some degree depending on location of ducts (ie in a heated/conditioned space or not). Does code require a ducts through interior walls to be R6? Regardless, any ducts in an unheated space would do well to be well sealed, and have more than R6.
That's a common misnomer. Cold doesn't radiate. Heat does. Heat is simply kinetic energy (motion) on a molecular scale. This is still an oversimplification, but he cold absorbs the heat...meaning fast moving molecules smack into slower moving ones, slowing down the fast moving one, but causing the slower one to bounce off at a higher speed. You want to keep the heat out of your ducts when your AC is blowing and keep the heat inside the duct while the heater is blowing. The wrap, with two foils is designed to do that, but simply wrapping your duct like you're taping up a cracked rib isn't going to work very well. You need a gap of at least 3/4" and probably no more than a couple inches, but I don't want to run the math again and don't remember the manufacturer's spec.
Dan,
The foil serves as a near-perfect vapor barrier to prevent condensation on cold AC ducts.
And a radiant barrier doesn't reflect IR radiation, though foil obviously reflects visible light. A radiant barrier requires a lowE surface facing air (not an air space). A lowE surface has low IR absorptivity as well as low IR emissivity, so it doesn't emit much of the heat of warm air ducts and doesn't absorb much radiant energy from its environment when covering cold air ducts.
Aluminum reflects at 95% WELL into the IR spectrum.
HI Lora-
We have been installing our ducts with reflective bubble wrap for 4 years now. The actual R-value for the wrap is 4.2. We use a single wrap for all duct that is located in conditioned space. If it going into unconditioned space we double wrap it and we use spacers between the layers to obtain an R-8. This is qualified for energy star efficiency and it works great. The best thing is that it does not have fiberglass in the product so there is not an intrusion into the heating system in any way by fibers that could be floating around. There are some towns that don't allow this install and they want the FSK wrap which does not achieve as high an R-value. Our company has done hundreds of installs with the reflective wrap, we even have it here in our office if you are ever interested in seeing what the end product looks like.
Melissa,
If you've done "hundreds of installs" of bubble foil duct wrap, then you are truly an amazing scam artist.
Bubble/foil manufacturer's claim as much as R-14.3, but the tested R-value for typical product is R-0.67. If installed with an air gap between it and the duct, it can offer very modest R-value but not what you're claiming, and few installations use the required spacers.
Two layers with a 3/4" space can offer as much as R-3, but only if the space is permanently maintained.
Melissa,
I don't know what type of foil-faced bubble wrap you are using, but I have never found one with an R-value as high as you claim (R-4.2). According to ASTM C518 tests commissioned by Reflectix, the product has an R-value of 1.04.
It is my understanding that the foil is reflecting long IR which is the heat we want to retain in a heating duct or heated building. Visible light is irrelevant. I have conducted black body tests with a Fluke TIR thermal imager and foil bubble insulation with different materials covering it such as tyvek and cotton cloth with and without air gaps and it blocks significant heat transfer from the heated black body in all tests I have conducted. Oakridge National Labs has recommended to me a 3/8" air gap for optimal utility of foil insulation.
Prodex is a polypropylene foam core rather than bubble core and has a reported higher insulation value.
Foil bubble material is used successfully for commercial shipping of cold shipments and is manufactured to fit specific sized shipping boxes.
Clearly these foil insulation materials have merit beyond their use in outer space in many applications requiring insulation.
Sally,
No one has claimed that bubble foil has no merit, but it has long been advertised with outrageous and poorly-defined claims of insulation effectiveness, without the required caveats for poor installation or comparison to other materials, and even marketed for applications (such as sub-slab insulation) for which they have no value as insulation.
Simple builder's foil works as well as a radiant barrier, and is much less expensive. The bubble or foam core adds no more than R-1 of insulating value, though it also offers some rigidity making it more useful as duct wrap.
But, to function as duct wrap, it must maintain an air gap between the foil and the duct or it becomes nothing more than an R-1 wrap. With double gap applications (two layers of bubble foil and spacers), the two gaps must be pneumatically isolated or convective currents will reduce the effectiveness to almost nothing. And the gaps must remain undisturbed for the life of the installation (not likely with exposed ducts in a basement).
Additionally, the initial emissivity of 0.05 may quickly degrade due to aging, oxidation, dust or pollutant contamination. Even with a light condensation coating, the emissivity can increase to 0.3.
Radiant barriers are most effective in hot-climate roofs and in radiant wood-framed floors, as long as they can be protected from dust accumulation.
They are also very useful for astronaut suits and wildland firefighter emergency shelters for their ability to dramatically reduce high-intensity radiant energy transfer. Bubble foil may be useful for packaging because it's light, takes up little space, and offers some minimal insulating value.
But most of the bubble foil marketing is shear hype.
The ASHRAE Handbook of Fundamentals states, “Values for foil insulation products supplied by manufacturers must also be used with caution because they apply only to systems that are identical to the configuration in which the product was tested.” And actual tested installations never meet the claimed values.
It's amazing that this thread keeps re-animating like the walking un-dead.
But I suppose it's proof of the old aphorism: "There's a sucker born every minute" often credited to P. T. Barnum.
And the aphorism must be true because, by all credible accounts, Barnum never said it.
But it could just as well have been said by the creator of mass marketing (public relations), Edward Bernays, the nephew of Sigmund Freud, who used his uncle's theories of the unconscious along with Pavlov's theories of conditioning in his seminal book, aptly titled Propaganda (1928).
"If we understand the mechanism and motives of the group mind, it is now possible to control and regiment the masses according to our will without them knowing it."
Fiberglass insulation is a known Carcinogen, Bubble Wrap is not.
Fiberglass insulation grows mold, Bubble wrap does not.
Fiberglass is loved by Rodents, Bubble wrap not.
Fiberglass gets wet it's garbage, Bubble wrap will still be good.
Fiberglass deterierates over time, Bubble wrap does not
Fiberglass is always installed too tight and therfore loses it's r-value.
We have gone back on jobs we installed Bubble wrap on 9 years ago and it still looks the same.
The fiberglass jobs are a mess from moisture and Rodents.
We don't have all the sientific answers to many questions.
All I know is we have used it in over 3,000 duct applications in both attics and crawl spaces here in the Northeast New York with never one single issue.
That should count for something!
It works great, and I for one do not have to know why.
Dear Rat,
"We have gone back on jobs we installed Bubble wrap on 9 years ago and it still looks the same."
Yup. It looks like some fool wrapped the ducts in bubble wrap.
Chris, about 25 years ago I built my own 2100sq ft home in the tundra of Wisconsin (I still live in it). Instead of using 1/2" rigid foam on the exterior over the sheating, I used 1" (foil-backed both side) rigid foam insulation on the interior side of the exterior walls and taped the joints. Then sheet rocked over it. The wall studs were 6" which I used R-19 fiberglass. Then plywood on the exterior. It took extra work for the electrical boxes to be brought out that extra inch. I got my home so tight I eventually installed a HRV to rid of the humidity. But, the home stays warm and cozy in the winter.
There is no tundra in Wisconsin, unless you're referring to the Wisconsin Glaciation of 30,000 to 10,000 years ago.
I believe the Eskimos relied on bubble wrap, however, to keep their igloos warm. But they got no Energy Star credit for it.
Robert, just being in Wis is cold (bad) enough in the winter time. So far I haven't had any problems with my bungalow other than the many years of fighting the humidity until last year.
Just a note, in the installation of the HRV, some of the duct work for the fresh air intake and stale exhaust going to the outside was rigid metal insulated with R-4 Reflectix foil back foam followed with flexible duct to the outside wall. It worked for me.
I have put in many radiant floor systems under slab and under frame. Under slabs I have used both 2" foam board and on others I have used PBBF wrap. In my opinion only bases on using the products the bubble wrap is a more superior product to place under when compaction of the product is concerned basically due to if laying down to the subgrade better than something rigid. In the insulation side of the argument I refer back to my customers and there energy costs per job and application. Anything in a basement ( bubble wrap without argument) anything like a garage it seems costs are higher in units with bubble wrap but it could be inconclusive because of total heat loss when doors are opened in that setting. I am not an engineer and make fun of that but I am experienced contractor so as far as the actual r values vs K values or any other figure goes this sums it up liars figure and figures lie as a banker once explained.
That certainly says it all.
Let's hope most readers will find it easy enough to understand the arguments against bubble wrap, as they have been written in clear and unambiguous language (which also reflects a clarity of thinking).
Thanks to all for a lively and informative discussion. I'd heard that there was controversy surrounding the bubble foil and now I know the details. Based on the information gleaned here and my year of university physics, I"ll be using foil-covered foam sheets in the crawl space rather than bubble foil. Interesting that a search for information on insulation would bring back a controversy from my graduate school days more than 40 years ago. It was widely know among Canadian wildlife science researchers that Farley Mowat got his ideas about wolf diets from the earlier work of Adolph Murie in Alaska not from his short 50 hours of field research, but never credited Murie. Mowat made a lot of money and was briefly in the public spotlight but Murie work is still highly regarded among scientists.
From bubble wrap to wolves.
Yes, it's true that the wildlife biologists and (Canadian) federal agencies that Farley Mowat sharply criticized in his book turned the tables on him and tore into his observations and conclusions, even alleging plagiarism.
But it's undeniably true that Mowat did more to rehabilitate the age-old European mythology about the Big Bad Wolf and to promote wolf conservation (and later for whales and other species) than any scientist.
Excerpts from "Never Cry Wolf: Science, Sentiment, and the Literary Rehabilitation of Canis Lupus" by Karen Jones, 2001:
In March 1947 Mowat signed up for an expedition to Keewatin with an American ornithologist working for the Arctic Institute, and he revisited the area in 1948-9 as a student biologist under contract to study caribou with the newly created Dominion (later Canadian) Wildlife Service.
When Mowat published Never Cry Wolf in 1963, his estrangement from Canada's professional wildlife authorities was obvious. The naturalist had transformed his field observations of a wolf pack at Nueltin Lake in 1948-9 into an imaginative literary plea for canine preservation
The wilderness journey of Never Cry Wolf represented a route to self-discovery, a conversion project that involved the discarding of hoary preconceptions about bloodthirsty wolves. Captivated by the activities of the pack at "Wolf House Bay," Mowat offered his readers a startling epiphany: "Inescapably, the realization was being borne in upon my preconditioned mind that the centuries-old and universally accepted human concept of wolf characteristics was a palpable lie."
Mowat presented his lupine compatriots as a tightly knit, convivial community of mesmerising, albeit anthropomorphic characters. Crucially, amid the jocular anecdotes, Mowat forged a vivid impression of the northern landscape, its wolves and its people, as a vibrant, pristine, and, above all, moral society.
Mowat learned to see wolves as worthy members of the Arctic ecosystem. Never Cry Wolf disseminated a powerful, alternative narrative on Canis lupus. Mowat presented wolves as ingenious creatures engaged in a nutually beneficial relationship with the caribou.
In a 2001 article of The Canadian Historical Review entitled Never Cry Wolf: Science, Sentiment, and the Literary Rehabilitation of Canis Lupus, Karen Jones lauded the work as "an important chapter in the history of Canadian environmentalism."
Never Cry Wolf...sits within a North American nature writing tradition that encompasses works by literary greats such as Henry David Thoreau, John Muir...and Ernest Thompson Seton. Communion with nature, geographical and personal exploration, and a mystical sense of the environment as a moral and beneficent realm denote elemental themes in this naturalist vernacular....
At the same time, Never Cry Wolf participated in the birth of a new environmental revolution. Mowat's text represented part of an emerging discourse on animal rights and human wrongs that characterized the Canadian environmental movement in the 1960s. The storytelling naturalist incorporated his personal foray to the North into a truly modern, activist discourse on human relations with nature.
I live in the Nashville, TN area. My house is on a 3' crawlspace and the supply and return for my heat pump run through it. The crawlspace is not insulated and there is no vapor barrier installed on the ground. The main supply trunk is round (16" diameter I believe) and has a thin insulation wrap on it that is in terrible shape. During the summer I get a great deal of condensation forming on the outside surface of the main trunc. I've already replaced the return air duct with 16" flex (R-6) and nearly all the supply lines have been changed to 6" flex (R-8). My questions are: 1) What should be my order of operation in the crawlspace to realize the most savings (i.e. start with vapor barrier, then insulate crawlspace, then duct work or what?)? 2) What should I insulate the main supply trunc with? I thought I was going to use Reflectix (R) until I found this site.
Matt repost your question as a separate thread. Good questions... you should get good answers. Starting point is to deal with moisture.
Can we all agree that "bubble wrap" is an obscenity and mentioning it violates the 'terms of use"?
No, but calling your self the Doctor's wife is... Seriously speaking, though, this is why this thread kept reanimating over and over. Thinks needed to be set straight. There are people who say bubble wrap is like Frank's hot sauce--put it on everything. There are others, like yourself, who say the product is obscenity. I'm expecting low education on both sides, but then you claim bonafides and make derpty doo statements like, no, Aluminum doesn't even reflect IR... I signed up and your statements inspired your name. Both sides are 100% wrong.
The truth is, and you started to admit it several times but then started derping again, that this is a wonderful product that can do some pretty cool stuff and, if used for the right applications AND installed properly (which, if people can't get fiberglass done right...), it actually CAN achieve a fairly high R value. There are other things it isn't very good at unless you put a LOT of work into it to achieve something only marginally better, if that, than cheaper, easier solutions. Almost everybody on this thread, when I started reading were instances in which the fact that they had a computer and Internet access was an obscenity.
Derpy-Doo,
Any chance you could tone down the insults - especially when you are directing them at people who haven't posted here in well over a decade?