Green Building Forum - Multifoil Insulation

Multifoil Insulation

Tony Reed — Thu, 22 Jul 2010 12:34:38 +0100

Posted By: fostertom
Posted By: Mike Georgethe original in-situ tests carried out by Actis et al showed multifoil in such a good light largely because of the superior air tightness of multifoil over mineral wool
Can't be, Mike. Actis' Tri-Iso 9 was (like today's Tri-Iso 10) held together with quilt through-stiching. If you add up the area of the stitch holes (which are not blocked by the thread), it's equiv (if I remember) to a 70x70mm clear hole to every m2. Tri-Iso, like most multifoils, is incapable of being airtight. If you hold a bit to your mouth you can breathe through it with no effort!

Posted By: Mike Georgethere seem to be very few peer rieviewed publications looking specifically at heat loss through multifoil. If all of this were so easilly explained then why is that?
I think, and I'd have thought you'd know too, that Paul Mitton and the CMM were keeping their data and results non-public because involved in delicate negotiation with the testing houses, against powerful opposition from the conventional insulation manufs. Since CMM seem to have accepted political defeat, who's going to bother to publish stuff that just might be needed to a fresh attempt sometime?

Posted By: sainta ridiculously naive and cheap test carried out by a manufacturer who was singularly ignorant of the installation techniques of the very competitive materials they were intending to malign
Who sez? Can you substantiate that?

Guys,

You are correct about the stitching issue in varying degrees according to the product in question, the stitching also effects considerably the thermal performance of the product due to the thermal bridging, YBS have done considerable research into this area and have been extremely successful in creating an air tight vapour barrier product that has no stitching or thermal bridges hence a HOTBOX (and not Guarded hot plate) tested R value in a single layer roof application of 2.71m2K/W (including airspaces) also 2.44 m2K/W in a wall and 4.14 m2K/W in a floor.

With the stitching and the multiple compressions of 99% of the products on the market make it impossible for them to be tested accurately in a Hotbox as the material being tested is required to be a uniform thickness.

YBS's patented fastening system on the product allows testing in a hotbox under the EN standard as it is a uniform thickness.

In addition, the product has a Vapour Transmission figure of u = 58.000[-] to EN 12572 and is practically without being able to measure the difference 100% airtight.

Importantly..Paul Mitton has not been a member of the CMM for some considerable time 1-2 years and is in no way involved or connected with the CMM.

On the CMM, As the President of the CMM I can advise you that we have in no way accepted political defeat, we have been working very hard to establish an accepted and unarguable standard for testing and certification at European level tirelessly, we have also funded and completed an entire testing program incorporating insitu testing over a one year (four season) period in conjunction with LAB testing and computer modelling.

The CMM are now a liaison member as a European confederation to TC89 and to WG13.
WG13 is an official working group that has been set up after the failure of actis's WS36 to create an EN standard under CEN that will finally cover any questions that may be levelled at multifoil as a product.

All of the scientific data that has been produced by the CMM through notified and trusted testing institutes has been submitted to TC89 and WG13 and this will hopefully prevent any attempt at smoke and mirrors from within the multifoil industry and curve balling from the rest of the insulation industry.

I would invite you to the YBS website to review the certification and documentation for Superquilt, this may answer a lot of questions for you and give you an idea of how I suspect things will be moving forward, this is not saying that all multifoils perform in the same way as there are many on the market and some havenâ€™t even got any foil in them.....there is a huge difference between an insulation quilt that has been manufactured for purpose under strict quality conditions and procedures to make sure every layer of every m2 is the same in emissivity, weight, thickness, performance, when compared to many other "me too" products that have no proof of consistent performance, repeatability and reliability.

Finally, I realise that there are one or two products now that have a degree of thermal testing or certification, in these cases, special attention should be paid to make sure that the calculation for low emissivity is the correct one and not the one intended for double glazing! As this gives a falsely high performance figure.

I realise there may be a question or two, I will respond if there are.

Regards

Tony Reed
President
CMM

Multifoil Insulation

fostertom — Thu, 22 Jul 2010 14:17:14 +0100

V good to have you here, Tony Reed.
For legibility, would you click the Edit button at top of your post, click the Html button below, and Save Changes.

Multifoil Insulation

biffvernon — Fri, 23 Jul 2010 08:23:24 +0100

Tony Reed> I realise there may be a question or two, I will respond if there are.

Will it keep my coffee warm?

(Hint: go to the very start of our multifoil discussions over four years ago http://www.biffvernon.freeserve.co.uk/insulation.htm )

Multifoil Insulation

WatchIt — Wed, 28 Jul 2010 10:17:02 +0100

I have had a look at the Superquilt website. Tony, you make a point on &amp;quot;HOTBOX (not Guarded hot plate)&amp;quot; yet your test report on Superquilt seems to be in a hot plate.

Then you said...
&amp;quot;With the stitching and the multiple compressions of 99% of the products on the market make it impossible for them to be tested accurately in a Hotbox as the material being tested is required to be a uniform thickness.&amp;quot;

Hold up, I thought the idea of a the hot box was to account for complex structures (such as compressions) and that it was the hot plate that was the simple 2 plates with one uniform thickness between them. It looks as though you have to 2 mixed up to me, unless of course i'm wrong?

Another point, I noticed the kimble tags thing on the website too, is this all the patented technology is?

Multifoil Insulation

RBean — Fri, 03 Sep 2010 17:32:10 +0100

If you're collecting published research on application of foils...this June 2010 NRC report and subsequent reports s/b in your libraries.

http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc53574.pdf

rb

Multifoil Insulation

biffvernon — Fri, 03 Sep 2010 22:20:35 +0100

Thanks but it's not really about multifoils - just the use of single foils on plasterboard and suchlike.

Multifoil Insulation

RBean — Sat, 04 Sep 2010 00:19:08 +0100

No problem...posted it due to this excerpt: "In future publications, the authors will describe the benchmarking of the present model against experimental data recently generated by an independent laboratory and applied to basement wall systems having multiple airspaces."

Don't know if 'multiple airspaces' will equate to multiple foils but I suspect it does...won't know until the future arrives.

rb

Multifoil Insulation

Canute — Sat, 04 Sep 2010 08:43:06 +0100

Good one RBean - look forward to that research, sounds close-ish to my planned install.

Multifoil Insulation

WatchIt — Fri, 22 Oct 2010 10:53:23 +0100

http://www.communities.gov.uk/publications/planningandbuilding/determination451238

well well...the debate takes another twist (against in-situ testing).

Multifoil Insulation

biffvernon — Sun, 24 Oct 2010 22:21:02 +0100

The Secretary of State might have saved himself some trouble by asking me about my coffee.

(Newbies refer to page 1 of this thread.)

Multifoil Insulation

fostertom — Sun, 24 Oct 2010 23:33:01 +0100

That coffee experiment was a poor man's hotbox, which we all know by now is a deeply flawed principle.

Multifoil Insulation

CWatters — Mon, 25 Oct 2010 12:30:46 +0100

Posted By: WatchIthttp://www.communities.gov.uk/publications/planningandbuilding/determination451238" rel="nofollow" >http://www.communities.gov.uk/publications/planningandbuilding/determination451238

well well...the debate takes another twist (against in-situ testing).

Not exactly a new twist. The BRE found that in-situ and hotbox tests gave similar results and the manufacturers haven't been able to convince the world there is a difference. So not really surprising they see no reason to change the way things are measured.

The research by Professor Eames is also interesting. He appears to have modeled a "super multifoil" made from aerogel to see how good a multifoil could possibly be...

31. More recent theoretical research by Professor Philip Eames of Loughborough University2, carried out for the Department after your full plans application was made, lends support to BREâ€™s conclusions. Professor Eames calculated the U-value of a typical roof construction insulated with multi-foil and compared it with the U-value of the same roof insulated with mineral wool â€“ in effect modelling the comparative tests carried out by TRADA and CIM. To do the calculations, Professor Eames assumed values for reflectivity (which is independent of thickness) and thermal resistance (which is dependent on thickness) corresponding to bright aluminium foil and foam layers respectively.

To determine the best possible system performance that could be achieved using the best materials currently available, he repeated the calculations for multi-foil comprising polished silver foil and aerogel layers. The predicted U-values were:
â€¢
200mm mineral wool (no reflective backing): 0.17 to 0.19 W/m2K
â€¢
100mm mineral wool (no reflective backing): 0.33 to 0.34 W/m2K
â€¢
Multi-foil â€“ typical (aluminium foil and foam): 0.35 to 0.50 W/m2K
â€¢
Multi-foil â€“ best possible (silver foil and aerogel): 0.23 to 0.27 W/m2K

Professor Eames therefore calculated that the predicted thermal performance of typical multi-foil material is worse than that of 100mm of mineral wool insulation; and even if made from silver foil and aerogel, it is worse than that of 200mm of mineral wool insulation.

Multifoil Insulation

WatchIt — Tue, 26 Oct 2010 14:08:42 +0100

well yes...a new twist.

BRE thing was at least 5 years ago now and it did nothing to stop Triso in Scotland or anywhere else. But Secretary of State, that packs much more of a punch in terms of BCO's and accepting these products (I don't in the slightest refer to any technical knowledge etc packing more of punch).

The report that made my mind up on multifoil claims was the NPL hotbox testing where they compared Triso to glasswool and Celotex, testing them all in the hotbox. We don't all know this test method is "deeply flawed" Tom...I for one believe this is by far the fairest test method we have.

Multifoil Insulation

fostertom — Tue, 26 Oct 2010 16:22:38 +0100

Posted By: WatchItWe don't all know this test method is "deeply flawed" Tom

In what way isn't it?

(perhaps you for one just don't know, full stop)

Multifoil Insulation

Mike George — Tue, 26 Oct 2010 17:22:56 +0100

One way in which the NPL report is flawed:

Source: excerpt from unpublished response to NPL Report MA8.

6.0 The effect of induced air flow on the hot box apparatus
6.1 Method:
1200mm x 25mm perforated strips were introduced at the top and bottom of the test samples. 1.2mm holes were used to produce an open are of 42%. This configuration attempts to replicate a ventilated cold roof scenario such as that which may be found in a typical loft conversion.
6.2 Limitations and results of the induced air flow:
6.2.1 It is not stated in MAT 8 why such small holes are used in the test sample. Real life ventilation in roofs utilises much larger apertures than this, in some cases slotted ventilation many times greater. An example is Anglian pvc-u Rooftrim system which utilises ventilation slots 35mm long by 3.5mm wide, a total surface area of approximately 122mm2 See BBA Certificate No 04/4180 available at http://www.bbacerts.co.uk/certs/41/4180i1_web.pdf
6.2.2 The amount of air flow is described only as â€˜smallâ€™. Unfortunately, this does not allow the reader to glean any meaningful understanding of the obtained results.
6.3 Results:
The results favour the Celotex and Knauf samples, with u-values increasing over corresponding [non vented] samples by 3.5% and 2.4% respectively. The Tri iso Super10 sample is reported to have an increase in u-value of 8.8% over the un-vented sample. It is unclear whether this â€˜smallâ€™ amount of air flow can possibly duplicate the dynamic real life environment found in a cold roof scenario.

Multifoil Insulation

WatchIt — Wed, 27 Oct 2010 09:16:03 +0100

But Mike, I see that as the point in using a steady state test method. Yes granted the induced air flow may or may not be similar to typical conditions in situ, but at least it is giving a level playing field on which ther performances are based. Otherwise you would have a different air flow for each product tested.

Tom, no "flaws" that you could nit pick at could be anywhere near as bad as comparative testing flaws and they way they could give a biased result.

Why do these manufacturers think it is acceptable to not test their products using a recognised test method, but its ok to compare it to something else (WHICH HAS BEEN TESTED PREVIOUSLY USING THESE RECOGNISED STANDARDS!!!!!)?

Multifoil Insulation

fostertom — Wed, 27 Oct 2010 10:28:19 +0100

Everyone incl the manufs agrees that MFs are completely useless in steady-state conditions, but luckily there's no such thing in the real world.

Artificially-induced steady-state such as in hotbox testing favours conventional mass-insulator materials - or rather, the manufs design them to do well in the hotbox and hang their real-world performance, which wd best be tested by in-situ comparative year-round method - but that's been given a bad name by guess-who, and even people on this forum have swallowed that propaganda.

Posted By: WatchItThe report that made my mind up on multifoil claims was the NPL hotbox testing where they compared Triso to glasswool and Celotex, testing them all in the hotbox. We don't all know this test method is "deeply flawed" Tom...I for one believe this is by far the fairest test method we have.

Simply allowing temp to vary in a slow and steady way within the hotbox bears no resemblance to real-world rapid micro-variation and reversal of temps. That is still equiv to steady-state, as far as MFs' operating principle is concerned. And that is what the NPL settle-this-once-and-for-all testers did, as their sop to the MF manufs' insistence that testing should be done under dynamically varying conditions. The NPL testers didn't bother to check out their silly methodology with the MF manufs - and why should they, as their paymasters' hidden brief was to run MFs out of town.

Posted By: CWattersthe manufacturers haven't been able to convince the world there is a difference

The Confed of Multifoil Manuf did indeed convince the European testing over-body that there is a difference and as a result a programme to build 13 v expensive dynamically-varying test rigs across Europe was put in hand. But for reasons I don't have info on, that decision was reversed. Conventional insulants would also have got tested, under real-world dynamically varying conditiions, and the results wd have been v interesting - and embarassing. The leading lights of the CMM effort seem to have accepted defeat (for now). For that reason I'm not now recommending or specifying MFs, because MF manufs' wholehearted tech backing isn't there at present

Multifoil Insulation

WatchIt — Wed, 27 Oct 2010 11:59:20 +0100

Everyone incl the manufs agrees that MFs are completely useless in steady-state conditions, but luckily there's no such thing in the real world.

Do you honestly beilieve that? I think we have a difficult situation where there are loads of industry professionals that don't want to accept they have been taken for a ride.

Have you seen the test reports on Aluthermo? Its a bubblewrap thats used alot here in Ireland, they completely contradict your "everyones" on steady-state conditions. When I first got told about Aluthermo, it was being sold based on comparative testing (you can find the report if you google it). However this comparative testing, unlike the others using this, failed to give them the magical 0.20 equivalent insulation value. So they now sell it based on some report they have where they show under steady state conditions, actually Aluthermo can get a u-value of 0.17. Absolute rubbish but thats what their report says.

One last thing Tom. I see the benefit of "in situ" testing...and would love some real work to be done on this using the recognised standard for it. But it is not to be confused with "comparative" testing where the thermal performance of an airtight material always seesm to be compared to that of a permeable one (and then taking the R-value from a test in which the material won't have been subject to air movement).

Multifoil Insulation

James Norton — Wed, 27 Oct 2010 12:40:17 +0100

Well done chaps, good to see another surge of input, 261 more to go...

Come one...!

J

Multifoil Insulation

biffvernon — Wed, 27 Oct 2010 12:55:42 +0100

And still the physics is ignored.

Multifoil Insulation

fostertom — Wed, 27 Oct 2010 13:02:27 +0100

Posted By: WatchItloads of industry professionals that don't want to accept they have been taken for a ride

Certainly the old scientists who have safeguarded BRE's 50yr development and application of hotbox methodology - and the entire conventional insulation industry.

Posted By: WatchItan airtight material

one of the standard red herrings - most MFs are peppered with stitch holes so none of thelr performance can be attributed to airtightness.

Posted By: biffvernonAnd still the physics is ignored

and you in particular Biff have consistently stonewalled alternative interpretations of physics that have been offered. 'Stonewalled' means not disputed - just ignored.

Multifoil Insulation

Paul in Montreal — Wed, 27 Oct 2010 13:04:00 +0100

Tom, I already posted a link to a paper on the physics of foil faced insulation that takes into account all the effects you claim are ignored through proper use of polynomial equations and correlations with actual measurements. The physics is well understood and your claim that there's a difference between steady-state and dynamic performance is simply naive as you obviously don't understand the physics of heatflow described in the paper - this is fine as it's a complex subject, but it's not mysterious. Once again, go to page 26 of this: http://books.google.com/books?id=miXWZMuRE_8C&lpg=PA460&ots=uy_uvEhgGo&dq=aerogel%20infrared%20%2BMie%20%2Bscattering&pg=PA460#v=onepage&q=aerogel%20infrared%20+Mie%20+scattering&f=false

(The link above returns the page on how aerogels with IR absorbers work, but if you go to the contents link and navigate to page 24 in the index you'll get the paper entitled: "Prediction of the thermal performance of single and multi-airspace reflective insulation materials").

I invited you to look at this link already in this thread here: http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=125&Focus=83415#Comment_83415 on June 3rd.

Paul in Montreal.

Multifoil Insulation

fostertom — Wed, 27 Oct 2010 13:08:16 +0100

True Paul - I've never followed those up fully - believe I see the flaws, with my limited physics, intended to run it past my boffin colleague, but keeping him fully occupied with other things at the mo.

Multifoil Insulation

WatchIt — Wed, 27 Oct 2010 13:46:59 +0100

A red herring!! Try dynamic real life conditions, or rapid micor-variation, or the best of all MFI is special and doesn't work under steady-state. There's a red herring. Holes can be covered, I accept airtightness suggests nothing will get though when in practice thats all but impossible, but the effect of a few stitched holes can't be comparted to something like fibre glass.

Stonewalled is a good word for ignored. And ignoring some of these awful interpretations is the nicest possible way of dealing with them. PHYSICS doesn't even need to be dragged into this, its common sense.

Multifoil Insulation

WatchIt — Wed, 27 Oct 2010 13:48:20 +0100

Paul, do you know where I can get that in paper form? I would like to read it but would prefer some paper to square eyes!

Multifoil Insulation

Paul in Montreal — Wed, 27 Oct 2010 14:00:29 +0100

http://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1116.htm

"Brings together the latest research data on thermal insulation materials. 38 papers cover:

â€¢ Reflective/Radiant Barriers/Radiation Control Coating

â€¢ Economics and Energy impact

â€¢ Long-Term Thermal Performance of Foams

â€¢ Assessments and Properties of Foams

â€¢ Convection in Fibrous Insulation

â€¢ Tests and Models

â€¢ Performance Factors

â€¢ Innovative Insulations

â€¢ Test Methods and Comparisons

Table of Contents

Overview
Graves R., Wysocki D.

Preliminary Assessment of Radiation Control Coatings for Buildings
Anderson R., Yarbrough D., Graves R., Wendt R.

Prediction of the Thermal Performance of Single and Multi-Airspace Reflective Insulation Materials
Desjarlais A., Yarbrough D.

A Stratified Air Model for Simulation of Attic Thermal Performance
Parker D., Fairey P., Gu L.

The Use of Economic Analysis in Developing an Energy Standard: Lessons Learned
McBride M.

Energy Code Measures to Assure the Effectiveness of Thermal Insulation Installed in Buildings
Nelson B.

A Survey of Loose-Fill Insulations Installed in Residential Attics
Penney R., Yarbrough D.

Zip 2.0: The Enhanced Zip-Code Insulation Program
Petersen S.

Evaluation of Long-Term Thermal Performance of Cellular Plastics Revisited
Bomberg M., Kumaran M.

Thermal Measurement of In-Situ and Thin-Specimen Aging of Experimental Polyisocyanurate Roof Insulation Foamed with Alternative Blowing Agents
Christian J., Courville G., Graves R., Linkous R., McElroy D., Weaver F., Yarbrough D.

Fundamental Aspects of Thermal Conductivity Aging and Dimensional Stability of Rigid Polyurethane Foams
Smits G., Thoen J.

Some Factors Affecting the Long-Term Thermal Insulating Performance of Extruded Polystyrene Foams
Booth J.

Thermal Performance of HCFC-22 Blown Extruded Polystyrene Insulation
Yarbrough D., Graves R., Christian J.

CFC Blowing Agents Substitutes â€” A Status Report
Zwolinski L., Knopeck G., Shankland I.

A Review of Techniques for Improved Foam Conductivity: Reducing Radiation Heat Transfer, Limiting Aging and Inclusion of Vacuum Elements
Glicksman L., Burke M., Marge A., Mozgowiec M.

The Effect of Natural Convective Air Flows in Residential Attics on Ceiling Insulating Materials
Rose W., McCaa D.

Thermal Performance of One Loose-Fill Fiberglass Attic Insulation
Wilkes K., Wendt R., Delmas A., Childs P.

Forced Convection Effects in Fibrous Thermal Insulation
Silberstein A., Arquis E., McCaa D.

Experimental Test Results of Interior Vs. Exterior Insulation in Extremely Hot Climates
Al-Mofeez I., Woods P.

Hot Box Instrumentation, Calibration and Error Estimation â€” A Survey
Miller R., Goss W.

Comparison of Heat Transfer Modeling with Experimental Results for Residential Attic Insulations
Gorthala R., Roux J., Levins W., Wilkes K.

Combined Conduction, Radiation Heat Transfer and Mass Transfer in Fibrous Attic Insulations
Gorthala R., Roux J., Fairey P.

Moisture Diffusion in Thermal Insulating Materials
Freitas V., Crausse P., Abrantes V.

The Effect of Exterior Insulating Sheathing on Wall Moisture
Tsongas G.

Thermal Conductivity of Several Concretes as a Function of Moisture
Ashworth T., Ashworth E.

Thermal Insulation Under Fire
Schultz N.

Gas-Filled Panel High-Performance Thermal Insulation
Griffith B., Arasteh D., Selkowitz S.

Aerogel â€” A High Performance Insulating Material at 0.1 Bar
Hunt A., Jantzen C., Cao W.

Reduction of High Temperature Thermal Conductivity of Thin-Wall Ceramic Spheres
Chapman A., Cochran J., Ford T., Furlong S., McElroy D.

Automated Low-Temperature Guarded Hot Plate for Measuring Apparent Conductivity
Smith D., Dube' W., Filla B.

Intra-Laboratory Comparison of a Line-Heat-Source Guarded Hot Plate and Heat-Flow-Meter Apparatus
Zarr R.

A Round-Robin Comparison of Australasian Thermal Laboratories
Trethowen H., Desjarlais A.

Interlaboratory Comparison of the Apparent Thermal Conductivity of a Fibrous Batt and Four Loose-Fill Insulations
McCaa D., Smith D., Desjarlais A., Graves R., Mumaw J., Noonan P., Scott J., Sikund R., Troyer R., Zarr R.

ASTM/DOE Hot Box Round Robin
Bales E.

Thermal Properties of Selected Materials from Steady-State and Transient Tests
Graves R., Yarbrough D., McElroy D., Fine H.

Underground Cellular Glass Pipe Insulation Failures in Quebec and Louisiana
Lotz W.

Effects of Aeration on Corrosiveness of Wet Residential Building Thermal Insulation on Low Carbon Steel
Stansbury E.

Tensile Testing of EIFS Laminas
Flanders S., Lampo R., Davies A.

Field Performance, Hydrolysis and Durability of Urea Formaldehyde Foam Insulation in Australian Dwellings
Brown S.

Multifoil Insulation

fostertom — Wed, 27 Oct 2010 15:16:06 +0100

Posted By: WatchItits common sense

The last resort of the 'ay oop' conservative.

Posted By: WatchItthe effect of a few stitched holes

Get a sample of MF and tot up the area per m2 of the stitch holes - as far as I remember it's equiv to a 80mm diam hole. How much larger than that wd become significant? Tho there are imperforate MFs now, the ones that took part in those old comparative tests were as leaky as a sieve. So let's drop that 'due to airtightness' myth.

Multifoil Insulation

djh — Wed, 27 Oct 2010 15:40:56 +0100

Posted By: Paul in Montrealhttp://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1116.htm" >http://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1116.htm

"Brings together the latest research data on thermal insulation materials.

Before everybody gets too excited, note that it was the latest research data in 1991 when it was published!

Insulation Materials: Testing and Applications, 2nd Volume

Graves RS, Wysocki DC
Pages: 636
Published: 1991

Multifoil Insulation

WatchIt — Wed, 27 Oct 2010 15:57:19 +0100

Tom, did you read a couple of words and ignore the rest? you would need more than, equiv 80mm diam hole, before it would be a comparative permeability to standard fibre glass. hence the rest of the sentence overlooked.

Multifoil Insulation

Paul in Montreal — Wed, 27 Oct 2010 16:03:16 +0100

Posted By: djhBefore everybody gets too excited, note that it was the latest research data in 1991 when it was published!

It may be old, but the problems that Tom claims are being ignored are right there in the research back then - even a paper on transient response of insulation and ways to solve the energy and radiation equations in changing conditions simultaneously. Everything he claims is not taken into account is right there in the papers. This is not rocket science! Even papers on the aging of foam-based insulation (recent discussions here about that too). There's a particularly interesting paper about insulation in attics in both unfaced and foil-faced configurations that correlate actual test house measurements with the physics used to describe them - and yet we still see people claim here that in "real world" situations everything is somehow different or doesn't apply.

Paul in Montreal.