Talk:R-value (insulation)

message: "In the absence of radiation or convection, the surface temperature of the insulator should equal the air temperature on each side."
This is impossible.  If you visualize thermal gradient as a voltage drop, there is obviously a thermal difference when using a conduction model of heat transfer.  —Preceding unsigned comment added by 146.145.138.42 (talk) 20:21, 25 August 2010 (UTC)
replies: text: Well there is never an absence of radiation or convection, but in the usual case it is a thin layer of non-moving air near the surface that limits heat transfer.  In the absence of that layer, the boundary condition is as indicated. Gah4 (talk) 10:56, 22 January 2019 (UTC)
thread_title: Another impossibility

message: How does the rate work without factoring time into the equation?  In the formula example used the answer is 5 watts per sq m.  That doesn't mean anything without time.George Swantner 18:55, 14 September 2007 (UTC)
replies: text: One watt is equivalent to one joule per second.  The measurement and subsequent calculation (see ASTM C177 for more info) is based on heat flux (q - heat loss/gain per unit area per unit time), is taken while the sample is at steady state, meaning that there is no change with time, or \frac{\partial q}{\partial t}=0.  I hope this helps.  Bill Fabrizio --65.206.71.3 (talk) 17:48, 21 January 2009 (UTC)

text: To avoid confusion, I think Wikipedia should default to SI units. 217.121.144.89 09:23, 28 May 2005 (UTC)
replies: text: Good changes. I didn't want to appear like some avenging crusader, which probably impaired my clarity.Limegreen 00:17, 29 May 2005 (UTC)
thread_title: How does the rate work without factoring time into the equation?

message: I think it would be useful to make it clear that the "some other countries" that use the BTU definition of R-factor include the United States.  Also, I think it would be useful to give a straightforward defintion of the U.S. version of R-factor in W/m2KPciszek 19:15, 15 March 2007 (UTC)
thread_title:  "Some other countries" = "U.S."? 

message: I think of great value would be a section on how this law about the R-Value being the standard for heat transfer for insulation in the US came about. About how "Company Pink" made a deal with congress to get this law passed (which had an insulation with very good R value but quite low conductive and radiative values) which made R-Value the standard. Also how the R-Value rule is keeping many good competitors from being profitable because they have lower R values but much better values for the other two types of heat transfer. I can't give citations on this, but my physics professor ranted for ten or so minutes on it. I'm sure some of you have heard of this. Ergzay 03:12, 21 September 2007 (UTC)
thread_title:  Company Pink 

message: It doesn't seem that the single reference link (PDF file) contains any verifiable information and is not directly related to any information on the page (in fact, it contradicts much of it). Moreover, the target of the link is on a commercial site and clearly promotes a product.
----  —Preceding unsigned comment added by 68.147.142.222 (talk) 19:29, 12 October 2007 (UTC)
thread_title:  Reference spam 

message: I just removed this discussion from the article, thinking that it belonged on the talk page.  So here it is:
"Correction! The transfer of heat by conduction is specific ONLY to a material's specific resistance to that transfer. The only fixed factor is the material's density which in turn determines its resistance or "R" value. ONLY If the material is porous, could the the R value include convection or radiant transfer potential. The National Fire Service describes CONDUCTION as "heat transfered between two solid surfaces in DIRECT contact with each other that allows heat to be transfered between physical objects." By definition, this would exclude radiant and convective transfers as these means are based on radiance or particles in cirrculation. Simply because the " thermal Insulation Community" dislike competitive products that make insulation more effective, is no reason to rewrite basic scientific principles. "
I think the above is unclear and confused and inappropriate style for wikipedia, but thought it might be more productive to put it here than just delete it.  It's true that most solid materials don't have convective or radiative heat transfer inside them, but most insulation materials are not homogeneous solids.  I'm also not sure the relevance of the NFS definition of conduction.Ccrrccrr 04:26, 16 October 2007 (UTC)
thread_title:  Discussion of what it includes 

message: Another section removed:
:Similarly, bulk insulators can be easily overwhelmed by solar radiation during summer (where black globe temperature far exceed ambient air temperatureshttp://www.bom.gov.au/info/thermal_stress/ but are much more effective in reducing winter convective losses.  Often a judicious combination of both materials is required to achieve an optimum solution for a mixed climate.
::WBGT is designed for assessing heat stress for people who are outdoors.  Figuring out how to apply it to buildings is not straightforward and would be original research.  That sounds useful, but it doesn't belong in Wikipedia.Ccrrccrr (talk) 14:15, 14 December 2007 (UTC)
replies: text: Wet bulb globe temp is not the same as black globe temp.  My point being that when insulation is modelled, is it being subjected to the same radiation flux as would experienced during summer.  Furthermore, is it measuring the temperature of the ambient air on each side of the insulator or the temperature that is also due to the effects of radiation (black globe temp or mean radiant temperature).  This would markedly change the results of any formula on 'thermal conductivity' that you use.Dymonite (talk) 10:00, 23 December 2007 (UTC)
thread_title:  Overwhelming bulk insulators 

message: I removed this sentence:
: The measured heat transfer will vary depending on the type and intensity of heat source used in the model.
If you have a conventional bulk insulator, the heat transfer through it comprises radiation, convection, and conduction.  The mix of those three does not depend on the mode by which the heat arrives at the surface of the test box.  Once the heat arrives at a wall, it is just heat, regardless of how it arrived there, and it's free to proceed through the wall by whatever means is permitted by the insulation there.  It's not like heat that arrives at the wall as radiation can only go through the wall as radiation.Ccrrccrr (talk) 13:15, 15 December 2007 (UTC)
thread_title:  Type of heat source used 

message: Reader's comment: I Subscribe to the U.S. FTC prohibition to the use of R-value per inch.  So this section "Values per inch" is not appropriate (in the USA).  Tables or graphs should be developed based on specific available products.
(not my comment--I'm just the editor the moved it here from the article.  Note that the article has a discussion of this issue in the section above the list of R-values.Ccrrccrr (talk) 03:22, 8 January 2008 (UTC)
thread_title:  "Reader's Comment" 

message: This recent edit changed some of the references and left both conflicting (autogenerated1) and undefined (autogenerated3) references.  I'm just passing through and don't have the expertise to straighten these out.  -- Tcncv (talk) 04:01, 31 October 2008 (UTC)
replies: text: Thanks--I think I fixed it but I encourage people to check.  —Preceding unsigned comment added by Ccrrccrr (talk • contribs) 23:29, 31 October 2008 (UTC)
thread_title:  Refernce errors 

message: Modified by David Lambert, lambertdw@corning.com  —Preceding unsigned comment added by 69.205.128.181 (talk) 21:03, 22 November 2008 (UTC)
replies: text: The thermal resistance of the glass itself is negligible, as you probably know.  The thermal resistance is all in the heat transfer from the room to one surface, and from the other surface to the outside....or vice versa for heat flow in the other direction.  That is how it is normally discussed.  It's analogous to the R-value of a whole wall assembly that includes those surface effects on inside and out, plus the wallboard, plus the insulation, etc., rather than being analogous to the value for a single material.Ccrrccrr (talk) 22:09, 22 November 2008 (UTC)

text: Consider three stage system comprised of convection, conduction, convection.  The heat transfer rate across entire thing is keff*area*(Toutside-Tinside).  Because of steady state the convective transfers balance the conductive transfer balance the net rate.
These three equations are just right to determine the three unknowns: keff, and the surface temperatures of the glass.
Substituting gold foil properties has negligible consequence, as you say.  Thank you for clarification.  Agreement using this calculation is quite good.
199.197.135.180 (talk) 22:16, 2 December 2008 (UTC)

text: Which language/syntax are you using? — Sebastian 08:08, 28 December 2008 (UTC)
replies: text:  Mathematica, maybe? --DavidCary (talk) 13:05, 9 June 2014 (UTC)
thread_title:  Reported R-value for single pane window glass. 

message: The concept of U-value is frequently first taught to engineers (at least mechanical engineers) in the context of heat exchangers, where it is introduced as the 'overall heat transfer coefficient' between one fluid, via a steel wall, to another fluid, including convection, conduction, convection. This definition is much more robust and universal, and needs to replace the definition given on this page. It should furthermore be pulled out into a page of its own, because most students will learn about U-values before they first hear about R-values and R_th. Jdpipe (talk) 01:52, 27 February 2009 (UTC)
thread_title:  Definition of U-value 

message: I mistakenly reverted a formula added to the lead:
:It is the ratio of the temperature difference across an insulator and the heat flux through it, i.e., R={\Delta T}/{\phi_q}.
I was thinking of the math/electromagnetics definition of flux, not realizing that a different definition was used in transport phenomena.  Sorry about that!
Ccrrccrr (talk) 12:56, 13 July 2009 (UTC)
replies: text: Thx. The general term might be energy flux and apparently that term also has some ambiguity in its use. There is a lot of variation in the symbols and terms used for "heat flux". A quick search of the internet showed that q and Q are often used. My edition of the Handbook of Chemistry and Physics lists a number terms used to express transport properties and they use Jq for heat flux (units W/m2). I used φq to be consistent with the usage in heat flux and minimize the amount of confusion within Wikipedia. --Jbergquist (talk) 00:44, 14 July 2009 (UTC)

text: Minimizing the amount of confusion in WP sounds like a large project!  More seriously, I do like the idea of Jq, because it would be more readily understandable to people who have a background in electromagnetics, since J is used for the analogous quantity current density.  Q is problematic because it's used both for quantity of heat and for heat flow.  Q dot would seem to me to indicate a time derivative of one of those, but is often used to indicate heat flow rather than heat--that seems problematic to me, though I see someone just put it in here that way.  (Derivative and flow are different concepts--it's quite possible to have steady non-zero flow with the derivatives all zero.)Ccrrccrr (talk) 01:20, 14 July 2009 (UTC)
replies: text: The R-value relating the temperature difference and the heat flux is a formula for a transport phenomena. Consider the analogy with Darcy's law which relates the pressure difference across and the flow of water through some material and the similarity of the constant of proportionality with resistance. The formula we are working with is analogous with Ohm's law in which R is the constant of proportionality between the potential difference across and current through a resistor so making the changes you will overcomplicates matters. These analogies give us the Q and the R. I don't like the use of J because that is used for the current density vector and heat flux is a scalar. --Jbergquist (talk) 02:27, 14 July 2009 (UTC)
replies: text: In general heat flux is a vector.  See heat flux.  The thermal resistance equation, (heat flow, e.g. in watts) = ΔT/Rth, where Rth is thermal resistance in K/W, is analogous to ohm's law, not the equation with R-value in the position of R.  Ccrrccrr (talk) 02:47, 14 July 2009 (UTC)

text: The analogy isn't exact. What's involved in the analogy is a "potential difference", a scalar flow and a constant linking them. Ohm's law would involve "fluxes" (and an extra m2 unit) if we considered the flux of current through a square slab acting as the resistor. You don't need to worry about the thickness of the slab when "potential differences" are used.  --Jbergquist (talk) 03:35, 14 July 2009 (UTC)

text: Here's a problem someone might like to add: What is the thermal resistance of 8 16"x96" sheets of R-19 insulator? At what rate will heat will flow through them if the temperature difference across them is 20 °F? --Jbergquist (talk) 04:12, 14 July 2009 (UTC)
thread_title:  Formula in lead 

message: Using the watt to describe both the rate at which work is done and the rate of heat flow can be confusing in this situation. It may help if some derived unit could be used to measure the heat flux instead of W/m2. The best name for this unit of heat flux [φq] may be the "fourier". It might be abbreviated as Fo avoiding confusion with the franklin, the Froude number or Francium and in conformity with the abbreviation for the Fourier number.  Then the units for the R-value would then be [T]/[φq] which would be °C/Fo and that of the U-value would be Fo/°C. --Jbergquist (talk) 22:07, 14 July 2009 (UTC)
replies: text: Whether to use different unit names for energy flow in different situations is an interesting question, and one about which I'd love to tell you my strong opinions.  However, it's not something that should be discussed on this page, because even if we editors developed a consensus on a great plan along those lines, we'd still be prohibited from mentioning it in this or any Wikipedia article, because it would be our original research.Ccrrccrr (talk) 00:58, 15 July 2009 (UTC)
replies: text: I agree that the idea is somewhat premature and not suitable for inclusion in a Wikipedia article. But it occurred to me that we might encounter some absurd expression like W/W while discussing the rate of heat flow at a given power expenditure needed to maintain an equilibrium in temperatures where "Fo-m2/W" might be clearer. With respect to global warming passive systems may be preferrable and active systems counter-productive. High R-value is definitely low carbon but a building needs to allow for an exchange of gases too. --Jbergquist (talk) 05:31, 15 July 2009 (UTC)
replies: text: "some absurd expression like W/W".  Like Coefficient of Performance?Ccrrccrr (talk) 13:13, 15 July 2009 (UTC)
thread_title:  Would it help to remove some of the ambiguity in W/m<sup>2</sup>? 

message: The table detailingspecific R Values should be corrected to show SI values with regional and non SI units in brackets and not the other way around. — Preceding unsigned comment added by 86.1.65.206 (talk) 18:02, 20 September 2009 (UTC)
replies: text: Agreed that table should be changed to SI units with non SI units in brackets.  —Preceding unsigned comment added by 122.104.137.248 (talk) 11:39, 3 October 2009 (UTC)

text: The non-SI values were put inside brackets some time ago. The current version of the table has them in a separate column altogether. kk, the reason for the inclusion of the "inch" with the SI units is given in "Incoherence in SI units" on this talk page. The R-value has its origin in the US. I don't think there's a conspiracy. Pololei (talk) 19:24, 17 June 2016 (UTC)
thread_title:  Use of non SI unit in preference to SI 

message: According to Halliday & Resnick, Fundamentals of Physics, Third Edition, 1988 on p. 473, R value of window glass in US units is 0.14. The table in the article shows 0.24. However if you start with the value on Wikipedia for the thermal conductivity of glass provided in the article on that topic, which is 1.1 in SI units, you can prove the 0.14 value is correct. R = thickness / thermal conductivity = 0.0254 m / 1.1 = 0.0231, which in US units is 0.1311.
Couldn't figure out how to edit the table myself, but the error just cost me several hours, so I thought I'd report it.
71.235.72.45 (talk) 03:32, 21 March 2010 (UTC)
replies: text: Thank you for catching this! The reason why it was hard to edit was not (primarily) because it's in a table, but because the table has been transcluded, which is quite unusual. The actual page that needed to be changed was Insulation (list of insulation material). — Sebastian 22:45, 26 March 2010 (UTC)
thread_title:  R-value for glass in table is incorrect 

message: 1 h·ft²·°F/Btu = 3600s·(0.3048m)²·1.8K/1055.05585J = 0.570597 K·m²/W. Not 0.176110 K·m²/W as in article.
No, the original (0.176110) is correct, see the ASHRAE Fundamentals reference. You multiplied by 1.8 °F/K, you should be dividing by 1.8 °F/K. Elfstrom (talk) 05:58, 17 October 2010 (UTC)
thread_title:  Units conversion is not correct? 

message: Can we add to the table of typical values some of the more common construction materials eg
drywall/plasterboard/gypsum board ? Rod57 (talk) 23:05, 30 November 2010 (UTC)
replies: text: RSI 12.5mm drywall seems to be about 0.08. Rod57 (talk) 23:36, 30 November 2010 (UTC)
thread_title:  Typical value for drywall/plasterboard/gypsum board 

message: The article says that R-value is expressed as the thickness of the material divided by the thermal conductivity.  The SI unit m2K/W is in accord with this, provided the thickness is included along with the thermal conductivity.  Without a specified thickness the definition is meaningless.
The knee-jerk physicist response would be that what is really meant here is that [R-value] is simply the reciprocal of thermal conductivity, whose units would be mK/W.  Otherwise, says the physicist, how could a quantity given in units of m2K/W be used?  What if I have one sheet of glass of thickness 3 mm and another 6 mm?  How do I use R-value consistently with its units to get different heat fluxes for each?
The only way I can make sense of this is if R-value is not a property of materials in the sense of physics but of construction materials of known thickness. You would then give separate R-values for 3 mm and 6 mm glass.  Typically when selling a product by the square foot such as drywall or batting or window panes you would also have other attributes to hand, allowing other factors to be taken into account.
It seems to me that the article gets this wrong in the fourth sentence, This is used for a unit value of any particular material.  A more accurate statement might be This is used for unit area of a construction material with known relevant attributes such as thickness, emissivity, etc.
As others have pointed out the temperature unit is wrong for radiation, in particular for emissivity, about which the article could presumably say something; it should be K4, not K.  It could not of course propose unsourced solutions, but with the thought in mind that the building industry evidently refers to these talk pages, one solution might be to adopt a standard room temperature, say 20 °C for SI units and 70 °F for US, and give two R-values in units of m2/W or ft2h/Btu, one for each of two representative outside temperatures, from which the relative contributions of the conductive and radiative components might be deducible from the distance of the line connecting the two temperatures from the origin (outside temperature equal to inside).  This would have the additional benefit of simplifying the units and using the value by removing temperature from both the unit and the computation.  Convection is a bit of a spoiler there. --Vaughan Pratt (talk) 18:59, 15 December 2010 (UTC)
replies: text: Seems that no-one answered this for some years, but yes it is for specific thicknesses.  In many materials, it is a combination of conduction and (hopefully slow) convection.  Consider popular glass fiber insulation as an example. You buy a batt or roll of such, with a design thickness.  It is, then, not necessarily proportional to thickness.  If there is an air flow barrier, then you can add the values of stacked insulation.  If there isn't, it might be a little different.  Also, compressing it can change the R value. Gah4 (talk) 04:36, 11 February 2019 (UTC)
thread_title:  What thickness? 

message: There is a "citation needed" annotation, which I think is intended to express a need for documentation or adjustment to the phrase "this linear relationship may be only approximate for some materials".
While this might not be the best phrasing, I think the original purpose of the phrase was to indicate that the R-value of a structure cannot necessarily be determined by multiplying the "R-value per inch" of its component material by its thickness.  A clear example is an airspace; the R-value of an 1/2 inch airspace is about 1 (in US units), while the R-value of a 4 inch space is virtually the same.
The FTC determined that the potential for misleading claims was so high they essential banned the use of "R-value per inch" as an advertising claim.
I'm not so clear on the best way to present this in the context of the article.  — Preceding unsigned comment added by Wcoole (talk • contribs) 22:56, 10 February 2011 (UTC)
replies: text: Also, if you compress some materials, such as glass fiber, the value will change in a not so obvious way. Gah4 (talk) 04:39, 11 February 2019 (UTC)
thread_title:  Linear relationship 

message: The cited values for straw bale R the value is with respect to a study that even the link referenced said it is questionable (circulation behind drywall facing changing value). As such, and since this page is talking about basic R-values and not combinational values, shouldn't the more accepted values be used? 
eg R-2.68 per inch to R-2.38 per inch, rather than R-0.94 per inch
SanityChek (talk) 03:08, 15 November 2011 (UTC)
thread_title:  Straw Bale values 

message: I remove the following phrase: "The general rule for the general effectiveness of insulation is that one inch of insulation roughly equals 30 inches of concrete.", along with reference to http://rvalue.net/ as it is impossible to create a direct comparison between "insulation" and "concrete." The link simply states this as fact. This is similar to saying "buses" carry 60 times more passengers than "cars" - simply too vague to be useful. Andy (talk) 10:13, 6 February 2012 (UTC)
thread_title:  Removed comparison to concrete 

message: Could some one add "This article is about X, look R-factor (crystallography) for Y" template to article? — linnea (talk) 17:28, 10 May 2012 (UTC)
replies: text: "This article is about R-value in thermal resistance. Look R-factor (crystallography) for R-value used in chrystallography." — linnea (talk) 08:15, 11 May 2012 (UTC)
thread_title:  R-factor (crystallography) 

message: :: The article is R-value and the discussion is U value.  Let's have an R-value discussion here and a U value discussion elsewhere.
Dhunt16 (talk) 17:05, 29 November 2014 (UTC)
replies: text: Since U is just 1/R, there doesn't seem to be a lot of reason for a separate article, but one could be added. R is convenient as it is close to additive. For now, U-value redirects here, so it should be described here. Gah4 (talk) 04:46, 11 February 2019 (UTC)
thread_title:  U-value discussion 

message: "There has been a test method conceived to test the flammability of thermal/acoustic insulation. This type of insulation usually contains a thin film of moisture barrier over a batting material, with the possibility of foam being a second barrier. The test also takes into account small detail parts of the insulation which might contribute to whether or not the insulation is flammable.  Such details include thread, tape, and fasteners. The test consists of putting the insulation next to an ignition source, then observing whether or not it catches fire. Then, if the specimen has caught fire, the ignition source is removed and the insulation is observed to see if it continues to burn.United States. Federal Aviation Administration. Thermal/Acoustic Insulation Flame Propagation Test Method Details. Washington, D.C. : U.S. Dept. of Transportation, Federal Aviation Administration, 2005."
This has nothing to do with R-value; it also made no sense where it was in the article. Huw Powell (talk) 06:27, 9 November 2015 (UTC)
thread_title:  Removed from "aging" subsection 

message: The article states that the higher the R Value, the better the insulation effect. So given that U Value is the inverse of R Value, then the lower the U Value, the better the insulation effect. It would be nice for the article to say so.
173.79.59.113 (talk) 16:24, 21 January 2016 (UTC)
replies: text: The section on U-value says, "A low U value usually indicates high levels of insulation". It is implied in the lead section, too. Pololei (talk) 18:39, 21 January 2016 (UTC)
thread_title:  Practical meaning of U-value 

message: I was looking for R values for hempcrete. Closest thing I found was a .AU site saying "R4 for 300mm". This may be US or SI units - probably the latter.
I also didn't see any way to add the entry to the table.  — Preceding unsigned comment added by 70.66.191.220 (talk) 01:50, 23 November 2016 (UTC)
thread_title:  R values of Hempcrete 

message: The use of Kelvin when a temperature difference seems to make the article less accessible.  Most normal people think of temperature in Celsius and examples give a temperature in Celsius.  As the 'RSI' value is a delta of temperature the 'C°' notation can be used.  Especially as 'K' can be confused with a 'Kilo' notation.  Many people will not be familiar with Kelvin and having random 'K' as an abbreviation makes the article less accessible even if it is the unit used by technical people. 108.161.125.86 (talk) 13:43, 17 April 2017 (UTC)
replies: text: Although it's less widely recognised than the degree Celsius, the kelvin is the SI unit for temperature. RSI is numerically equivalent to thermal insulance when expressed in SI units. Pololei (talk) 04:25, 31 March 2019 (UTC)
thread_title:  Use of Kelvin 

message: Hello fellow Wikipedians,
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thread_title:  External links modified 

message: I was looking up the pipe insulation, which has cylindrical symmetry, and which is given an R value.  I understand how resistivity works in radial (cylindrical) coordinates, but it isn't so obvious here.  This article assumes flat materials, with the same area on each side, which is not true for pipe insulation.  Gah4 (talk) 11:11, 22 January 2019 (UTC)
replies: text: There's an article on pipe insulation that has a section on what you are interested in: Pipe_insulation#Heat_flow_calculations_and_R-value Someone should link it in the article. Ccrrccrr (talk) 02:59, 11 February 2019 (UTC)
replies: text: Interesting, and conveniently doesn't answer the question. After the post, I was thinking that it should be per linear (distance), since (as with flat insulation) it is rated based on the specific dimensions.  (That is, different diameters are quoted separately.)  But I thought it could also be based on either the inside our outside area, which the one you point to conveniently ignores.  Thanks, though. Gah4 (talk) 04:15, 11 February 2019 (UTC)
thread_title:  pipe insulation 

message: Do the references, which I don't have available, really give the conversion factors to/from SI units, to 10 significant digits?  Considering that insulation materials are probably accurate to one digit, that seems excessive. Gah4 (talk) 03:32, 9 February 2019 (UTC)
replies: text: I agree, that's excessive, but technically it's probably valid, given that that's derived from other unit conversions like inches to meters and joules to BTU, which are defined very precisely.Ccrrccrr (talk) 03:01, 11 February 2019 (UTC)
replies: text: If the reference has the digits, then it is hard to complain, even if excessive.  Recomputing the constant from known conversions is, as you note, technically valid, but I think not necessary. I suspect that there are no cases when one needs that conversion, even more generally than R values, to that many digits.  I was in college not long after calculators pretty well replaced slide rules, and giving values to 10 digits was common, and TAs were good at marking them off.  I remember once when the answer involved only the constants c, e, and 2, where the 2 should be exact.  I was still marked off for excessive digits.  I don't have the reference available to look them up, though. Gah4 (talk) 04:06, 11 February 2019 (UTC)
thread_title:  [[sig figs]] 

message: I understand what the writer was intending to convey with this.  However, two-dimensional is not accurate in this case, as some degree of thickness is always required.  — Preceding unsigned comment added by 206.174.219.186 (talk) 19:08, 21 January 2020 (UTC)
thread_title:  "two-dimensional barrier" 

message: An editor has asked for a discussion to address the redirect Orders of magnitude (thermal insulance). Please participate in the redirect discussion if you wish to do so.  Utopes (talk / cont) 22:24, 11 April 2020 (UTC)
thread_title:  "Orders of magnitude (thermal insulance)" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] 

message: An editor has asked for a discussion to address the redirect Square metre-Kelvin per Watt. Please participate in the redirect discussion if you wish to do so.  Utopes (talk / cont) 22:24, 11 April 2020 (UTC)
thread_title:  "Square metre-Kelvin per Watt" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] 

message: I found this article on the effects of aging on the R-value of some insulative materials. I haven't been able to check out the paper itself, but I would think that the National Center for Preservation Technology and Training is a trust-worthy source on this topic. If anyone can add some of this info to the topic on the effect of aging, I think that would be great. --IanVG (talk) 19:31, 27 September 2021 (UTC)
replies: text: Actually, I went ahead and made the changes I was considering. Please let me know if they seem appropriate. I think the section on aging could use an hour or two of dedicated time looking up trustworthy sources on this topic and adding summarized version (or simply their existence as references) to add more credence to the article's coverage. --IanVG (talk) 19:48, 27 September 2021 (UTC)
thread_title:  Source for Four Materials in Aging of Insulative Materials 

message: "U-Values of materials are found by observation under standardised conditions. The usual standard is at a temperature difference of 24 °C, at 50% humidity with no wind (a smaller U-factor is better at reducing heat transfer). It is expressed in watts per square metre kelvin (W/m2⋅K)." 
This seems out of place and the link does direct to a valid source anymore. Also, I may be wrong but I thought I remember reading that the R-value (and thus the U-Value) for commercially sold products is calculated by using a mean temperature of 75F with a base of 50F and a max of 100F. This may be a ASTM or ASHRAE test (ie. american-centric), so maybe acknowledging that other standards are present would be a good idea. I also don't think the lengthy discussion about the U-value is appropriate here. --IanVG (talk) 20:10, 27 September 2021 (UTC)
thread_title:  Partial Deletion of Introduction 

message: The chart, Typical R-values, is full of calculation errors. I'm not sure how these were sourced, but when I started plugging values into a spreadsheet to get a ratio, I ran into some oddities. For instance, the ratio between "RSI-value (m2·K/W)" and "RSI-value (m2·K/W) (per metre)", appears to be about 0.025, but for Insulated Glass, the ratio reported is 0.00875. I was thinking about trying to fill in a couple holes, but if the numbers are as trustworthy as they appear, I'm not sure I should bother.
I'd just go in and start changing things, but some of them have citations.
Sean.Roach (talk) 22:48, 21 June 2022 (UTC)
thread_title:  The chart is full of problems