Talk:Building insulation

Insulation and Air Quality
There needs to be a section on insulation (over insulation) and air quality in the home. The reduction of air quality in the home has been linked to over-insulation. This creates a low level of air exchange which allows contaminants to remain in higher concentrations in the air breathed by occupants. A good deal of research has been done on this subject by Environmental Specialists at Mass General and MIT. —Preceding unsigned comment added by 24.147.110.167 (talk) 16:17, 30 August 2009 (UTC)

Lingering question
''Lingering question: If you install spray foam between rafters, and your attic is part of the conditioned space of your house (not kept cold in the winter), do you still need to leave an air baffle to allow air circulation against the underside of the sheathing?'--82.132.248.198 (talk) 18:34, 30 September 2010 (UTC)

(including fiberglass and rock wool panels, because of the plastic resin used to bind the fibers?) - No there is no resin in insulation.
 * if the foam abuts the underside of the roof then heat will conduct freely between roof and the foam. In summer that means the foam has to deal with the hot underside of the roof rather than just the emitted radiated heat.  In winter you have one less barrier (the air gap) to reduce conduction outward.

Dymonite (talk) 12:59, 19 December 2007 (UTC)

This article can be made shorter by moving portions over to Building Envelope and to Weatherization, Bold textwhich are completely related.


 * Spray foam applied directly to the unventilated rafter bays is called a hot roof. I am not an expert on these roofs but I do know that on a hot roof the roofing material, frequently asphalt shingles, will get hotter than a warm roof (not ventilated) or cold roof (properly insulated and ventilated) which will shorten the life of the shingles. I think this is allowed by the building codes in the U.S. Jim Derby (talk) 03:47, 6 January 2014 (UTC)

How to spell "mold"
Mold is spelled M-O-L-D... there is no U as in M-O-U-L-D. If you need further assistance I can point you to a free online dictionary.
 * Where it will state that "mold" is an Americanization of the British (and international English - everywhere except America) 'Mould'. Miscreant (talk) 08:46, 21 February 2009 (UTC)

"Building insulation" is only Thermal insulation???
"Insulation" covers a not just the 'thermal' but also 'fire' (flame), 'acoustic', 'impact' insulation, etc. that are not reflected on this page at all.

Even in the photo of the hallway, likely there is nothing but the pipework mouldings acting primarily as _thermal_ insulation.

Perhaps this topic should be just merged into 'thermal insulation', or called 'thermal building insulation'. Any thoughts? Miscreant (talk) 11:28, 14 December 2007 (UTC)

Cold climate
In the cold climate section I tagged the statement that windows are the largest source of heat loss as dubious. I also removed the link to passivhaus, because, although it's relevant, it was misleading to have it linked as window heat loss. Windows do usually have some of the largest heat loss per unit area, but since the area is small compared to the roof, it's not clear that the total loss dominates. Certainly it does in some buildings, but the claim that it's typically the largest? Needs a source.

I also removed the discussion of radiation from furniture and humans to the wall. That's all true, but it's not relevant in planning insulation. One can build walls with cellulose, foam, fiberglass, or air, irrespective of how the heat gets from the humans and furniture to the wall. The emissivity of the wall and its effect on thermal comfort, but the discussion here didn't do that issue justice and would be more likely to add confusion than clarity. Ccrrccrr (talk) 00:43, 22 December 2007 (UTC)
 * Actually internal radiation losses are important in insulation. Low-e windows have the ability to  reduce radiant heat transfer.  They work in a different way to double glazing which reduces conductive/convective transfer.  The combined effects are additive. Have you noticed that standing near a window can feel a lot colder on a winter's day.  A lot of this is related because you are not near any interior furnishings/walls to receive radiant heat - therefore net loss out the window from your body.  Conducted losses should not be that great due to  air being a poor conductor.  —Preceding unsigned comment added by Dymonite (talk • contribs) 06:09, 22 December 2007 (UTC)

planning vs. legislation
I goofed by adding deleted material back into planning, not realizing it had moved to "legislation". But the legislation section didn't have anything of substance about legislation, and included discussion of the DOE zip code calculator, which isn't about legislation at all, and included a passive house link. I added that all back into the planning section. I tried to do it with acknowledgment of the stuff that is US focused, without eliminating useful information. The mention of building codes isn't because the planning section is a good place to talk about building codes. It's only mentioned as NOT being a good basis for planning. Ccrrccrr (talk) 02:12, 22 December 2007 (UTC)

Windows
I removed this statement: "Standard glazing is particularly vulnerable to radiative loss because it is relatively transparent to most wavelengths."

It's not transparent to FIR (thermal radiation). It absorbs it. Low-e coatings make it reflect IR instead of absorbing it. Ccrrccrr (talk) 05:01, 23 December 2007 (UTC)

This is wrong. All glass reflects, absorbs, and transmits heat in varying proportion. The original statement was much more correct Miscreant (talk) 18:33, 23 December 2007 (UTC)


 * This is a complicated topic. "Transmits heat" could mean a lot of different things: heat arriving at the window by radiation from room temperature or ambient temperature stuff (about 5 to 20 um wavelength), solar radiation (about 0.2 um to 4 um wavelength), and heat arriving at the window by convection.  But the statement I removed was about "radiative loss" meaning heat leaving the building via radiation.  That means it's radiation from room-temperature objects, not solar radiation, that's relevant.    So we need to find out the transmission of glass in the long-wave thermal IR, or far IR (FIR) range.  Here's one source:  .  All the types of glass they show drop off at 4 um, and are opaque for thermal radiation.  Do you have a conflicting source?Ccrrccrr (talk) 22:54, 23 December 2007 (UTC)


 * On another recent discussion, I noted that windows for thermal radiation need to be made of special exotic materials like ZnS. See, for example, .  A good explanation of how windows work thermally including solar and thermal radiation is this: .  There's no explicit data on ordinary window glass IR transmittance spectra, but it's a great discussion of the issues in general, and the top of p. 7 described thermal radiation being absorbed by the glass, consistent with the other references I've provided.Ccrrccrr (talk) 23:13, 23 December 2007 (UTC)


 * indeed this is a complicated topic. I know is that low-e windows are marketed on the premise they retard long wavelength (far infra-red) generated by internal furnishings and people from being leaving the house but admit short wavelength (near-infra red) that comes from the sun  However, both of these wavelength's are capable of providing heating comfort.  All object radiate heat.  Therefore, radiant energy both enters and exits the building simultaneously - but it is the net gain of energy which is relevant.  On a winter sunless day, the amount of radiant energy entering from outside objects is lower than the energy that exits from the house.  This is also a function of distance and angle.  If a person moves near the window,  a greater proportion of their body is emitting in the window's direction and similarly receiving radiation from the window.  The relative fluxes in between will govern whether they feel warmer or cooler.


 * My apologies. You are right, I was silly and misread the sentance to begin with (as solar radiation, rather than loss through radiation). But now i must disagree in a different light. Obviously all solid surfaces are not initially "transparent" to thermal radiation (unless they have holes or are wafer thin - I'm no chemist, but correct me if i am wrong here), so when we talk about heat transmission through materials as 'transparent', what we are really talking about is the amount of "absorbed" energy which then finds its way through to the opposite side of the glass than it entered into. With solar radiation it is more complex, as sometimes people talk about just the initial 'reflected, absorbed, transmitted', but sometimes they do the same for the absorbed  here, and try to understand whether it is going to get inside, or end up going back outside too... So basically now, I think the first sentancce had some merit to it, even if it was badly worded (while yours is true, but responding to the bad semantics of the original rather than the valid point). Yes? Miscreant (talk) 18:44, 26 December 2007 (UTC)

Topics, what a radiant barrier touches.
The "cold climate" and "hot climate" sections are rapidly growing. There's good materials in there, and in general it's certainly good for Wikipedia to grow, but I'm wondering whether all the topics belong in those sections, or even in this article. Shouldn't discussion of how to deploy radiant barriers go in the radiant barrier section, or better, in the radiant barrier article? Radiant barriers are confusing and hard to explain. It seems we'd succeed better if we explained them in one place, really well. And windows--they are part of the building envelope and are certainly relevant to discussion of insulation, but wouldn't it make more sense to build that content under envelope and have this focus on insulation, and point people to the overarching discussion of envelope on the envelope page?

Once we sort out where we are going to talk about radiant barriers, we'll have to work on that content. I am going to delete one recent addition--the statement that they shouldn't be in contact with a conductive material. What matters is how many airspaces you have. If it's touching some other material, it doesn't matter what. Consider a wall with wallboard, then airspace, then radiant barrier, then plywood (or more likely OSB), then foam insulation, then more plywood. The radiant barrier is in contact with the plywood, which offers negligible insulation value. So you get the thermal resistance of the one airspace with the radiant barrier, plus the thermal resistance of the foam. Now remove the inner plywood, and have the radiant barrier in contact with the insulation. Essentially no difference in performance. If on the other hand, you add airspaces on both sides of the radiant barrier (if both sides of it are low-e), you double the thermal resistnace that you had from the airspace/radiant barrier in the first case. Bottom line is that as soon as you collapse the airspace on one side of a radiant barrier, the effectiveness of that side of the radiant barrier goes to zero, regardless of the material it is touching. If you disagree, that's fine--we can leave that statement out until there is a reputable reference to back it up.Ccrrccrr (talk) 01:19, 24 December 2007 (UTC)


 * You are right that any contact made will negate the actual benefits of having a radiant barrier in the first place. I meant that if it the barrier is going to touch anything at all - rather something with poor conduction than  good conduction.
 * As to how we create sub-articles, it will depend on how widely you define 'thermal insulation'. In a limited way it refers to only bulk insulators.  The problem is that it reduces low-energy design into a set of R-values.  A house that minimizes unwanted heat transfer is more than a set of numbers  attributed to a narrow class of materials.  For legislators, architects and builders this is an appealing way to go but is overly-simplistic and probably counter-productive.

Note about insulating: In this part there is the followoing sentence: " Insulating as tightly and completely as one can while building a house is much easier than retrofitting. For example, if a closed-cell foam gasket is not installed to the sill plate when a house is under construction, there is no way to install it afterwards." I doubt this. Sure it is much easier, but it can be done afterwards. In the Netherlands it is done often Insulation is put above, and a new concrete or woodplate layer is made above it. Or, on a easier but far less insulating way, thin layers of styrofoam with alumininum reflecting coating are used, and a new wooden floor is laid above it. In houses with a full wooden floor, in many cases, at least in the Netherlands, a space of about 40 cm is below it. In many cases that is filled with expanded poloystyre chips, or layers of rockwool or glasswool are hung under de wooden floor, on cords hanging a few inch under de floor itself.

International planning
The "Planning" section seems badly organised and undeveloped. I don't see why the world has to be split into "US" and "International" - this seems unbalanced - especially since Wikipedia is an international site and there is only one country listed in "International".

I'd suggest removing "International" and moving Russia to the same level as the US. I'd also like to suggest that more countries be added to this section.

--School of Stone (talk) 16:53, 12 November 2010 (UTC)

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Cool new use of expanding foam building insulation
... is to make cool videos -- paint + foam => cool stuff to watch. Maybe consider a section on unconventional uses of building insulation.--Tomwsulcer (talk) 00:35, 12 December 2016 (UTC)

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R factor
I came to Wikipedia hoping to find a fairly formal definition of "R factor." Specifically, I'd like to know whether it's defined in a way such that the number billed as "R factor" can be massaged into some dimensionally equivalent fraction of powers of SI units. I searched R factor *per se* on Wikipedia and learned that "[r]esistance transfer factor (shortened as R-factor or RTF) is an old name for a plasmid that codes for antibiotic resistance." The only disambiguation entry linked from there informs me that "R factor" is also part of the terminology of crystallography. Then I come to the present article and there are four instances of the word "factor," none of which reference R-factor. Lori (talk) 15:09, 9 January 2019 (UTC) Oh, I see, I should have searched "R value" instead. Sorry to have bothered anyone. Lori (talk) 00:56, 11 January 2019 (UTC)