# Metric and Imperial

| Posted in Building Code Questions on

In the interests of making the debate on R-values, and U-values more accessible to European readers, or indeed, anyone who lives in a part of the world which uses the metric system (does that include Canada btw?), would it be possible for GBA to compile together a conversion table? Or if there is any available already, to simple link to the same.

I can see from a definitions section in a state of florida building code the following:

Rated R-value of insulation, are in units of h.ft2.degree fahrenheit per BTU, at a mean temp of 75 degrees fahrenheit (24 degrees Celcius).

U-factor, thermal transmittance, units are BTU per h.ft2.degree Fahrenheit.

I have no idea what the ‘h’ in ‘h.ft2’ stands for even.

In the metric parts of the world, U-value is watts per meter squared kelvin.

U-value is the reciprocal of the ‘resistance’ (one divided by the resistance).

The units for resistances are meters squared kelvin per watt, m2k/w.

BTW, a kelvin degree and Celcius degree are the same for all intents and purposes.

The higher the resistance the better, the lower the U-value the better. But no one ever talks about resistance values in Europe. We only talk about U-values.

Sometimes for thermal bridging detail properties, and also for different grades of insulation, with use a measure called resisivity.

It’s units are watts per meter kelvin, w/mk.

When you divide the thickness of your material expressed in meters by the resistivity expressed in watts per meter kelvin, you obtain the thermal resistance of that part of the construction.

Which is expressed in units of meters squared kelvin per watt.

You get a reciprocal of all total resistances, and that gives you the U-value in watts per meter squared kelvin.

But to be honest, when I listen to any of the Green Building Advisor podcasts or read articles, I have no idea what is implied by the R-values or U-values quoted.

I notice that in terms of windows, the U-value is used, rather than the R-value.

In Europe, we would never mix and match our U’s and our R’s.

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### Replies

1. GBA Editor
| | #1

Brian,
h stands for "hour."
U = 1 / R
R = 1 / U

To convert a European U-factor to a U.S. U-factor, divide the European U-factor by 5.678

To convert a U.S. U-factor to a European U-factor, multiply the U.S. U-factor by 5.678

2. Wolfgang Feist | | #2

Go, SI, go. Why? Is it such a fun to even convert inches to feet and to yards and to miles? Dear US friends, why don't you just join the rest of the world? At least one Mars probe would still exist...

3. | | #3

Nice Jab ;--)
Dr Feist

We (US)deserve it

4. Brian O' Hanlon | | #4

Wow, that really does make things a lot easier. I just grabbed the first US building code I could find on my laptop this minute. I think it was some residential building guidelines document published by California Energy Commission back in the late 1990s. Anyhow, it has really nice illustrations.

But for instance, in its table 'Default Fenestration U-values', a fixed non-metal double paned components defaults to 0.57 U-value. It notes, subtract 0.15 for spacers of 7/16" or wider. Subtract 0.05 for products certified by the manufacturer as low-E glazing.

0.57 - (0.05 + 0.05) = ( 'X' multiplied by 5.678) = 2.66 w/m2k

Yeah, I can get my head around that now quite easily. Bearing in mind, this standard is dated the late 1990s. But for then 2.66 w/m2k wasn't bad for a default value in whatever building codes were around then. We currently disallow anything above 2.0 w/m2k in Ireland in 2008 regulations.

Excellent stuff Martin, very much obliged.

I am assuming the R-value of the above window example would be 1/U, so:

1 divided by 0.57 - (0.05 + 0.05) = 2 and a bit.

So we can say an R2 window component, and now I know what Joe Lstiburek means when he runs off these figures in his podcasts, which I find ever so useful. Thanks again.

One note I will add Martin, if I may. Here in Europe our cost benefit analysis is rarely 'bolted on' to our energy efficiency assessment. That doesn't surprise me one bit. Because in Europe, we tend to have separate professionals for design and for cost control - and to be honest, one rather learns to speak the other's language at all. I believe that is the main reason that your federal department of energy can roll out ideas like Energy Saving Performance Contracts for huge public projects.

The approach taken by the European Directive on Energy Performance in Buildings, was that suppliers of the product - the commercial, residential or public building - would be required to publish a sticker on the front of the building, like you find on fridges. Like the one with the nice colours going A to G. By that instrument of informing the market, we hoped that it would affect behaviours by consumers, to incentivise energy efficient building design.

So you can appreciate, that in Europe we took a much less direct approach. It is something I always remark upon when reading the US literature and discussion. You present the dollar cost and the design innovations side by side. It never happens like that over here.

5. Jim Swenson | | #5

Thanks for the great post. As an American I love everything about SI...the problem is that I suck at using it. Hopefully someday metric units will stop looking so Greek, but in the mean time I will have to lean on wiser SI fluent Europeans to help me grasp this system. One particular concept that is difficult for me to get around is the thermal bridge coefficient, which is measured in w/mk. The Passivhaus standard recommends thermal bridge coefficients less than 0.01 W/(mK). In the handy PHPP conversion calculator this translates to a resistivity (r-value) of 14.42 hr.ft2°F/BTU.in. Is this a climate specific recommendation or will the same recommendation hold true in extremely cold climates? Also, can anyone shine a light on how PHPP converted W/(mK) (conductivity) to r-value (resistivity)?

6. GBA Editor
| | #6

Jim,
W/m2-K represents the S.I. system U-factor. If you multiply that number by 5.678, you get a U.S. U-factor in Btu/h-ft2-°F

If you plug that into the R = 1 / U equation, you get the R-value you are looking for.

7. Brian O' Hanlon | | #7

Jim, I have to admit to having a lot of confusion myself with those thermal bridging values as they are called, in w/mk units to rate thermal bridging details. Joseph Little did provide a useful comment on this subject in part 3 of his 'Breaking the Mould' series for Construct Ireland magazine recently. (The article is available from the papers section on his website, spam filter is getting in the way of URL's at the mo)

I need to re-read Little article again to understand the technicalities, but glancing over it he annotates a lot of the simulations of details done using WUFI, with the w/k unit. I think he refers to them as Psi-values. The point that Little makes, is that as U-values for the main wall construction get better, the Psi values are on a sort of sliding scale downwards relatively speaking. That is to say, in a poorly insulated construction, the Psi-values don't come into play nearly so much. But as we get into retrofitting buildings in particular, the Irish regulations at least, don't address this issue of Psi-values that dis-improve, due to the retrofit works to walls.

A recent 'Technical and Practice' article in the Architects Journal in the UK, by Geoff Wilkinson looked at the issues of Part L energy conservation regulations 2010, 2013 and 2016. It is a nice article and at the end of the article he refers to BRE IP 1/06, published by the Building Research Establishment in the UK. I have heard so much about that BRE IP 1/06 and I bought a copy a while back to study. The BRE 1/06 paper isn't much help I have to say, and I wish people would stop referring to it, like it was a source of good explanation. I haven't used the WUFI finite element analysis software or PHPP either. But according to Wilkinson's article in the Architects Journal, under new 2010 Part L energy conservation regulations, there will be a penalty imposed on details, which do not have a certified thermal briding factor. So maybe this ties back to what Joseph Little commented on, in the Construct Ireland article lately.

Lastly, on the 'Green Buildings' section of GBA website, there are links to passive house projects in the USA. The 'Passive House New England' website has an article entitled, '
Using THERM to understand thermal bridging', by Emile on March 30, 2010. So obviously we are getting into 'Imperial units' ground here again - and I don't want to go there, because I don't know what these 'Therm' things that Joseph Lstiburek talks about are. But I imagine, we need to call on poor Martin Holladay again to save the day and offer some means of conversion between Psi-values, thermal bridging factors and 'THERM' units.

8. Brian O' Hanlon | | #8

Joseph Little on thermal bridging where external wall insulation retrofits are concerned.

9. Brian O' Hanlon | | #9

Use of THERM at New England PH.

10. Brian O' Hanlon | | #10

Example to demostrate where the w/k unit comes in. We used to use it in the bad old days to add up the total heat loss from all components of the building fabric, to demonstrate compliance. That is long before we had factored in mechanical and electrical energy efficiencies, and only did a few sums on the fabric itself.

Sill detail Psi-value of 0.04 w/mk - say 4 meters of that detail on a facade.
Jamb detail Psi-value of 0.05 w/mk - say 8 meters on that detail on a facade.
Lintel detail Psi-value of 0.30 w/mk - say 4 meters of that detail on a facade.

Wall construction, U-value of say 0.25 w/m2k, over 10m2.
Windows, U-value of say 0.20 w/m2k, over 4 m2.

0.04 x 4.0 = 0.16 w/k
0.05 x 8.0 = 0.40 w/k
0.30 x 4.0 = 1.20 w/k
0.25 x 10.0 = 2.50 w/k
0.20 x 4.0 = 0.80 w/k

Total of 5.06 w/k over 14.0 m2, implied a total aggregated U-value of 0.36 w/m2k.
Or an Imperial U-value of 0.36 / 5.678
Equals 0.06 BTU per h.ft2.degree Fahrenheit.

R-value equal to 16.0 h.ft2.degree fahrenheit per BTU, rounded down from 16.6.

So you can see in my example above, if I ignore thermal bridging altogether, or I don't account for it correctly as Joseph Little described in his Construct Ireland article about retrofitting masonry structures, then I have a U-value for the entire facade (windows & walls combined) of,

0.24 w/m2k

Which gives me an Imperial U-value of 0.04 BTU per h.ft2.degree Fahrenheit.

Or an R-value for the facade of 25 h.ft2.degree fahrenheit per BTU.

Whoa! See the difference? You can see now why the British Part L energy conservation regulations insist on those certified junction details. Joseph Lstiburek and John Straube is right of course. You cannot rely on hitting the specified R-values, unless you account for things like convection within the structure itself. We are begining to pressure test our structures here, with just the external weathering layer - before the internal air barriers, sheet rock etc are installed - to try and improve theoretical R-value performances in Ireland. But I would imagine, that still only happens on certain jobs, where the builders really want an energy efficient home. At the moment, many residential property transactions are taking place in Ireland, without the influence of the 'Building Energy Rating' sticker which I talked about above, which is meant to act like the same on a well made refrigerator appliance. All the best, BOH.

11. Interested Onlooker | | #11

Is the thermal bridge coefficient in W/(mK) or W/(m.K) ?

12. Brian O' Hanlon | | #12

Correction:

Oops! You would know I am a bit rusty on all of this. Scratch all entries of 0.2 w/m2k for the windows above. That should have been 2.0 w/m2k. Basically, with 4.0 meters squared of 2.0 w/m2k window glazing and the 10.0 meters squared of wall, you wouldn't get anywhere near an R-16 or R-25 facade.

Just pretend in my example above, that I it was a facade with no windows at all, and it had two different types of wall construction, one slightly better insulated than another. Say for example, a basement wall area and the timber frame wall area sitting above. In that case, the example above, can still serve to illustrate my point above thermal bridging factors as I describe. Apologises again, to all concerned for any confusion I caused.

13. Brian O' Hanlon | | #13

@ Onlooker,

W/(m.K)

14. Jesse Thompson | | #14

Jim,

Here's an attempt to explain thermal bridge math:

The psi value is the thermal bridge coefficient, it's a factor that allows you to calculate the effect that thermal bridge has on a simply calculated joint's R (or U) value, that's why it's a measurement per linear foot.

The process would be to calculate the simple R of the joint as measured by the overlapping geometries of the wall R and the floor R (or roof, or whatever), then calculate the true R of a complex joint using a program like THERM (http://windows.lbl.gov/software/therm/therm.html), and then subtract the actual R value of the joint from the estimated R value of the joint. The coefficient is then the difference between the simple estimation of the R of the joint and the actual, so you have a coefficient to apply to any of those joints and add accuracy to your model.

A Thermal Bridge Coefficient can be positive or negative. Some joints are worse insulated than when calculated simply (typical slab on grade, frost walls, etc), some are better (two thick thermally broken walls meeting correctly have a great R value along the diagonal).

See here for more explanation by David White, PHPP & THERM master: http://www.rightenvironments.com/free_downloads/091129%20Thermal%20Bridge%20Analysis%20for%20the%20PHPP%20v3.pdf

15. Brian O' Hanlon | | #15

Jesse,

Thanks for that. Acording to the BRE's SAP manual, in the appendices they provide some default Psi-values for surveyors of existing structures. A normal corner has a Psi-value of,

0.09 w/mk

An inverted corner, on the other hand, has a Psi-value of,

-0.09 w/mk

That is due to the extra build up of material at an inverted corner, while at a normal corner you have more exposed area. SAP stands for the 'standard assessment proceedure' btw, and it is what we use to come up with those A to G, energy rating labels which all buildings need to have in Europe.

For everyones' interest, this is interesting:

With the regulation standard 2.0 w/m2k windows, the R-value is above 7.0.

Accounting for thermal bridges around the windows using default Psi-values in w/mk as I listed above, and the 2.0 w/m2k windows, I get an R-value of well below 7.0.

But you will notice it doesn't make the dramatic difference - as in, R-16.0 to R-25. The results I calculated, when I didn't have the big 4.0 m2 of U = 2.0 w/m2k window in the facade.

So it does reinforce the point that Joseph Little was trying to make. When you go to higher insulation values and higher level components, you really do need to watch out for thermal bridging.

Note:

That is not quite the point that Joseph Little was making. His point was that with retrofitting existing walls with external insulation, the actual Psi-values themselves can alter significantly from the defaults which we use from the Technical Guidance documents here. Such as the 0.04 w/mk Psi-value for cill details where you put a little bit of foam behind a concrete sill. Little's point is that, when you add exterrnal insulation and not remove the existing cills, and replace with a better detail, and push out the window component to the plane of the insulation, then the previous default 0.04 w/mk Psi-value becomes much, much worse.

16. Brian O' Hanlon | | #16

Here is another interesting wrinkle in all of this debate. I checked over a PowerPoint presentation I had on file: Rob Dumont, Saskatchewan Research Council, TECA Presentation, Vancouver, B.C., December, 2007. I notice that Rob has combined SI R-values and Imperial R-values on one of his slides. I have done the calculations and it works out, as Rob has said here on the slide.

Thermal Resistance Values for the Factor 9 Home

• Attic – R80 (RSI 14)
• Walls – R34.5 (RSI 6.1)
• Basement Walls – R50 (RSI 8.8)
• Basement Floor – R11.4 (RSI 2)

Now I have to admit, this is the first time I have ever seen RSI units quoted before. As I said in the original post above, in Europe we never talk about R-values. We only talk about U-values. Martin Holladay is very welcome to his point of view though, that it is strictly speaking a 'U-factor', and perhaps it would be nice if everyone in Europe started talking about U-factors rather than U-values.

Just for academic interest again, Jim was right. There is a conversion tool, if you check out the last tab in the free PHPP demo Excel file, which I just downloaded from BRE's website in the UK. I will have a better look at the PHPP calculator when I get around to it.

17. Riversong | | #17

Wolfgang Feist: "Dear US friends, why don't you just join the rest of the world?"

Though this is hardly the reason that the US stands virtually alone in persisting with "Imperial" units (it's more likely because we're now the sole empire), there is a significant value to such "analog" measurement units.

While the goal of IT has long been to create a computer as versatile in every way as the human brain, it seems the trajectory of civilization is to turn the human brain into a digital computer.

The brain (along with the rest of our human paraphernalia) evolved in a sensory environment in which the primary measuring "implement" was our own body - hence "foot" (the length of a foot) and "inch" (the length of a finger joint), and "span" (the stretch of two arms), and later "chain" and "rod" and "furlong" (the length of a plowed furrow) as simple technologies extended our reach.

The reason that metric (base ten) units have become commonplace is that we live in an increasingly artificial world of numbers which alienates us from the very ground of our being and sustenance. One outcome of this mindset is the measuring of value only in terms of monetary units and the dismissal of anything which doesn't have a market price (including traditional women's work and the natural ecology).

So, while SI units make "sense" for abstract computation, the traditional units truly make sense to our senses, our bodies and our earthly environment.

18. Riversong | | #18

Brian,

The reason we 'Mericans use both R-value and U-value ("factor" and "value" are interchangeable) is that R-value is additive (when totaling the thermal resistance of multiple heterogeneous layers) and U-value is averageable (when calculating the overall heat loss rate from a non-homogeneous wall assembly).

And the reason that RSI units that are in W/m²·K are converted to R units in BTU/sf·hr·°F (including time) is that a watt is a unit of power (energy over time) while a BTU is a unit of energy (heat), making the BTU/hour a more intuitively understood unit of heat loss than the SI watt. And it's a more intuitive unit because it evolved from direct sensory experience rather than mere mental manipulation.

19. | | #19

I think Robert is stretching it a bit when he says that a BTU is more 'intuitive' than a Watt (very glad to see him back, by the way). They are both pretty abstract concepts. I think the reason BTU's are preferred this side of the pond is because they give us such big numbers, and Americans LOVE big numbers: they'll take 30,000 BTU over a measly 9kWH any day.

Digression: I notice that US news sources dropped the cap on the BP well at 15,000 lb - the BBC was content with a mere 7.5 tons.

20. Riversong | | #20

James,

A BTU is the heat of one wooden kitchen match - very intuitive.

But what I said is that heat loss is more intuitively understood in terms of energy per hour (heat flow rate) than in terms of power (which hides the time function).

21. Brian O' Hanlon | | #21

Robert, I agree with you on the intuitive nature of the Imperial system. In terms of length units, (both inches and miles), area units (acres or sq. feet), weight units (pounds mainly I think of).

If you tell me that energy is intuitive in BTU's, I will more than buy into that. The minister for energy when trying to explain something at a parlimentary meeting recently, came up with an excellent analogy to explain a teaspoon of oil. It is equivalent in its energy content to 'X' hours of labour by an adult human. Fancy that! I forget exactly what 'X' was, but it was several hours.

22. Brian O' Hanlon | | #22

But when we try to compare PV panel to deep retrofit, we are back into using metric figures again. That is something I do find interesting. It is like the way tyre specfications for cars - have the depth of threads on the rubber in metric, and the diameter of the wheel rims in Imperial. Or some odd combination along those lines. Nicholas Negroponte of MIT media labs used quote it, as an example. We have something similar in PV arrays - which is already comparing electrical energy to thermal energy - and then you mix SI and Imperial units on top of that. For instance, Martin's article recently on deep retrofits:

The deep-energy retrofit would save 84,000,000 BTUs per year, which equals 24,612 kWh.

You must divide the 84 million BTU's by 3412, to get the 24,612 KWh's. So you see when I read a GBA article, I am confronted with a mine field to navigate through. I can only imagine what it is like for global committees on climate change!

23. Riversong | | #23

Sustained human work output in agriculture is about 0.1 HP or 0.074 kW.

A gallon of gasoline (petrol to you Brits) is the work equivalent of 500 person-hours, and a barrel of crude oil is equivalent to 23,200 person-hours (this doesn't consider conversion inefficiencies, which are considerable).

So it's no wonder that our short-lived exploitation of fossil fuels (ancient sunshine) has allowed us to provision a six-fold overpopulation of the earth (the first "green revolution"), with a significant portion living at a ridiculously high level of material affluence. But, since we are now approaching the end of the fossil fuel age, we are experiencing global collapse at an accelerating rate - both economically and ecologically.

Now, in the midst of the second "green revolution", we are still relying on technological and petroleum-based solutions (e.g. foam insulation and sophisticated ventilation systems) to what is in reality a crisis of culture and mentation. And we will inevitably discover that this second "green" movement is as wrong-headed as the first.

"We cannot solve problems with the same mindset that created them." - Albert Einstein

24. Interested Onlooker | | #24

I believe that what North Americans refer to as gasoline is also referred to as petrol in Ireland. ;-)

25. | | #25

"I can only imagine what it is like for global committees on climate change!"

The global scientific community including its US membership has used SI units exclusively for many years. American engineers on the other hand have largely stuck to foot-pounds, mils and the like, making international collaboration sometimes comically difficult.

There's nothing 'intuitive' about the amount of the quantity of heat produced by a matchstick any more than the quantity of heat required to raise the temperature of a certain amount of water. Both are interesting illustrations, the second at least gives a datum actually quantifiable to reasonable accuracy with simple equipment: a thermometer and a measuring jug. If I were a science teacher I know which I'd choose.

But all measurement units are ultimately somewhat arbitrary. I recall a brickmason on an English building site back in the early eighties when the UK construction industry was going through its conversion pangs: "Why should I get excited about going from a measurement system based on an English king's foot to one based on how far Napoleon could piss?"

26. Brian O' Hanlon | | #26

Robert says,

But, since we are now approaching the end of the fossil fuel age, we are experiencing global collapse at an accelerating rate - both economically and ecologically.

All the more reason, a rational response would be, that networks of green builders on both sides of the pond, should try to share their ideas - and even criticise each other. Some of the criticism of the Europe school of green building, by the north American camp, has been really refreshing to listen to. And visa versa. We talk a lot here in Ireland about my generation (I'm mid thirties in age), of having adopted the 'American style of living'. That is, where we drive half ways across the island of Ireland each day to go to work. That level of movement by the population when I was a mere young fella, was unheard of. But since I have grown up, it has increasingly become the norm. As green party parliment member and architect, Ciaran Cuffe said at an event I attended:

We have invested a huge amount of resources in figuring out ways to get from 'A' to 'B' faster. But we haven't figured out how to make either 'A' or 'B', a nice place to be, when you arrive there.

I would like some day to read an article at Green Building Advisor, by one of the Irish green party members. They have some genuinely interesting observations to make - which you north Americans might find equally interesting to think about. The real prize has to go to my old school friend though, who purchased his first four-wheel drive vehicle at seventeen. When we stop at a petrol station he says, I need to some more fruicy-juicy. Sometimes, I am so ashamed of my generation. Best of luck, BOH.

27. Brian O' Hanlon | | #27

@ James Morgan,

Excellent James. I like it. BOH.

28. Riversong | | #28

James Morgan: "If I were a science teacher I know which I'd choose."

Well I AM a teacher of building science and, when I use the matchstick analogy, the eyes light up with recognition. When I speak of raising a pound of water 1°F, the eyes glaze over. The less abstract and more tangible our definitions and illustrations, the more comprehension (literally: to grab by the hand).

BRIAN O' HANLON: "All the more reason, a rational response would be, that networks of green builders on both sides of the pond, should try to share their ideas - and even criticise each other."

I'm all for cross-fertilization and constructive criticism. But let's be wary of "rational" responses, since it's reason and its manifestations in science and technology which has so limited our perspectives and responses to have led us into the global stew we're now trying to extricate ourselves from.

And, while global instant communication might have some benefits, it also has some very serious liabilities - including both an overload of information and the confusion between information and knowledge, as well as an exponential increase in terrestrial electro-magnetic "noise" (which seems to be the cause of honey bee colony collapse syndrome and almost certainly has deleterious effects on our own biology.

If we are to approach cultural sustainability, it will be through a revival of intuition, instinct, common sense, and the wisdom of the heart (which neurocardiology has discovered is our primary and most powerful resonator, EMF generator, communicator and homeostasis control center).

29. Brian O' Hanlon | | #29

Robert says,

I'm all for cross-fertilization and constructive criticism. But let's be wary of "rational" responses, since it's reason and its manifestations in science and technology which has so limited our perspectives and responses to have led us into the global stew we're now trying to extricate ourselves from.

I'll certainly take that thought with me Robert. Thanks for sharing it with us all. I didn't know about the honey bee and EMF connection, but I'm certainly glad you brought it up. BOH.

30. Riversong | | #30

BOH: bat outta hell?

31. | | #31

OK Robert, I'll give you the match. I do enjoy the image of a few thousand matches sitting under a heat exchanger. Then burning out.
I also agree with your comment on the importance of intuition and instinct: supported, I would add, by patient observation, long experience, and paying attention to the legacy of those who came before us. I admit to being a little jumpy when people talk about 'common sense' - so often a cover for prejudice and received opinion, I'm afraid, an excuse for the non-enquiring mind, Not that I would ever accuse you of such failings, Robert!
I too relish the notion of cross-cultural and international sharing of insights, experience and knowledge. Just so long as we remember that understanding LOCAL conditions (climate, culture, economy) is paramount in good environmental design. Many of the discussions here in GBA are dominated by northern US climate concerns; we in other parts must pass those wisdoms through the filter of our own knowledge, intelligence and understanding, even more when the contributions come from Germany, Ireland, Indonesia, or Australia. And vice versa.

32. | | #32

I miss "Bat Out of Hell"

33. Riversong | | #33

You mean Bat out of Hell by Meatloaf?

34. Riversong | | #34

Now that you've dredged (that's a nice sensual term) this thread back up from the depths of the Atlantic ocean, I'd like to reflect more on the idea of "common sense", which for James evokes prejudice or received opinion. I think that perception of "common sense" is indicative of how far we've strayed from that most basic and essential of human attributes.

As another example, when I define a joule (the SI unit of energy) as "the amount of energy required to produce the power of one watt continuously for one second; or one watt second (W•s)", there is no glimmer of understanding among the students. But when I then describe and depict on screen "or approximately the amount of energy required to lift a small apple one meter", the abstract concept translates into something sensual and recognizable to "common sense".

Merriam-Webster uses the phrase to refer to beliefs or propositions that most people would consider prudent and of sound judgment, without reliance on esoteric knowledge or study or research, but based upon what they see as knowledge held by people "in common". Thus "common sense" (in this view) equates to the knowledge and experience which most people already have. Another meaning to the phrase is good sense and sound judgment in practical matters.

My contention is that, before we lost our connection with the land and with the daily, physical labor of life, common sense was far more common and far more efficacious in both survival and constructive human interaction.

According to Wikipedia: Common-sense ideas tend to relate to events within human experience, and thus appear commensurate with human scale. Humans lack any common-sense intuition of, for example, the behavior of the universe at subatomic distances or of speeds approaching that of light.

Both Aristotle and Locke understood common sense as the inner and innate capacity to synthesize disparate sensations into a single whole impression, much as a prey animal can "sense" a predator without having to intellectually analyze the inputs of the various senses.

The truth is that if a prey animal spent time in intellectual analysis it would be lunch before it could figure out the nature of the danger or how to react to it. Similarly, today we humans spend so much time in intellectual and abstract thought that we largely miss the fact that we are now our own worst enemies (predators) and have lost the "common sense" capacity for right action in response to danger (instead doing more of the same).

The metric system has helped make the world more abstract and mathematically-perfect, perhaps, but has deprived us of the common sense understanding of the world we actually live in. I understand the length of my foot (I use it to step off a rough distance at a building site), and the length of my stride (I use it to quite accurately measure long distances on the land, including in Search & Rescue, more reliably than a GPS).

When I teach knots and rigging, I use the width of a human palm to describe how long the tail of a secure knot should be. The various anthropopic and anthropomorphic units of measurement that became the Imperial System only because the British exported it along with their navies offer a more common sense approach to taking the measure of our world and being connected to it on a visceral level. The loss of that sensual connection to the earth has contributed to our current global malaise.

For those who would like a glimpse of the world we have lost and must regain, I would highly recommend the book, The Spell of the Sensuous: Perception and Language in a More-Than-Human World by David Abram.

From Publishers Weekly:
How did Western civilization become so estranged from nonhuman nature that we condone the ongoing destruction of forests, rivers, valleys, species and ecosystems? Santa Fe ecologist/philosopher Abram's search for an answer to this dilemma led him to mingle with shamans in Nepal and sorcerers in Indonesia, where he studied how traditional healers monitor relations between the human community and the animate environment. In this stimulating inquiry, he also delves into the philosophy of phenomenologists Edmund Husserl and Maurice Merleau-Ponty, who replaced the conventional view of a single, wholly determinable reality with a fluid picture of the mind/body as a participatory organism that reciprocally interacts with its surroundings. Abram blames the invention of the phonetic alphabet for triggering a trend toward increasing abstraction and alienation from nature. He gleans insights into how to heal the rift from Australian aborigines' concept of the Dreamtime (the perpetual emerging of the world from chaos), the Navajo concept of a Holy Wind and the importance of breath in Jewish mysticism.

"Only as the written text began to speak would the voices of the forest, and of the river, begin to fade. And only then would language loosen its ancient associations with the invisible breath, the spirit sever itself from the wind, the psyche dissociate itself from the environing air," writes Abram.

35. | | #35

"Merriam-Webster uses the phrase to refer to beliefs or propositions that most people would consider prudent and of sound judgment, without reliance on esoteric knowledge or study or research, but based upon what they see as knowledge held by people "in common". Thus "common sense" (in this view) equates to the knowledge and experience which most people already have. Another meaning to the phrase is good sense and sound judgment in practical matters."
Good definition, which includes the very element that make me jumpy - 'knowledge held by people in common', which history tells us has always been hugely susceptible to manipulation, distortion and wishful thinking. At various times in our history it was considered common sense that the arcane religious incantations of the Jews were intended to bring down plague and drought on their Gentile neighbors (how else could they be so successful), and it was common sense that burning them at the stake would be an expedient way to deal with the problem. It's common sense to a majority of the current U.S. of the population that concern about irreversible climate change is alarmist and that we can go on burning fossil fuels without consequence. It's common sense that people who rush out on Black Friday to buy s**t they don't need or want at marginally discounted prices are making smart financial choices, and common sense that a happy meal at McDonalds is good value for our kids' breakfast.

I am aware Robert that you pine for a time and place where 'common sense' really does reflect the teachings of our own innate deep wisdom. I don't see that happy place coming to mainstream culture anytime soon, and while that is true I will continue to cast a skeptical eye on what 'knowledge held by people in common' has to tell us.

36. Riversong | | #36

James,

You continue to confuse many things.

First, Jews weren't burnt at the stake - that was witches - they were burnt in ovens, which was more energy-efficient and environmentally sound. And the plagues, as everyone who read the bible knew, were brought down by Jehovah, not by earthly incantations. The Jews, as everyone knows, were only good at making money (satire, in case anyone misses it).

And you make the "common" mistake that history began with the start of civilization, which was the beginning our demise, not our ascension, as a species. For 99% of human history on the planet, we were hunter-gatherers or simple agrarians with enough "common sense" to survive ice ages and huge predators and travel across the globe without leaving any garbage behind.

In terms of current or recent historical periods, you confuse common prejudice with common sense. Even at times when commoners harbored unwarranted prejudices (often inculcated by the aristocracy and the Church for their own benefit), they often had "good sense and sound judgment in practical matters".

And let's not forget that the modern "public relations" industry, also known as advertising or propaganda, is quite recent - having been virtually invented by Sigmund Freud's nephew Edward Bernays to convince Americans to get involved in the first European conflagration (WWI) and then to sell cigarettes and cars using appeals to emotion, ego and id (subconscious desires and conditioning principles).

Add to that the goal of mandatory public education of dumbing down the common folk (yes, that was the articulated desire of the aristocracy which funded public education in the US, modeled after the Prussian system), and the carefully nurtured race-baiting and immigrant hatred that keeps the lower classes divided against themselves - and we have the perfect conditions for the easy dissemination and assimilation of dysinformation.

Finally, you missed the most important part of the definition of common sense: the knowledge and experience which most people already have – which means before education, before indoctrination, before propaganda, before advertising, before multi-million dollar dysinformation campaigns – innate and fundamental to our evolution as a species. That, like our DNA, is what we humans hold in common, but has been overlaid with so much nonsense as to be difficult to access without effort. And I think it's true that the more education we have, the less common sense remains available.

37. GBA Editor
| | #37

Robert,
Although you are wise and all-knowing, others aren't. How is an individual to determine the difference between common prejudice and common sense?

Science is one way. Perhaps you can suggest another.

38. Riversong | | #38

Here comes Martin Holladay, who censures people for making ad hominem arguments and starts with this sarcastic comment: "Although you are wise and all-knowing, others aren't".

I've never claimed to be omniscient, and am happy to leave that attribute to the Creator of the Universe (or to the Universe itself, which is self-creating). But quantum theory suggests that all the "knowing" that the Universe contains (or, rather, is made of) is available all the time to every aware being (something that shamans and mystics have always known). The Universe is composed of organized energy (knowledge), with infinite potential for manifestation and infinite opportunities for us to tap into that limitless field of knowledge (Rupert Sheldrakes' Morphic Field, or the Quantum Field or Einstein's Field: "There is no place in this new kind of physics both for the field and matter, for the field is the only reality.").

I have, however, gleaned much knowledge from tapping into that Field and have gained a certain amount of wisdom by drinking from the ageless fonts of the great wisdom traditions and from standing outside the conventional paradigm and looking at it from a much broader and critical perspective (which precious few are willing to do).

The simple answer to your question – "How is an individual to determine the difference between common prejudice and common sense?" – is: by using common sense (which, I'll agree, is perhaps the least common of the innate human senses today).

As the Webster definition makes clear (why are others missing this?), common sense is "the knowledge and experience which most people already have." And I would add "but have forgotten because of the enormous overlay of culturally-prescribed beliefs, distortions and misinformation".

I have led dozens of people, young and old, into a pathway of discovery of these truths that we already know – which are part of our DNA – in a ritual process called Vision Quest. I've even done this in a 45-minute experiential exercise as part of my Thinking Like a Mountain class at Yestermorrow Design/Build School and offered it to members of the Green Mountain Club as part of a Silent Meditative Hike.

Civilization, and particularly modern Western culture, has dismembered us from the Web-of-Life and from authentic community and fundamental knowledge (common sense). So it often requires focused and guided ritual activity (which means to step outside of conventional reality) to help us re-member ourselves (and our common sense).

But, to the degree that common sense is "good sense and sound judgment in practical matters", I think that a majority of people who still work close to the land or in various crafts and simple trades, and most indigenous people, still have a great deal of common sense.

Education, unfortunately, derides and denigrates this common sense and substitutes bodies of specialized information and modes of rational thought that undermine our native abilities and wisdom. Science is the least likely pathway to common sense, since it is based on abstraction, analysis (taking things apart) and mathematical certainty (which, according to Gödel's incompleteness theorems, is an oxymoron). In fact, I would dare to say that science has made us more ignorant than any other human endeavor.

" The supreme task of the physicist is to arrive at those universal elementary laws from which the cosmos can be built up by pure deduction. There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them. "
- Einstein, "Principles of research", 1918

" ... as far as the propositions of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. ... "
- Einstein, "Geometry and Experience", 1921

39. GBA Editor
| | #39

Robert,
I apologize for my comment, which was glib and unnecessary. But I was trying to make a point: namely, that your logic is circular. You use common sense to tell the difference between common sense and common prejudice. My neighbor does the same, and concludes the burying a toad in the backyard under a full moon cures warts, and that Jews are dangerous neighbors who plot against the gentiles.

It's not enough to say, "Just use common sense to determine what is common sense."

40. | | #40

Robert, you display a startling ignorance concerning the fate of thousands of Jews and other 'heretics' at the hands of the Inquisition:
"In the beginning, the Inquisition dealt only with Christian heretics and did not interfere with the affairs of Jews. However, disputes about Maimonides’ books (which addressed the synthesis of Judaism and other cultures) provided a pretext for harassing Jews and, in 1242, the Inquisition condemned the Talmud and burned thousands of volumes. In 1288, the first mass burning of Jews on the stake took place in France.

In 1481 the Inquisition started in Spain and ultimately surpassed the medieval Inquisition, in both scope and intensity. Conversos (Secret Jews) and New Christians were targeted because of their close relations to the Jewish community, many of whom were Jews in all but their name. Fear of Jewish influence led Queen Isabella and King Ferdinand to write a petition to the Pope asking permission to start an Inquisition in Spain. In 1483 Tomas de Torquemada became the inquisitor-general for most of Spain, he set tribunals in many cities. Also heading the Inquisition in Spain were two Dominican monks, Miguel de Morillo and Juan de San Martin.

First, they arrested Conversos and notable figures in Seville; in Seville more than 700 Conversos were burned at the stake and 5,000 repented. Tribunals were also opened in Aragon, Catalonia and Valencia. An Inquisition Tribunal was set up in Ciudad Real, where 100 Conversos were condemned, and it was moved to Toledo in 1485. Between 1486-1492, 25 auto de fes were held in Toledo, 467 people were burned at the stake and others were imprisoned.......

....The last auto de fe in Portugal took place on October 27, 1765. Not until 1808, during the brief reign of Joseph Bonaparte, was the Inquisition abolished in Spain. An estimated 31,912 heretics were burned at the stake, 17,659 were burned in effigy and 291,450 made reconciliations in the Spanish Inquisition. In Portugal, about 40,000 cases were tried, although only 1,800 were burned, the rest made penance."

Though the Inquisition was a resoundingly successful exercise of centralized Papal power and authority it was enabled to continue for over six hundred years by the 'common sense' acquiescence of the general population. Well before the time of Edward Bernays.

What confuses me even more though is the anti-science rant from one who consistently offers soundly science-based construction wisdom in this forum. WTH????

41. Riversong | | #41

James apparently cannot differentiate between satire (even when it's labeled as such) and historical treatise.

And he also uses biased sources for his rendition of history.

Jewish historian Steven Katz said of the Medieval Inquisition that "in its entirety, the thirteenth and fourteenth century Inquisition put very few people to death and sent few people to prison; 90 percent of its sentences were canonical penances" (The Holocaust in Historical Context, 1994). Henry Kamen gives the number of about 2,000 executions in persona in the whole Spain up to 1530. Estimates vary, but it appears that perhaps 2% of all those accused of heresy (which is what the Inquisition prosecuted, including the false conversion of Jews) were actually killed. In other words, during the centuries of the Inquisition, the total number killed was perhaps a third of those we incinerated during the two weeks of Shock & Awe in Baghdad, for which no one sheds a tear of moral indignation.

And Martin, like James, confuses common superstition and prejudice with common sense - clearly not using his own common sense to differentiate between the two. He claims that my logic is circular, which it cannot be since I was not using logic (a purely intellectual pursuit), but common sense (which precedes the intellect, and without which we would not have the luxury of armchair ruminations).

Martin, however, is quite right when he states: It's not enough to say, "Just use common sense to determine what is common sense", since (as I thoroughly explained) most of us have lost touch with that most fundamental of all human modes of knowing. However, if we still had any amount of common sense available to us, we would not suffer the absurd confusion of this salutary quality with the baser qualities of modern humanity (inculcated and reinforced by our "advanced" civilization).

James still refuses to recognize that the dictionary definition of common sense has to do with "good sense and sound judgment in practical matters" - which hardly encompasses complex social, political and religious institutions of power, wealth and control – which, of necessity, has always relied on misinformation and manipulation of the masses for the good of the few.

And he remains confused about I can offer an "anti-science rant (sic)" when I "consistently offer soundly science-based construction wisdom in this forum" - even though I presented two quotes from perhaps the most famous scientist of all time - Albert Einstein - stating emphatically that it is not logic or mathematical certainty that brings us any closer to the nature of the universe, but rather "only intuition, resting on sympathetic understanding of experience" - in other words: Common Sense.

Native Americans understood that the intellect is but one arrow in the quiver, to be taken out and used when appropriate and otherwise to be left sheathed. We moderns have fallen victim to the illusion that intellect is the highest and most powerful quality of the human being and should be used in all cases for any purpose – and that has been our downfall.

I use building science where it's appropriate – just as Einstein used that language to "prove" to others what his intuition had taught him. But building science cannot answer the fundamental moral or existential questions that will either save or damn us as a species, which is why we need to use our common sense when it comes to living sustainably on earth.

42. | | #42

I am as big a fan of satire as anyone, but satire is usually held to be funny. Nothing much funny about bonfires versus ovens. Nor about the numbers gaming. 2% of the hundreds of thousands persecuted and tortured by the Inquisition over six centuries is hardly something to dismiss with a facile joke. Those who were not burned to death were terrorized into submission. "Common sense" during that reign of terror said go with the flow, don't make waves.

"building science cannot answer the fundamental moral or existential questions that will either save or damn us as a species" - heartily agreed - "which is why we need to use our common sense when it comes to living sustainably on earth"
If only the common sense of which you speak were indeed the knowledge held by the people "in common". Apparently some 40% of Americans currently bask in the 'knowledge' that Saddam Hussein was responsible for the 9/11 hijackings.

43. | | #43

Don't get me wrong, I'm well aware of the way in which we can get so wrapped up in our preoccupations with minutiae that ordinary clarity of perception goes out the window: "king's new clothes" syndrome. There are plenty of examples in this forum IMO - exercising ourselves to extract the last calorie of heat energy from a dryer vent, for example, when the common sense of which you speak tells us to bypass the mechanical dryer and simply hang the clothes out to dry. Unfortunately that common sense is very far from the common knowledge of the culture: and the phrase is so often used as a cover for actions and attitudes that make no sense whatsoever.

44. Riversong | | #44

Unfortunately that common sense is very far from the common knowledge of the culture

Which is precisely why we must "return to our senses", get out of our heads, and stop allowing ourselves to be "led by the nose".

Let's not forget that it was "Common Sense" (by Thomas Paine, the most read publication in American history, and originally tilted "Plain Truth") that moved our progenitors to break with the shackles of the past and struggle for freedom against the greatest power on earth.

Today, the greatest power on earth is fear coupled with desire and bound to ignorance, which enslaves us more surely than any Empire because it enslaves our hearts, minds and souls.

Unless we literally lose our minds, we have no hope of finding our way back to the Garden which was our birthright and our home.

Manifesto: The Mad Farmer Liberation Front

by Wendell Berry

Love the quick profit, the annual raise,
vacation with pay. Want more
to know your neighbors and to die.

Not even your future will be a mystery
any more. Your mind will be punched in a card
and shut away in a little drawer.

When they want you to buy something
they will call you. When they want you
to die for profit they will let you know.
So, friends, every day do something
that won't compute. Love the Lord.
Love the world. Work for nothing.
Take all that you have and be poor.
Love someone who does not deserve it.

Denounce the government and embrace
the flag. Hope to live in that free
republic for which it stands.
Give your approval to all you cannot
understand. Praise ignorance, for what man
has not encountered he has not destroyed.

Invest in the millenium. Plant sequoias.
Say that your main crop is the forest
that you did not plant,
that you will not live to harvest.

Say that the leaves are harvested when they have rotted into the mold.

Call that profit. Prophesy such returns.
Put your faith in the two inches of humus
that will build under the trees
every thousand years.

Listen to carrion -- put your ear
close, and hear the faint chattering
of the songs that are to come.
Expect the end of the world. Laugh.
Laughter is immeasurable. Be joyful
though you have considered all the facts.
So long as women do not go cheap
for power, please women more than men.

a woman satisfied to bear a child?
Will this disturb the sleep
of a woman near to giving birth?

Go with your love to the fields.
in her lap. Swear allegiance
to what is nighest your thoughts.

As soon as the generals and the politicos
can predict the motions of your mind,
lose it. Leave it as a sign
to mark the false trail, the way
you didn't go.

Be like the fox
who makes more tracks than necessary,
some in the wrong direction.
Practice resurrection.

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