Thanks so much! Please write me back
Merritt

http://www.youtube.com/user/MDESIGNSGLOBAL

or

http://www.mdesigns.net

Thank you so kindly.

I think it is gorgeous. And I love the Japanese influence. Thank God for someone with imagination!

R-value is a term predominantly used in the building industry to rate the insulative properties of construction materials.

It is derived from the U value (see below). The higher the R value, the greater insulation.

The relationship between U-value or R-value and thickness is not always exactly linear and therefore its value cannot be precisely extrapolated for a material of different thickness, but assuming a linear relationship is often adequate. In any case, R values of adjacent materials can be added to determine a final R value of the entire construction e.g. R value(brick) + R value(fibreglass batt) + R value(plasterboard) = R value(total)

The SI unit for R-value is K·m²/W.

The imperial unit for R-value is ft²·°F·h/Btu. The conversion factor is 1 ft²·°F·h/Btu ≈ 0.1761 K·m²/W, or 1 K·m²/W ≈ 5.67446 ft²·°F·h/Btu.

To avoid confusion sometime the nomenclature ‘RSI’ is used to denote the SI form of the value. In contrast, the imperial unit is often written as R–31.4. To add to the chaos, some countries that employ the SI system (e.g. New Zealand) retain the R but incorporate a dash e.g. R–5.53. One tenth of an RSI is called a tog.

It is important to realise that R-value only relates to heat transfer from conduction only. Correctly, it ignores the effect of heat transfer from radiation and convection. Confusion can be created when building products quote an ‘equivalent’ R-value for radiative heat transfer . R-value similarly do not consider the effect of convection. For instance, air infiltration of windows and doors can be a significant source of convective heat transfer compared to walls, roofs and floors.

R-value should also not be confused with the intensive property of thermal resistivity and its inverse, thermal conductivity. The SI unit of thermal resistivity is K·m/W. Thermal conductivity assumes that the heat transfer of the material is linearly related to its thickness.

Contents
[hide]

* 1 U-value
* 2 Insulation Aging
* 3 Example values
o 3.1 Typical R-values per inch of thickness
o 3.2 U.S. regulation
* 4 See also
* 5 External links
* 6 References

[edit] U-value

The U-value describes how well a building material conducts heat. Methodologically, it measures the heat transfer of a material of known thickness over a given area under standard conditions. The usual standard is at a temperature gradient of 24oC at 50% humidity in no wind conditions.[1]

U is the inverse of R i.e. U = 1/R and the SI unit for U is W/(K·m²).

For example, if the interior of your home is at 20 °C, and the roof cavity is at 10 °C, the temperature difference is 10 K. Assuming a ceiling insulated to R–2, energy will be lost at a rate of 10 K / 2 K·m²/W = 5 watts for every square metre of ceiling.

A lot of you are questioning the insulation in this house, and the R value issues, so let me tell you what I know – the walls are made from fiberglass panels with translucent insulation in between the two panels. We haven’t been told by the architect precisely what the wall panels are – but they look pretty similar to Kalwall Nanogel insulated panels.

http://www.kalwall.com/revolutionary.htm

Even if they aren’t made by Kalwall, they probably use similar technology – and these type of translucent daylit wall panels typically have an R value of 20. We’ve talked about Nanogel/Aerogel translucent insulation before on Inhabitat:

http://www.inhabitat.com/2006/08/10/lets-talk-about-insulation-baby/

The insulation is actually pretty good, so people complaining about lack of insulation should do a bit more research. And it is a steel frame house, so I’m sure it is wind-resistant – much more so than a wood house would be. That said, this is a house that is designed for California, and there is a beauty to that – it suits its climate perfectly. I’m sure it wouldn’t be nearly as successful in Chicago with snow piling up on its roof. Where people are getting the notion that a design has to be universally applicable to all climates in order to be good is ludicrous. There is no “universal” design. This is what vernacular architecture is about – design suited to the particular climate it is located in. I’m sure there are good prefab solutions for Chicago out there, and this is probably not it.

Thanks for reading-
Jill
Editor, Inhabitat