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Sustainable design
About EcoDesigner, Energy Evaluation, Life Cycle Assessment, etc.

Ecodesigner - good resource to understand U-values, etc

Haneef Tayob
Booster
Does any have a suggestion for good internet resource to understand U-values for different materials, combining, etc.
My physics 101 course was ages ago and I want to be able to use EcoDesigner to its maximum.
Haneef Tayob
Aziz Tayob Architects
AC23 INT rel 3003, OS X 10.14.6 iMac 3.3ghz i5 dual monitor, 24GB RAM
11 REPLIES 11
Anonymous
Not applicable
Try http://www.diydata.com/information/u_values/u_values.php for some general approximations.

The best source is usually the product manufacturer. Some will even do dew-point calculations gratis.
Anonymous
Not applicable
The U value depends on the material you use, its thickness and on the surface resistance of the air.

You can read about thermal transmittance here: http://en.wikipedia.org/wiki/Thermal_transmittance

About the U value in the link indicated bu Samovar, those elements have rather bad insulation performance.

Generally speaking, you want the lowest U value as possible (according to your budget).

For example, the best performing exterior wall listed in that page has a U value of 0,6 W/m2K. Here in Italy, it is not legal to build anything with such a low performance (current maximum allowed U value in my area is 0,24 for the vertical opaque envelope).

For passive design, the maximum U value is 0,15 for walls and roofs, and 0,80 for windows (Uw).

If you tell me more about what you need these values for, I may be able to help you more.
Anonymous
Not applicable
the Energy Saving Trust in the UK has some excellent scientifically researched advice.

Here's a link to their chart of different insulation types used in construction:

http://www.energysavingtrust.org.uk/Publications2/Housing-professionals/Insulation-and-ventilation/Insulation-materials-chart-thermal-properties-and-environmental-ratings
Anonymous
Not applicable
The chart published at the link above can be a starting point. However, if you want to get started on actual energy efficient design, those values are too general for any practical use in design.
Anonymous
Not applicable
Hi All

Just bought Ecodesigner and try to set it up. Can someone explain ho to set external/internal heat coefficient?

Thanks
Tom
Anonymous
Not applicable
you can find basic info about the R-value and U-value calculation on Wikipedia:
http://en.wikipedia.org/wiki/U-value#U-value

The internal/external heat transfer coefficients are two standard values (measured in lab, and their values are fixed and standardized) that show the contribution given by the internal/external air to the overall insulation value of your structure. These values depend on the geometry of your structure (whether it is a horizontal slab or a vertical wall, for example), and on the ventilation ratio of your external conditions.

Basically, the very first layer of air next to the surface of your wall/slab stays still, and helps insulating the structure.

For example, the standard R-values for a vertical structure are:

Internal: 0,13 Km2/W;

External: 0,04 Km2/W.

You can find other standard values in the wiki article above.
Anonymous
Not applicable
Thanks for big help it explain a lot but will comeback with questions if you don't mind?

Best Regards
Tom
Anonymous
Not applicable
I don't mind at all, I may just take sometime to answer.
Anonymous
Not applicable
I found and printed manual then I think I will be fine with basics but maybe anyone has sorted typical skims like for UK:

blockwork (100 or 140mm), cavity: wool insulation 90mm + 10mm void, brick or stone work 100mm

or for Central Europe:
autoclave blocks (24mm), EPS insulation (150mm)

or anywhere:
timber stud (140mm) with wool insulation in between + extra 50mm of foam
between counter battens

I have no problem with U value for them, found some on-line calculators but how to sort rest of parameters for them in Ecodesigner?

Maybe someone could send any open Archicad files to have a look I promise to send mines to anyone when done
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