U-values

Slig

I have being researching passive house design over the last 2 days (have to look busy even though there is nothing else to do) and I have been seeing a lot of "scandinavian U-value of 0.2" and "Dutch U-value of 0.1"
(I have also picked up alot of other questionables like most of your heat escapes through the floor but thats for another day)

Is there no standard U-value calculation? or are these just calculated with a different Rsi & Rso and worded to sound better?

sas

I am more adding to this than providing answers.

This is something I've been meaning to ask for a while. On this site http://www.scanhome.ie/passive.php under the section titled "UPGRADING THE STANDARD SCANDINAVIAN HOMES LTD HOUSE TO A PASSIVE HOUSE:" there is a "Wall" build=up description.

They make reference to a swedish u-value calc method. and a british method.

So again, can anyone shed any light on this.

If someone feels like trying to work out if we use the british or swedish method, I'm fairly sure that the thermal conductivity of the mineral wool used by scanhome is 0.037. FWIW, my playing on the SEI u-value calc suggests we use the swedish method.

Disclaimer: I neither work for nor have ever purchased from ScanHome. The mods have allowed me to name them for the purposes of this discussion.

sinnerboy

Here and in UK , this is how it is done

http://www.bre.co.uk/filelibrary/rpts/uvalue/BR_443_(2006_Edition).pdf

these 2 software packages are based on this code

http://www.xtratherm.com/software/software.php

http://www.builddesk.co.uk/our+software/builddesk+u/download