Home efficiency show

Just looking through a really good write-up on the show last week in BD architects review of the BRE Offsite - as below. There are also some presentations available from BRE which look interesting - you need to sign in with an email address.

Whilst reading the BD article, I found myself looking up the following:

• The UK/British governments "code for sustainable homes" referred to in the article (wonder if there is a North American version of this). Seems to be quite a bit of info (for a change with government docs - why would you use a table instead of random progressive number series)... level 6 is essentially carbon neutral... Date 2010, 25% carbon reduction - level3; 2013, 40% carbon reduction - level4; 2016 - carbon neutral - level6. Energy/carbon improvement as compared to Part L (Building Regulations 2006).
• U-value - from a diypage, wikipedia - "Simply put, it is the number of watts that will be lost per square metre, at a given temperature difference in kelvin. For a simple example, if the interior of your home is at 20 °C, and the roof cavity is at 10 °C, that gives a temperature difference of 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." or 0.5 U in this case.... So the examples for these houses of 0.15W per sq m looks pretty good.
• Heat exchange - stack effect
  
• solar gain
• passive ventilation
  
• Du Pont’s innovative Energain phase change panel
• rainwater harvesting and greywater recycling