New energy provisions in the National Building Code that will be effective in the British Columbia Building Code in December begin to require the performance of building enclosure assemblies to achieve effective R-Values, opposed to nominal values prescribed historically.  Effective R-Values are a far more accurate evaluation of these assemblies, and this shift in the code is a slow but steady step in the right direction of achieving more energy efficient buildings.  However, to determine effective R-Values, some calculation is required.  In response, the Canadian Wood Council has developed a free online tool to look up the effective R-Values of many common wall assemblies we see in residential construction.  There is also the ability to simulate custom wall assemblies to determine the necessary values.  Here is a link to the CWC Wall Thermal Design Tool.  Enjoy!