U-values provide a measure of heat loss for all elements of the build to include the complete wall, roof and floor construction. These figures are measured in w/m2k which signifies the amount of heat loss in watts (W) per square metre of each element of the build while the outside temperature (K) is at least 1 degree lower than the inside of the building.
The lower the u-value, the better the insulating property of that particular element. However, not each element has its own u-value. It takes a combination of all elements contributing to the structure in order to deliver a combined u-value for your overall build.
For example, assuming a 100mm external leaf of blockwork, our insulation packages using quality insulation, air tightness membrane and tapes achieve u-values as low as 0.09 where passive standard ranges from 0.11 to 0.15 w/m2k. It is important to note that u-values are just one component of a build envelope. Air tightness and minimal thermal bridging are equally as important to achieving reduced heating bills and a comfortable home – both of which timber frame quickly and cheaply overcomes.