insulation, performance, efficiency, R-Value, energy transfer
Back in 1945, Everett Shuman promoted R-value as a standardized way to measure a material’s resistance to heat transfer. But R-values can only be achieved in laboratory conditions where there is no wind, no moisture and no framing members. Of the three forms of energy transfer (conduction, convection and radiation), there is more heat transferred through radiation than through conduction and convection combined. In the summer 93% of heat gain is caused by radiant energy and in the winter between 50% – 75% of heat loss is due to radiant energy. Currently, there is no standard test to measure these real world conditions. So we must use other tools to see how insulation performs.