Thermal performance and wall ratings

This paper proposes for consideration as a nationally accepted consensus methodology a procedure for estimating the whole opaque wall R-value (whole-wall R-value), independent of system type and construction materials. The methodology is based on results from a three-dimensional heat conduction model capable of simulating heat flow in a variety of wood, metal, and masonry systems. These simulation results lead to a whole-wall R-value which include the thermal performance of not only the clear wall area, with insulation and structural elements, but also typical envelope interface details, including wall/wall (corners), wall/roof, wall/floor, wall/door, and wall/window connections. Results from these detailed computer simulations are combined into a single whole-wall R-value estimation and compared with simplified center-of-cavity and clear wall R-values.