One-dimensional solutions to Fourier's equation and measures of heat transmission through walls: The role of wall decay times

The four forms of solution to the one-dimensional equation for heat transfer are presented and their bearing on the derivation of various measures of heat flow in building walls, including response factors, is reviewed. One of the series leads directly to a series of wall decay times. A study based on Fourier series is reported to demonstrate that, contrary to general belief, wall decay times are not needed to evaluate the wall response factors.