The rate of heat loss Q . loss through a window or wall is a function of the temperature difference between inside and outside ? T, the window surface area A, and the R value of the window, which has units of (ft2 . h . °F)/ Btu. (a) Using the Buckingham Pi Theorem, find an expression for rate of heat loss as a function of the other three parameters in the problem. (b) If the temperature difference ? T doubles, by what factor does the rate of heat loss increase?