So this isn't a homework problem persay, it was given information but I just couldn't wrap my head on why this was true. We have 1-d heat transfer through a planar slab. If we have a T_a for the temperature outside, then as we T_1 for the temperature on one end of the surface, and T_2 for the temperature on the other end, and T_b as the temperature outside the building on the other, how can we tell that this is a steady state problem? h is the material thermal convection constant and k is the material thermal conductivity We eventually set the convection flux equal to the conduction flux: J_conduction = J_convection = h(T_h - T_1) = (K/L)(T_1 -T_3) Why is he able to set the fluxes equal to each other? Why wouldn't the convection flux be different from the conduction flux? Perhaps this would be more clear if someone could use an analogy approach of electrical circuits?