How your data might look and how to extract : heating cooling temp. (C) 40 .30 20 50 100 time (1 150 T(t)=T +(T-T )e 0=e where 200 = T: platetemp T: ambient temp. T-T To-Too te pvc .. In0=-=-t/t ; apply linear fit to find slope -1/t (and then and Bi) t hA and T=- -t