  It is well known that thermal insulation is a leading strategy for reducing
energy consumption associated to heating or cooling processes in buildings.
Nevertheless, building insulation can generate high expenditures so that the
selection of an optimum insulation thickness requires a detailed energy
simulation as well as an economic analysis. In this way, the present study
proposes an innovative non-uniform adaptive method to determine the optimal
insulation thickness of external walls. First, the method is compared with a
reference solution to properly understand the features of the method, which can
provide high accuracy with less spatial nodes. Then, the adaptive method is
used to simulate the transient heat conduction through the building envelope of
buildings located in Brazil, where there is a large potential of energy
reduction. Simulations have been efficiently carried out for different wall and
roof configurations, showing that the innovative method efficiently provides a
gain of 25% on the computer run time.
