Despite the fact that different research works have developed building simulation tools, employing actual sampled data to validate them is required. In previous research works [1], the effect of permeable covering in a humid region of Spain was shown based on real sampled data and statistical studies. The main results showed a clear improvement of indoor ambiences of buildings with permeable internal coverings, like wood and plaster, in contrast with the other ambiences under impermeable internal coverings, like paint and plastic [2,3]. This same effect could be related, at the same time, with an average and immediate improvement in local thermal comfort [4–9] and energy saving [10]. Results show how permeable coverings allow construction materials in building walls to absorb very high humidity in the indoor air and release it when the humidity is very low. This effect showed a clear working behaviour during the unoccupied hours of the office buildings. During this period, the number of air exchanges is reduced, and the infiltrations by doors and windows are nearly null. Consequently, indoor ambience during the first hour of occupation was modified towards favourable conditions, thus reducing peak energy consumption during that period.