Energy generation affects directly global warming. As buildings consume a large portion of the total generated energy, it is crucial to keep the energy consumption of this sector as less as possible. Poor insulation is the main source of energy losses from buildings envelopes. Although many countries have their rules now to control buildings insulation for new buildings, existing buildings still require a practical tool to check their insulation. In this work, a new approach named Building Insulation Analyzer is developed and coded (BIA Software) to measure the differences between the inside and the outside temperatures at each point from the building façade. It has been found that three points using the first degree polynomial equation are optimum for the registration. A stable behavior is shown in the validation process. The temperature differences for the studied façade were ranged from two degrees at the openings to five degrees at the isolated and thick walls.