[EN] This bachelor thesis will explain how it is possible and which factors are important to obtain buildings which apply for certificates such as passive or active buildings. These buildings belong to a group of buildings called nearly zero energy buildings. This will be done for Spain and Belgium. The main influences such as the climate differences will be explained because they have a significant influence on the building performances. At the end, the way we calculate the energy performances of buildings will be explaine. ; [ES] Esta tesis de licenciatura explicará cómo es posible y qué factores son importantes para obtener edificios que soliciten certificados como edificios pasivos o activos. Estos edificios pertenecen a un grupo de edificios llamados edificios de energía casi nula. Esto se hará para España y Bélgica. Las principales influencias tales como las diferencias climáticas se explicarán ya que tienen una influencia significativa en las actuaciones del edificio. Al final, se explicará la forma en que calculamos el rendimiento energético de los edificios ; De Sloovere, MKD. (2019). Comparison between Spain and Belgium in the field of energy performance and passive buildings regulations. http://hdl.handle.net/10251/124355 ; TFGM