Aluminium entrance doors have numerous advantages over plastic ones, the main ones being their longer service life and better insulation. Due to its better static stability and greater strength, aluminium is better at withstanding extreme temperatures, so it is much less susceptible to bending.
This is crucial given the temperature differences between the outside and the inside, which occur in both summer and winter. Bent door leaves fit more poorly into the door frame and consequently result in poorer sealing, which results in heat loss and thus higher heating costs. Such doors must also be replaced earlier.
You can read more about why Inotherm entrance doors can withstand all types of weather so well in the article.