Annual fees must also be paid for the unitary patent in order to maintain it after the application has been filed. Instead of paying various renewal fees to the respective national patent offices, as is the case with the classic European patent, only a single renewal fee has to be paid to the European Patent Office for the extension of patent protection in all member states.
It is not possible to give a general answer as to whether the unitary patent will mean cost savings for applicants. It depends on in how many countries the classic EP patent would otherwise be validated:
The illustration on the website of the European Patent Office shows that the unitary patent is significantly cheaper if an EP patent would otherwise be validated in 25 countries. However, if one compares the costs of the unitary patent with the validation and maintenance of a classical EP patent in only four countries, the saving for the unitary patent is only a few percent.
So, purely from a cost perspective, the unitary patent only makes sense if a classical EP patent would otherwise be validated in at least four countries. However, the potential saving is certainly not the only advantage of a unitary patent.