  Describing the emergence of phases of condensed matter is one of the central
challenges in physics. For this purpose many numerical and analytical methods
have been developed, each with their own strengths and limitations. The
functional renormalization group is one of these methods bridging between
efficiency and accuracy. In this paper we derive a new truncated unity (TU)
approach unifying real- and momentum space TU, called TU$^2$FRG. This formalism
significantly improves the scaling compared to conventional momentum (TU)FRG
when applied to large unit-cell models and models where the translational
symmetry is broken.
