  We study a $\phi^4$-theory at finite temperature in a finite volume. Quantum,
thermal and volume fluctuations are treated with the functional renormalisation
group. Specifically, we focus on the interplay of temperature and length scales
driving the system. We find that thermodynamical observables at finite volume
such as the pressure approach the infinite volume limit similarly to that of
the vanishing temperature limit. We also advance the functional renormalisation
group method at finite volume. In particular, we identify requirements for
suitable regulators that admit the exponential thermal and finite volume decay
properties.
