  We consider a variational approach to the finite temperature Yang-Mills
theory in the Coulomb gauge. The partition function is computed in the ensemble
of glueballs and quasi-gluons which emerge as eigenstates of the Coulomb gauge
Hamiltonian. We compute the energy density and pressure and compare with
results of lattice computations for both SU(2) and SU(3). The emergence of a
phase transition is discussed.
