Harris theorems are powerful tools for studying the asymptotic behavior of Markovian models. Originating from the probabilistic literature, they were recently adapted to the PDE framework by Hairer-Mattingly and Cañizo-Mischler. I will present some recent works in which this method furnishes an alternative strategy for treating kinetic models with boundary conditions. I will discuss in particular the long-time behavior of the free-transport kinetic equation and of the linear Boltzmann models when the gas is enclosed in a domain with diffuse or Cercignani-Lampis boundary condition and variable temperature at the wall, which, in general, can not be handled with usual hypocoercivity methods. [Seminario congiunto di Probabilità e Fisica Matematica]