Towel warmers  can be installed on almost any type of surface without any issues. The towel warmer is there to dry the towel out, but it will also help dry out the air in the bathroom to help reduce humidity and thus moisture/mold/mildew. More than 50% of  towel warmers are installed onto drywall surfaces, as that is the most common wall surface used in the states. It could also be installed onto tile without problems, as well as bead board.