Problem is, most racks have heat tape to provide a hot spot for the snakes of around 87-90f, but the snakes need to have the ability to escape that heat when they aren't digesting or resting. If you kept a snake room at those temps the snakes would overheat and die of stress eventually. You keep the room lower than that with no hot spot and the snakes won't digest food properly and will again die. So you really do need a range of temps for the snakes to have access to for them to function properly.
Room temp would need to be adjusted based on the power of your heat source.