heat vs infrared (it eludes me)

With heat being the transfer of thermal energy, I simply imagined it as "wiggling" molecules "bumping" into the wiggling molecules of the other substance, until all the energy reaches an equilibrium. I'm not entirely sure how infrared waves factor into this though. (I was under the impression that waves were simply energy, but I realize now that they simply have energy. Although, if energy is simply "the potential to transfer work/motion," then what are waves in actuality? If energy is less of a tangible property of the universe and more so functions to assist with numerical calculations, what does that make waves? ... I don't understand electromagnetism at all with this; I would like explanations) 

About infrared waves specifically though (since that plays a role in climate change if I remember correctly), do those transfer heat? If so, is it because they cause electrons to become excited, meaning that the repulsion-based "bumping" of the atoms increases? (Do excited states change the overall movement/energy of the molecule/or atom itself though?)