During the evolution of a classical nova outburst, there are four times at which a significant infra-red (IR) flux is expected. The first Isothermal Dust Phase has been observed in a number of novae and analyses of this phase give valuable information on the properties of the emitting dust. In order of time from visual maximum, the three later phases are due to IR emission from X-ray heated grains, fine-structure line emission from a cold phase of the nova nebula, and grain cooling from shocked gas at the interface between the nova ejecta and the interstellar medium. In the next sections, theoretical estimates of the peak IR luminosity, flux distribution and time of peak emission for each of these phases are discussed.