The gain of thermal infrared instruments in the 2–25 μm wavelengthrange from Antarctica is summarized by comparing three parameters: theambient temperature; the atmospheric transparency, with perceptiblewater vapor content (PWV) in particular; and the image quality. Forthe 2 m class infrared telescope projects at Dome C the estimated midinfrared point source sensitivity can be compared to the sensitivitiesreached at 10 m class telescopes elsewhere. This comparison favors athermal IR instrument at Dome C with focus on key science cases; twoexamples are: i) Survey type projects, such as mid infraredphotometric imaging or spectro–polarization campaigns of YSO. Or ii)monitoring and rapid response observations on the Galactic Centre, theLMC, SN or GRB.