The gain of thermal infrared instruments in the 2–25 μm wavelength range from Antarctica is summarized by comparing three parameters: the ambient temperature; the atmospheric transparency, with perceptible water vapor content (PWV) in particular; and the image quality. For the 2 m class infrared telescope projects at Dome C the estimated mid infrared point source sensitivity can be compared to the sensitivities reached at 10 m class telescopes elsewhere. This comparison favors a thermal IR instrument at Dome C with focus on key science cases; two examples are: i) Survey type projects, such as mid infrared photometric imaging or spectro–polarization campaigns of YSO. Or ii) monitoring and rapid response observations on the Galactic Centre, the LMC, SN or GRB.