Known ZZ Ceti stars (red filled dots, atmospheric parameters from Bognár & Sódor 2016), and DAVs observed by TESS during the survey measurements of the southern ecliptic hemisphere (sectors 1–13) in the T_eff − log g diagram. Black and green dots mark the stars found to be variable and not seen to vary by the TESS measurements, respectively. Their atmospheric parameters were derived by Fuchs (2017), except in the case of KUV 03442+0719, where we used the values presented in Bognár & Sódor (2016). Blue and red lines denote the hot and cool boundaries of the instability strip, according to Tremblay et al. (2015).