The response of mid-latitude equilibrated eddies’ length scale to static stability has long been questioned but not investigated in well-controlled experiments with unchanged mean zonal wind and meridional temperature gradient. With iterative use of the linear response function of an idealized dry atmosphere, we obtain a time-invariant and zonally-uniform forcing to decrease the near-surface temperature by over 2 K while keeping the change in zonal wind negligible (within 0.2 m/s). In such experiments of increased static stability, energy-containing zonal scale decreases by 3-4%, which matches with Rhines scale decrease near the jet core. Changes in Rossby radius (+2%), maximum baroclinic growth scale (-1%) and Kuo scale (0%) fail to match this change in zonal scale. These findings and well-controlled experiments help with better understanding of eddy-mean flow interactions and hence the mid-latitude circulation and its response to climate change.