Ionised fraction of hydrogen. Extrapolation of the predictions (at z ∼ 15 − 30) from our CHE and standard models are shown with thick solid and dashed curves. For comparison, we plot the results from the semi-analytical models ASLOTH (Hartwig et al. 2022), 21cmFAST (Muñoz et al. 2022) and Astraeus (Hutter et al. 2021), as well as cosmological simulations ASTRID (Bird et al. 2022), THESAN (Kannan et al. 2022) and SPHINX (Rosdahl et al. 2018) with thin solid and dashed curves, respectively. The vertical lines show the redshift range (z ∼ 5.5 − 15) in which our predictions at high-z are extrapolated to the post-reionisation epoch.