Radiative cooling and heating rates against radial distance for the CHAIN runs of the H₂O atmospheres of planets b (top panel), c (middle panel), and d (bottom panel). The rates are shown between 1 and 4 R_pl, where most of the photochemistry takes place; higher altitudes are dominated by adiabatic expansion. For individual cooling processes, we only show those that contribute at least 5% to the total cooling rates (at some specific altitude). The line styles are explained in the legends, where the notation is the following: C_tot – total cooling rate (the sum of all radiative processes); H_tot – total heating rate; μbar – the altitude corresponding to 1 μbar pressure level; X line – line cooling of the X element; molecule – the sum of molecule cooling processes (dominated by H₂O molecule cooling); free-free H – bremsstrahlung cooling from hydrogen and helium.