Electron heat flux as a function of heliocentric distance and solar wind speed. Top panels: net heat flux magnitudes, and bottom panels: normalized net heat flux magnitudes, for the first and second (left panels) and the fourth and fifth (right panels) PSP orbits. The solid lines and diamonds show median values in five solar wind speed bins (each 100 km s⁻¹ in width), and the corresponding dashed lines show the upper and lower quartiles.