ΔE 29.1, loose: different enough that you should pick on purpose. Sunset Red is a little darker, more muted, cooler than Demon Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Sunset Red is a little darker, more muted, cooler than Demon Red.
The same difference applies the other way round: Demon Red is a little lighter, more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Demon Red on the colour wheel See Sunset Red on the colour wheel
All matches: Demon Red equivalents · Sunset Red equivalents