Don Foreman writes:

Declaring him ignorant is
neither helpful nor defensible by technical premise you present.

Indeed it was the wrong term, I apologize.

A 25% efficient 5 HP lawnmower engine
dissipates more heat than that, with far less surface area.

Perhaps, but it has the advantage of blowing most of that heat out the
exhaust, instead of raising itself to a temperature that blackbody radiates
it.