"Jim Wilkins" fired this volley in
:

Trouble is, they don't radiate infrared and the heated air from the
ballast stays near the ceiling.

Not _quite_ true.

It's true that most of the heat stays near the ceiling, because most of
it is conducted away from the housing by convection. However... (It's
SCIENCE!) ALL objects warmer than their surrounds also radiate in the
infrared. (Hint... infrared IS "heat". Radiation is one of the three
ways heat moves)

G
LLoyd