The following summary of how steam-heat residential radiators work appeared on
another list. Is this correct thinking?

1.  The majority of heat tranfer on radiators results from _convection_
(natural convection), not radiation.  I think it's around 70%-80%
convection & only 20-30% radiation.  The temperature delta between
the radiator and the surrounding is not large enough for radiation
to dominate.  So, they really oughta be called "convectors"!
BTW - Convection refers to heat txfer from the _flow_ of a fluid
(air in this case).  By "natural" convection, I mean that there's
no fan or blower.  Air naturally circulates in the room through
the radiator.

John Leeke, Preservation Consultant