Max Demian wrote:
On 05/10/2020 18:49, williamwright wrote:
On 05/10/2020 12:28, JohnP wrote:

A black radiator gives off more heat.

Why should the efficiency of a surface in absorbing light affect its
efficiency in radiating heat?

Because a guy called Kirchhoff said so.


As I recall, irrespective of the finish, due to the surface temp over 75%
of the heat transfer to the room from a domestic radiator is via
convection.