The average temperature of all the surfaces in a room being heated by a Radiant Heat System. These temperatures will be relatively consistent in a Radiant Heat System, however in a forced hot air, or baseboard system the temperatures will vary substantially. This thermal comfort is one of the key benefits of Radiant Heat.

The uniform surface temperature of a radiantly black enclosure in which an occupant would exchange the same amount of radiant heat as in the actual nonuniform space.

The average temperature of all the surfaces to which a person is exposed, exchanging infrared radiation.