Derives an analytical theory for the calculation of the angle factor and effective radiation area of the human body and offers the radiation data by means of measurement using the orthographic projection camera. Gives values for the effective radiation factors determined for a sedentary nude, sedentary clothed, standing nude and standing clothed person. Provides diagrams of angle factors between the human body and rectangular planes. Finds the angle factor between the human body and floor deviates from Fanger's factor by more than 40% in some instances. Concludes that since the human body is considered a finite-size object in contrast with Fanger's human element, the angle factors are more suitable for estimation of man's radiant heat exchange in floor heating systems and in relatively small rooms.

KEYWORDS: Heat flow, angle, comparing, comfort, measuring, floor heating, radiant heating.