The concept of solar heat pin factor has been introduced for calculati
ng the net energy gain of passive heating elements and other component
s of a building as a result of incident solar radiation. For passive h
eating concepts (namely, the direct gain, mass wall, water wall, Tromb
e wall, and solarium), exact analytical expressions have been obtained
for the solar heat gain factors and the corresponding overall heat lo
ss coefficients. These will allow a building designer to calculate imm
ediately the overall heat gain/loss in a building. Numerical calculati
ons have been done for typical values of solar radiation and ambient t
emperature of typical climatic conditions in India. The method has bee
n compared with the other methods reported in the literature so far. A
good comparison is found between the earlier methods and the method o
f using solar gain factors and the corresponding heat transfer values.