The heat of formation of the fire suppressant, 2-H Heptafluoropropane, which is a replacement for ozone depleting halons, AH(f.298) (K)(CF3CHFCF3) has been calculated at the B3LYP, MP2 and CCSD(T) levels with basis sets of up to cc-pVQZ quality, and with the model chemistry methods: G2(MP2), G2, G3 and CBS-Q, employing three reaction schemes. The CBS limit value of -370.6 +/- 2.3 kcal/mol obtained is believed to be the most reliable value currently available. This is recommended to be used in thermochemical/kinetic modelling of the inhibition chemistry of CF3CHFCF3 in flames. (C) 2004 Elsevier B.V. All rights reserved.