A closed analytical expression for calculating the TEMA H-shell F factor ( mean temperature difference correction factor) is derived. The F factor, computed for various values of the number of transfer units ( NTU) and the heat capacity rate ratio ( R) are found to be almost identical to values of the TEMA G-shell F factor over most of the parameter ranges. The difference becomes significant only when NTU is greater than 20 and R is greater than 4. Therefore, this work confirms that, for all practical purposes, the G shell F factor can be substituted for the H-shell F factor. This derivation completes the set of analytical expressions for F factors of all the TEMA shell types