A numerical investigation has been carried out to determine the effects of condensation inundation, noncondensable gases, and cooling water velocity upon the local and overall condensation heat transfer in horizontal tube bundles. Five inundation correction factors are tested against the experimental data. Comparisons between the predicted results and the experimental data are made in terms of total condensation rates and local heat flux distributions. The effects of noncondensable gases and cooling water velocity arc assessed by comparing local heat flux distributions, total condensation rates, and average steam-side and average overall heat transfer coefficients under different inlet air mass fraction and inlet cooling water velocity conditions.