Tube-bundle heat exchangers are widely utilized in gas-togas and gas-to-liquid applications, and interest remains high in improving the efficiency of these heat exchangers. Due to excellent resistance to fouling and corrosion, polymer heat exchangers have been mainly applied under extreme working conditions, where such concerns are important. Recently, however, there has been interest in using polymer heat exchangers as a substitute for conventional metallic heat exchangers in more general applications. The present study explores the optimization of bare polymer tube-bundle (PTB) heat exchangers and determines the cost effectiveness of PTB heat exchangers through comparisons to conventional metallic heat exchangers using a Genetic Algorithm (GA). Most of heat exchanger optimization studies have focused mainly on the physics of the fluid flow or heat transfer enhancement, and a detailed analysis including geometry and cost is rare. The present study is distinguished from others by focusing on objective functions involving cost under volume constraints and undertaking geometry optimization with sensitivity analysis.