This study conducts a comparative techno-economic assessment of three heating systems: a conventional heat pump (HP), a water-based sensible heat storage integrated heat pump (WSHP), and a phase change material-based latent heat storage integrated heat pump (PCMHP). The analysis evaluates the systems’ performance in a 100 m2 commercial building over a 10-year period. Results indicate that WSHP significantly reduces initial investment costs compared to conventional HP, while PCMHP, despite higher initial costs, offers lower operational costs and potential long-term economic benefits. The study highlights the importance of balancing energy efficiency and system costs, suggesting that WSHP is more cost-effective for short-term use, whereas PCMHP may be more advantageous over extended periods. The findings underscore the role of thermal energy storage in enhancing heat pump efficiency and reducing carbon emissions.