Air-to-refrigerant heat exchangers (HXs) are critical components in Heating, Ventilation, Air-Conditioning, and Refrigeration (HVAC&R) systems. Improving the performance of such devices typically involves reducing the dominant airside thermal resistance using novel fin-and-tube shapes. Recent advancements in high-fidelity simulation tools and advanced manufacturing techniques have led researchers to apply shape and topology optimization to HX design problems, resulting in HX geometries with novel, non-round bare tube shapes which have the potential to outperform existing state-of-the-art HXs. In this paper, we present the retrofit and experimental testing of an 8.4 kW (2.4-Ton) R410A packaged air-conditioning (A/C) unit at AHRI test conditions retrofitted with a conventionally manufactured non-round bare tube evaporator prototype which utilizes shape and topology-optimized bare tubes with an airside hydraulic diameter of ~2-3 mm (0.08-0.12 in). The packaged A/C unit was first experimentally evaluated with its baseline tube-fin HXs installed, then retested after replacing the baseline evaporator with the new HX prototype as a drop-in replacement to determine the impact of this new type of HX on overall system performance. Experimental results show a ~10% reduction in cooling capacity and coefficient of performance (COP), with a 15% and 56% reduction in R410A charge and evaporator core envelope volume, respectively. This was mainly attributed to the evaporator being undersized for the application of interest. A system-level simulation model was built and calibrated using experimental data from baseline unit testing. It was found that that retrofitting the packaged A/C unit with properly-sized HXs can result in a retrofitted system with nearly identical performance to the baseline system with ~50% charge reduction, showing these new HXs can serve as a viable high performance, reduced charge drop-in replacement HX for the present application. The paper concludes by highlighting challenges and future recommendations.