A worldwide shortage of drinkable water has resulted from the rapid rise of industrialization and population, prompting researchers to find an alternative method to fulfil this requirement. Solar still systems are powered by solar energy that can provide drinkable water. However, it has a low production issue. This study investigates the performance of two types of solar stills: a conventional solar still and an advanced solar still. Modifications such as an external condenser, a water heating coil, and nano-phase change material (ZnO-PCM) were employed to enhance the productivity of the advanced solar stills. The results demonstrated that the advanced solar still with a heating coil achieved a thermal efficiency of 46% and a yield improvement of 77%, the advanced solar still with an EC achieved a thermal efficiency of 53% and a yield improvement of 119%, and the advanced solar still with ZnO-PCM achieved a thermal efficiency of 51% and a yield improvement of 113%. The productivity of the advanced solar still was enhanced by approximately 36% with ZnO-PCM and by 42% with an external condenser. Economic analysis revealed the cost of desalinated freshwater to be $0.030 per litre for the conventional solar still, $0.023 per litre for the advanced solar still with ZnO-PCM, and $0.021 per litre for the advanced solar still with an external condenser.