Low-carbon building materials, such as earth- and bio-based ones, have an excellent capacity to regulate indoor moisture levels. Thanks to their hygroscopic nature, they can buffer moisture from the indoor environment, absorbing it when humidity increases and releasing it when the air becomes drier. This moisture-buffering capacity can significantly improve indoor comfort and well-being. However, the extent of this benefit depends on factors like building usage, occupancy, ventilation rates, and external climate conditions. Thus, dynamic numerical simulations are often necessary to quantify the materials’ benefits considering specific building scenarios. This paper investigates incorporating moisture dynamics evaluation into early architectural design workflows using the Grasshopper interface of Rhinoceros. This integration offers an advancement beyond conventional building performance simulations provided by current Grasshopper plugins. The paper explores the effectiveness of the newly developed WaterSkater plugin in assessing the hygrometric benefits of using moisture-buffering materials in architecture. This study represents the first application of the plugin, with future studies planned to validate its accuracy and correctness. The plugin discussed in this study allows for integrating materials’ moisture buffering capacity into early-stage architectural design workflows. This step enables designers to strategically select materials that align not only with sustainability objectives and desired U-values but also understand their potential for indoor humidity regulation. The presented plugin enables the incorporation of low-carbon, moisture-buffering materials from the early stages of building design, allowing for a strategic use of their moisture-regulating potential to improve indoor comfort and reduce the need for ventilation and humidity-control mechanical systems.