As climate change induced severe weather shocks become more frequent, novel approaches that increase the liveability of our existing building stock are critical. Phase change materials (PCMs) are a thermal storage option that, when integrated into buildings, can store solar energy during peak periods and release it during cooler periods. Through this process, PCMs can reduce surface temperatures within a space, reduce air temperatures, improve occupant thermal comfort, and reduce cooling loads. PCMs can be impregnated into wall coatings as an owner-actionable solution to increase the thermal storage capacity of walls around the PCM’s melting temperature. The objective of this study was to develop an experimental apparatus and procedure to compare a variety of coatings impregnated with varying concentrations of PCM. A chamber with a window was built as a scaled down model of a room with a large glazing area. The wall opposite the window was designed such that coated drywall samples could be installed for testing. A solar simulator was built as a source of radiation for the chamber. A testing procedure was developed to evaluate the chamber’s thermal response to the PCM wall coatings. The chamber is heated by the solar simulator for a fixed duration starting below and finishing above the PCM’s melting temperature. Metrics including surface and air temperature rise are then compared between coatings. Comparing these metrics helps predict which coatings may have the greatest potential to achieve energy savings and thermal comfort improvements for future full scale in-situ installations.