Solar domestic hot water (SDHW) can be used to reduce energy bills and greenhouse gas emissions associated with heating domestic water. However, one of the most significant barriers to further deployment of solar thermal applications is the space and weight required for storage of the energy collected. Phase change materials (PCMs) are advantageous for daily energy storage with SDHW due to their high storage density and isothermal operation during phase transitions, and would overcome these obstacles. The aim of this paper is to outline the initial steps in the development of a SDHW energy storage system using PCMs, with emphasis on the numerical and experimental studies used to access the phase change and thermal behaviour of the selected PCM. Lauric acid was selected as the PCM based on the melting temperature range which was targeted by studying solar data from an existing solar hot water system in Halifax, Nova Scotia, Canada. Due to the low thermal conductivity of PCMs, additional work is required to develop and validate a design to enhance heat transfer to the storage material using fins. The selected design will be built and installed in an existing large scale solar thermal system on an apartment building in Halifax. The system will be instrumented in order to acquire continuous data (temperatures, flow rates, pressures, etc.) to fully characterize the system.