This study investigated the feasibility of reducing energy demand in residential buildings using a new material called “Phase Change Material with Mycelium Integration (PCMMI)”, considering the climatic conditions in Jordan, Amman. Feasibility study in this research was evaluating the materials cost (with and without PCMMI) versus the return on the energy savings. All costs calculations where in Jordanian Dinars (JD). Parametric analysis of a room in the simulated residential building was studied (using Autodesk-Dynamo program) to compare materials’ cost and energy savings throughout the year (techno-economic feasibility study). The results of the techno-economic feasibility study showed that by adding a layer of PCMMI (costs JD 7/m2), the room materials’ cost increased by JD 469, but it would reduce JD 600 of the annual energy consumption cost as compared to building materials currently used.