Cost-Effectiveness and Energy Impact of Phase Change Materials (PCMs) in Building Envelopes for Hot-Humid Regions: The Case of the UAE

This study evaluates the technical performance and life-cycle economics of integrating phase change materials (PCMs) into residential building envelopes in the United Arab Emirates (UAE), a hot-humid climate with high cooling demand. Using DesignBuilder (EnergyPlus), a validated two-story base case was modeled, and a factorial analysis was run across envelope components (walls, roof, glazing), PCM placement (interior or exterior), and PCM thicknesses (3 cm and 5 cm) with a paraffin PCM at 47℃, followed by targeted tests at 31℃ and 55℃. Life-Cycle Cost (LCC) and Net Present Value (NPV) analyses were carried out using UAE-specific tariffs and market pricing, and sensitivity tests explored ultra-thin layers and unit-cost reductions. Results indicate that glazing-integrated PCM with a 5 cm layer melting at 55℃ yields the largest reduction in energy utilization intensity (EUI) (≈11% versus the base case). A 3 cm layer delivers nearly the same EUI reduction with ~40% less material, indicating that thickness has a small marginal effect on energy performance but a large effect on cost. Under current prices, payback for the 3 cm, 55℃ case approaches ~30 years; a 1 cm layer cuts payback to ~7 years with only ~1% difference in EUI reduction, and a 50% PCM price reduction (e.g., via local paraffin-based production) can shorten payback to ~4 years. These results offer guidance on where and how PCMs are most effective in UAE housing and identify cost as the primary adoption barrier, suggesting thinner layers and local manufacturing as feasible pathways to financial viability.