This study based on the preparation and characterization of PEG/cellulose, PEG/agarose, and PEG/chitosan blends as form/stable phase change materials (PCMs) for latent heat energy storage. 60/40% w/w PEG/cellulose, 70/30% w/w PEG/agarose, and 80/20% w/w PEG/chitosan blends were found to contain maximum PEG without leakage above melting point and are characterized using Fourier transform infrared (FT-IR) spectroscopy, polarized optic microscopy (POM), and differential scanning calorimetry (DSC) techniques. DSC analysis indicated that the form-stable PEG/cellulose, PEG/agarose, and PEG/chitosan blends melt at 58.51°C, 57.73°C, and 57.18°C with 84.63J/g, 110.87J/g, and 152.16J/g latent heats, respectively, as they crystallizes at 37.05°C, 43.36°C, and 44.76°C with −78.92J/g, −99.01J/g, and −138.39J/g, respectively. Accelerated thermal cycling tests were applied to present thermal reliability and chemical stability of the shape stabilized blends.