The processing power of handheld electronic devices has increased rapidly over the last decade. Modern handheld devices are thin (<9 mm) and utilize passive temperature control strategies. The combination of these factors has resulted in temperature control becoming a major obstacle to continued development. This work investigates the use of latent heat storage modules to improve the temperature control of tablet computers. Such modules store energy during periods of high heat dissipation and release it later when the device is less active. A key design aspect for these systems is identification of the appropriate phase change materials (PCMs), and specifically the optimal transition temperature. A numerical model of a tablet computer was created. Simulations with latent heat storage modules with transition temperatures between 35 and 47 °C showed that PCMs with lower transition temperatures allowed the tablet computer to operate longer without overheating. PCMs with transition temperatures between 35 and 40 °C were found to be most suitable.