The applicability of more than 70 semi‐crystalline polymer grades with different melting temperatures as phase change materials (PCM) is investigated. Their storage capacity (heat of fusion) and application temperature range (defined by the melting temperature range and the degradation behavior) are analyzed via differential scanning calorimetry (DSC). Application‐oriented stability investigations (thermal cycling and exposure to static thermal load above the polymer’s melting temperature) are applied on the most promising polymer types. The thermal and thermo‐oxidative degradation behavior is monitored via DSC and Fourier‐transform infrared spectroscopy. Different aging phenomena are identified. However, these have only little impact on the polymer’s storage capacity. Therefore, a great potential of polymers as PCM is revealed. Additionally, the economic efficiency of polymers as PCM is estimated and discussed.