This letter proposes an energy detection scheme based on short windows to detect the presence of a burst signal that spans over a short period of time. For practical use, the proposed scheme provides a simple computational method for the threshold, with which the measured energy is compared, that satisfies a target false alarm probability and also the optimal length of the short window that minimizes miss detection probability. To evaluate the performance of the proposed scheme, miss detection probability is analyzed as a function of the threshold. Simulation results demonstrate that the proposed scheme provides a lower miss detection probability than the conventional scheme when a burst signal is present.