Polar codes are simple codes, which are based on the polarization effect of the polarisation matrix and they are the first to achieve Shannon's channel capacity for binary discrete memoryless channels. The straightforward encoding and decoding processes of polar codes makes it suitable for the fifth generation (5G) new radio, which requires higher efficiency and better reliability along with low cost. In this work, the reliability and energy efficiency of polar codes are documented through extensive Monte Carlo simulations over Rayleigh flat fading channel. © 2020 IEEE.