This paper proposes an energy efficient millimeter wave (mmW ave) hybrid multiple-input multiple-output (MIMO) beamformer with low resolution digital to analog converters (DACs) at the transmitter . W e consider the case where all DACs have the same sampling resolution for each radio frequency (RF) chain and select the best subset of the active RF chains and the DAC resolution. A novel technique based on the Dinkelbach method and subset selection optimization is proposed to maximize the energy efficiency (EE) given a predefined power budget for transmission. W e also implement an exhaustive search approach to serve as an upper bound on the EE performance and show the performance trade-offs. The simulation results verify that the proposed technique exhibits EE performance similar to the optimal exhaustive search technique while requiring lower computational complexity . Index T erms—energy efficiency maximization, low resolution DACs, mmW ave MIMO, hybrid beamforming. I. I N T RO D U C T I O N Millimeter W ave (mmW ave) technology can meet the needs of the fifth generation (5G) wireless communication systems and provide improved rate and capacity [1], [2].