Recent research has emphasized the benefits of adaptively regulating the sampling rate of a plant as a function of its state of operation. In this letter, we study the problem in the context of the wide variety of low power embedded systems, where sampling rate has a direct relationship with power consumption. We propose a methodology for designing multirate controllers that switch between sampling rates depending on the disturbance levels while operating under a given energy budget. Our empirical studies indicate that better control performance can be achieved within the energy budget by adaptive regulation of the sampling rate, thereby demonstrating the efficacy of our proposal.