This paper uses an Instruction Set Architecture(ISA) based statistical energy model of an ARM Cortex-M4microprocessor to evaluate the energy consumption of an implementation of AES with different side channel attack (SCA) countermeasures and an implementation of lightweight ciphers PRESENT, KLEIN and ZORRO with and without Boolean first order masking. In this way, we assess the additional energy consumption of using different SCA countermeasures and using lightweight block ciphers on 32 bit embedded devices. In addition to this, we provide a methodology for developing an ISA based energy model for cryptographic software with an accuracy of +/-5%. In addition to providing our methodology for developing this model, we also show that using variations of instructions that reduce the size of code can reduce the energy consumption by as much as 30% +/- 40% and that memory instructions reduce the predictability of our energy model.