Choose an operating system that is appropriate for the type of device's features and functionality

The operating system can greatly impact how power efficient an IoT device is.

Try to choose an operating system that is appropriate for the type of device's features and functionality.  For example, choosing Android or Linux for a simple temperature sensor may be more convenient for the developer, but is not sustainable practice due to its impact on the device's resource dimensions and consequent carbon footprint.

Consider features in the operating system that support low power modes, power management, and operational efficiency.  Operating systems must support low power modes that allow the system to conserve power when idle or when certain subsystems are not in use. For example, an embedded system might use a sleep mode to conserve power when the user is not interacting with the system, or it might shut down peripherals or subsystems that are not currently in use. The operating system should expose the hardware's low power modes such that applications can take advantage of these modes.

Some operating systems support tick-less operation, where the operating system avoids unnecessary timer interrupts, further reducing power consumption. For example, FreeRTOS stops the periodic tick interrupt during periods when there are no application tasks that are able to execute. Stopping the tick interrupt allows the microcontroller to remain in a deep power saving mode until an event occurs or the kernel is ready to execute a task.

Dynamic voltage and frequency scaling (DVFS) operations adjust the CPU performance and frequency based on the application workload's demands. Operating systems that support DVFS can decrease the CPU's voltage in real time during decreased workloads, reducing power consumption.