- ESP-IDF provides the lowest and most consistent power consumption (~24.77 mA) across all tested workloads due to native FreeRTOS, peripheral clock gating, and a more advanced compiler (GCC 14.2.0 with -O3).
- Arduino shows an anomalous 35% higher baseline current in the Empty scenario (33.57 mA) compared to its active workloads, suggesting background services remain active unless explicitly managed by user code.
- Zephyr RTOS has a consistent overhead of +2 to +3 mA over ESP-IDF, representing a 10-12% battery life reduction for simple tasks, attributed to its hardware abstraction layer and modular RTOS scheduler.
- A software bug (stack overflow) during Arduino's Floating-point test caused current spikes and system crashes, demonstrating that code stability directly impacts energy efficiency.
- The study followed an 'Out-of-the-Box' policy with no power-saving modes enabled, meaning results reflect default awake/idle behavior and not the chip's lowest possible power states.