Spoiler alert: Not necessarily. Even when airflow is stable, advanced variable speed drive (VSD) compressors often outperform fixed-speed models in energy efficiency – thanks to their ability to eliminate start/stop energy losses and run more efficiently at every load point.
Fact: Stable airflow does not mean constant efficiency
Only a small percentage – around 8% – of compressed air systems operate with truly stable airflow. Even then, factors like receiver tank cycling and slight demand variations can lead to energy losses in fixed-speed compressors.
Advanced VSD's like those from Atlas Copco are more efficient even under stable demand. They eliminate traditional unload and blow-off cycles, which are present in both fixed-speed compressors and many non-integrated VSD models.
Fact: Load/unload cycles waste energy – even with stable demand
Fixed-speed compressors operate at full speed regardless of demand. When air from the receiver is used, the compressor cycles on to refill it, then unloads when the tank is full again. Each cycle involves energy losses through venting (blow-off) and idle running.
Atlas Copco VSD’s avoid this waste entirely. Their design closes the inlet valve and maintains system pressure without unloading – eliminating blow-off and unnecessary cycling energy costs. This holds true even in applications with relatively constant demand.
Fact: Atlas Copco VSDs outperform fixed-speed units even at constant load
While VSD’s shine in variable demand environments, they are still more efficient in steady-state conditions. The reason is simple: they are designed with next-generation components – including high-efficiency, optimized cooling systems, and advanced control algorithms.
The outcome is a marked reduction in energy consumption whenever air demand remains steady, and in some applications, savings can reach as high as 60%. That efficiency translates into lower operating costs, reduced environmental impact, and more control over long-term system performance.
Fact check summary
Claim: Fixed-speed compressors are better for stable air demand.
Verdict: False. Even with consistent usage, modern VSD compressors deliver greater energy efficiency by eliminating start/stop losses and running more intelligently across all load conditions.
