Home > Energy savings with EC fans: what can you realistically expect?

Energy savings with EC fans: what can you realistically expect?

‘Up to 50% energy savings’, you read it regularly in EC fan specifications. But what does that actually mean, and when does it apply? In this article we give an honest and substantiated picture of the energy savings you can expect.

The quadratic law: why part load delivers so much

Fans follow the fan laws (also known as the affinity or cube laws). The most relevant for energy savings:

Energy consumption drops with the square of the speed reduction
If a fan runs at 80% of its maximum speed, it consumes only 64% of maximum power
At 70% speed: 49% of power. At 60%: only 36%

In practice, a fan in an air handling, cooling or process ventilation system often runs at 60–80% of its maximum capacity. That’s precisely the range where EC technology delivers the most value.

What are realistic savings figures?

General comparison EC vs. AC (at typical part-load operating profiles):

Air handling system: 30–45% savings annually
Cooling system/condenser: 35–50% savings
Data centre cooling: 25–40% savings
Process ventilation (variable demand): 20–40% savings

Note: these are indicative figures. Actual savings depend on load profile, operating hours and the baseline (which AC system are you replacing?).

Payback period

The additional investment in EC compared to an equivalent AC fan (including external VFD) varies, but is typically limited. With realistic energy prices and an average usage profile, the payback period is usually 2 to 4 years. After that, the savings are pure gain, over a service life of 15 to 20 years.

ErP and legislation as an additional driver

The European ErP Regulation (Ecodesign) sets increasingly strict requirements on fan energy consumption. Many applications now require at least an IE3 or IE4 efficiency class. EC motors consistently score higher and therefore more easily meet these requirements. Choosing EC is not only smart from a cost perspective, but also from a compliance perspective.

Want to know what the savings are for your specific installation? Contact our specialists. We’ll work through the numbers together.