Are Heat Recovery Wheels Safe During the COVID-19 Crisis?In HVAC systems, the fan unit is the most energy-consuming feature. By upgrading the fan or Air Handling Unit (AHU) with EC motor technology, commercial property owners can optimise the energy usage of their building and save on costs.  A fan array system with multiple EC motors provides the best use cases for commercial AHUs.

The HVAC industry has seen a considerable shift toward using EC motor technologies in all types of building applications. The reasoning comes down to simple maths: EC motors use on average 70% less energy than conventional HVAC fan motors.


An electronically commutated motor (ECM)—also known as an EC plug fan—can generate energy savings up to thousands of euros over its lifetime according to the European Commission. When placed in a fan array system, ECMs combine to form an even greater AHU, offering the best option for efficiency, control, reliability, and noise reduction

Comparing EC fans to other HVAC fan motors

All electric motor types operate by two magnetic fields pushing against each other. The rotor creates one magnetic field, while the stator creates another. EC Fan motors often operate anywhere from 60-90% efficiency, compared to AC or DC types which often can’t break 50% efficiency. Swiss Rotors HVAC fan motors can reach peak efficiencies up to 93%. The critical difference between the three major motor types is how these fields are maintained:

  • An EC fan is essentially a digital fan. EC motors developed by Swiss Rotors use permanent magnets to create the rotor field, and a series of coils controlled by an electronic “commutator” to create the stator field. This electronic control is what gives EC motors their benefits. It’s efficient, quiet, degrades slower, runs cooler, and can receive or send signals to a computer.
  • DC motors or brushed motors, use permanent magnets to create the stator field. A series of coils powered by DC currents uses physical (“brushes”) to create the rotor field. EC motors are digital, so they mitigate any physical wear and tear or noisy vibrations caused by brushed motors.
  • AC motors or induction units use coils powered and controlled by the AC input voltage to produce the stator field which electromagnetically creates (or “induces”) the rotor field.

An AC fan has an alternating current and is very expensive to control without making it vibrate noisily or buzz. 

Greater control and reliability

The electronics in an EC HVAC fan motor offers greater control and monitoring features. Every EC motor has sophisticated electronics built-in for communication and responsiveness. An EC motor can respond to external signals to adjust speed, and also send performance signals to a central control system, triggering warnings before inefficiencies or downtimes occur. Since they are digitally controlled without physical contact, EC motors also have a longer lifespan than DC motors. Because they have electronics controlling the stator, and do not need to waste power inducing the rotor field, they give better performance and controllability and run cooler than AC induction motors.

How EC fans create cost savings

While there are many benefits to using EC motors, very high efficiency remains the key advantage toward the total cost of ownership. ECMs can maintain part speed with lower power consumption, which translates into lower operation costs, far fewer maintenance repairs, and shorter payback periods from the initial investment. Greater energy efficiency also means that the ECMs run “cooler”, significantly reducing heat exchange. Less heat waste means better operation at the compressor level, which leads to even more energy savings. In commercial settings, energy consumption is often more than halved when running the exact same HVAC system, but switching the AHU from AC/DC to EC.

The EC fan array setup

The Swiss Rotor Fan Array offers a turnkey solution for commercial EC-powered air handling. With smaller EC motors, the entire AHU can fit into the most challenging dimensions, solving space constraints and reducing footprint. Each component in the fan array design can be hand-carried and assembled in a Lego-like method. EC motors in the Swiss Rotors Fan Array operate with wider ranges compared to belt-driven or AC/DC motors. Customers only need to choose from a simplified inventory to ease decision-making for their AHU product choices.

Final thoughts on HVAC fan motors

HVAC service professionals can be an asset in helping you choose the best fan technology for a commercial building, whether it’s a retrofit or new construction. Nowadays, EC Motors in a fan array setup are going to give you the best measured ROI when compared to other HVAC fan motors. It’s important to also shop energy-efficient options from trusted manufacturers. That’s why Swiss Rotors HVAC fans are backed by UL and AMCA certification specs. 

Get in touch with us if you’d like to learn more.