When it comes to fans and motors more of a good thing is not always a good thing. A recent U.S. Environmental Protection Agency (“EPA”) study stated that almost 60% of the fans within buildings today are oversized. The study went on to say that almost 10% of the fans were oversized by at least 60%. Although the magnitude of the issue may be surprising, the problem is well known to anyone involved with the design and selection of fan systems. The conservative approach, often taken when designing and purchasing a fan and motor, results in a product that exceeds the system requirements and consumes more energy than necessary.
Oversizing fan/motor systems can end up creating a host of other issues, including higher installed and operating costs, increased maintenance, and possibly a higher level of vibration and noise. It is very common for the application of safety margins to be compounded through the specification and purchase process with the accepted remedy being the addition of a VFD, “to ramp down the speed.”