Reducing Air Handler Electricity Use: More Than Just a Better Motor
A version of this article appears in the November/December 2003 issue of Home Energy Magazine.
November 01, 2003
These days, manufacturers are able to produce relatively efficient appliances for people’s homes. It is not uncommon to see A/C units with SEER 14, or furnaces with annual fuel utilization efficiency (AFUE) greater than 90%. Unfortunately, these numbers tell only part of the story.Air handlers in these systems are horribly inefficient, typically operating with efficiencies of 10%–15%. Several studies have looked at electric motor improvements (see “The Electric Side of Gas Furnaces,” p. 24).That being said, it’s time to look at the aerodynamic improvements of the fans in combination with motor improvements.The typical furnace fan suffers from the following problems: • Clearances between fan blades and scroll housing are too large—a result of large tolerances in production (see photo on p. 9).Air just sloshes around the blade tips rather than moving into the ducts. • The blades are generally stamped out of sheet steel and are not designed for optimal aerodynamic performance (see “Fanning a Revolution,”HE July/Aug ’03, p. 18). • Forward-curved blades are ...
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