The international airports in Pennsylvania are Lehigh International Airport at Allentown, Erie International Airport at Erie, Harrisburg International Airport at Harrisburg, Philadelphia International Airport at Philadelphia,
Electric Plenum Heaters. A plenum heater is an electric resistance heating device that is installed in the plenum, which is the spot in the ductwork system where ducting and furnace join. Air is heated as it flows across electric elements and then is distributed through the existing ductwork.
What does Plenum rated cable mean? Plenum rated cable is required for jobs where cable is run in return air space. In most buildings this area is above drop ceilings or under raised floors. The materials required to pass plenum standards are much more expensive than non-plenum rated designs.