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.
Definition of Plenum in Construction. A plenum is a space designated for air flow or can describe a space devoted to mechanical, electrical or sprinkler lines. The term plenum, could be a large section of ductwork, or the upper space above a ceiling. Any large space designated for any type of air flow or routing of systems, can be called a plenum. The space providing air is called a supply plenum and the space providing air return is referred to as a return plenum.