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 is a heat exchanger? Inside each furnace there is a heat exchanger. The heat exchanger is a thin-walled metal device that is designed to burn fuel inside it. Air that circulates throughout your home is blown over the outside of the heat exchanger in order to be heated.