A furnace heat exchanger keeps dangerous gases out of the air circulating in the building. It's a must-have on any furnace that burns gas or oil.

A furnace heat exchanger is an essential component of a furnace. ... Natural gas is most common however, liquid propane, fuel oil and electricity are also types of readily available fuel sources.

The flames heat up a metal heat exchanger, which in turns heats incoming cold air received from your home's ductwork. ... Oil furnaces work much the same way as a natural gas furnace.

A large fan blows air across the heat exchanger, creating heated air that then disperses throughout the home to heat the individual rooms. Heat Pump vs. Furnace: Key Differences ...